MAP: Convert from DPO to input feature.
[vpp.git] / test / test_nat.py
index 4470a05..c64359a 100644 (file)
 import socket
 import unittest
 import struct
-import StringIO
 import random
 
 from framework import VppTestCase, VppTestRunner, running_extended_tests
-from vpp_ip_route import VppIpRoute, VppRoutePath, DpoProto
 from scapy.layers.inet import IP, TCP, UDP, ICMP
 from scapy.layers.inet import IPerror, TCPerror, UDPerror, ICMPerror
-from scapy.layers.inet6 import IPv6, ICMPv6EchoRequest, ICMPv6EchoReply
+from scapy.layers.inet6 import IPv6, ICMPv6EchoRequest, ICMPv6EchoReply, \
+    ICMPv6ND_NS, ICMPv6ND_NA, ICMPv6NDOptDstLLAddr, fragment6
 from scapy.layers.inet6 import ICMPv6DestUnreach, IPerror6, IPv6ExtHdrFragment
 from scapy.layers.l2 import Ether, ARP, GRE
 from scapy.data import IP_PROTOS
 from scapy.packet import bind_layers, Raw
-from scapy.all import fragment6
 from util import ppp
 from ipfix import IPFIX, Set, Template, Data, IPFIXDecoder
 from time import sleep
 from util import ip4_range
-from util import mactobinary
+from vpp_papi import mac_pton
+from syslog_rfc5424_parser import SyslogMessage, ParseError
+from syslog_rfc5424_parser.constants import SyslogFacility, SyslogSeverity
+from vpp_papi_provider import SYSLOG_SEVERITY
+from io import BytesIO
 
 
 class MethodHolder(VppTestCase):
     """ NAT create capture and verify method holder """
 
-    @classmethod
-    def setUpClass(cls):
-        super(MethodHolder, cls).setUpClass()
+    def clear_nat44(self):
+        """
+        Clear NAT44 configuration.
+        """
+        if hasattr(self, 'pg7') and hasattr(self, 'pg8'):
+            # I found no elegant way to do this
+            self.vapi.ip_add_del_route(
+                dst_address=self.pg7.remote_ip4n,
+                dst_address_length=32,
+                next_hop_address=self.pg7.remote_ip4n,
+                next_hop_sw_if_index=self.pg7.sw_if_index,
+                is_add=0)
+            self.vapi.ip_add_del_route(
+                dst_address=self.pg8.remote_ip4n,
+                dst_address_length=32,
+                next_hop_address=self.pg8.remote_ip4n,
+                next_hop_sw_if_index=self.pg8.sw_if_index,
+                is_add=0)
 
-    def tearDown(self):
-        super(MethodHolder, self).tearDown()
+            for intf in [self.pg7, self.pg8]:
+                neighbors = self.vapi.ip_neighbor_dump(intf.sw_if_index)
+                for n in neighbors:
+                    self.vapi.ip_neighbor_add_del(intf.sw_if_index,
+                                                  n.mac_address,
+                                                  n.ip_address,
+                                                  is_add=0)
 
-    def check_ip_checksum(self, pkt):
-        """
-        Check IP checksum of the packet
+            if self.pg7.has_ip4_config:
+                self.pg7.unconfig_ip4()
 
-        :param pkt: Packet to check IP checksum
-        """
-        new = pkt.__class__(str(pkt))
-        del new['IP'].chksum
-        new = new.__class__(str(new))
-        self.assertEqual(new['IP'].chksum, pkt['IP'].chksum)
+        self.vapi.nat44_forwarding_enable_disable(0)
 
-    def check_tcp_checksum(self, pkt):
-        """
-        Check TCP checksum in IP packet
+        interfaces = self.vapi.nat44_interface_addr_dump()
+        for intf in interfaces:
+            self.vapi.nat44_add_interface_addr(intf.sw_if_index,
+                                               twice_nat=intf.twice_nat,
+                                               is_add=0)
 
-        :param pkt: Packet to check TCP checksum
-        """
-        new = pkt.__class__(str(pkt))
-        del new['TCP'].chksum
-        new = new.__class__(str(new))
-        self.assertEqual(new['TCP'].chksum, pkt['TCP'].chksum)
+        self.vapi.nat_ipfix(enable=0, src_port=self.ipfix_src_port,
+                            domain_id=self.ipfix_domain_id)
+        self.ipfix_src_port = 4739
+        self.ipfix_domain_id = 1
 
-    def check_udp_checksum(self, pkt):
-        """
-        Check UDP checksum in IP packet
+        self.vapi.syslog_set_filter(SYSLOG_SEVERITY.EMERG)
 
-        :param pkt: Packet to check UDP checksum
-        """
-        new = pkt.__class__(str(pkt))
-        del new['UDP'].chksum
-        new = new.__class__(str(new))
-        self.assertEqual(new['UDP'].chksum, pkt['UDP'].chksum)
+        interfaces = self.vapi.nat44_interface_dump()
+        for intf in interfaces:
+            if intf.is_inside > 1:
+                self.vapi.nat44_interface_add_del_feature(intf.sw_if_index,
+                                                          0,
+                                                          is_add=0)
+            self.vapi.nat44_interface_add_del_feature(intf.sw_if_index,
+                                                      intf.is_inside,
+                                                      is_add=0)
 
-    def check_icmp_errror_embedded(self, pkt):
-        """
-        Check ICMP error embeded packet checksum
+        interfaces = self.vapi.nat44_interface_output_feature_dump()
+        for intf in interfaces:
+            self.vapi.nat44_interface_add_del_output_feature(intf.sw_if_index,
+                                                             intf.is_inside,
+                                                             is_add=0)
 
-        :param pkt: Packet to check ICMP error embeded packet checksum
-        """
-        if pkt.haslayer(IPerror):
-            new = pkt.__class__(str(pkt))
-            del new['IPerror'].chksum
-            new = new.__class__(str(new))
-            self.assertEqual(new['IPerror'].chksum, pkt['IPerror'].chksum)
-
-        if pkt.haslayer(TCPerror):
-            new = pkt.__class__(str(pkt))
-            del new['TCPerror'].chksum
-            new = new.__class__(str(new))
-            self.assertEqual(new['TCPerror'].chksum, pkt['TCPerror'].chksum)
-
-        if pkt.haslayer(UDPerror):
-            if pkt['UDPerror'].chksum != 0:
-                new = pkt.__class__(str(pkt))
-                del new['UDPerror'].chksum
-                new = new.__class__(str(new))
-                self.assertEqual(new['UDPerror'].chksum,
-                                 pkt['UDPerror'].chksum)
-
-        if pkt.haslayer(ICMPerror):
-            del new['ICMPerror'].chksum
-            new = new.__class__(str(new))
-            self.assertEqual(new['ICMPerror'].chksum, pkt['ICMPerror'].chksum)
-
-    def check_icmp_checksum(self, pkt):
+        static_mappings = self.vapi.nat44_static_mapping_dump()
+        for sm in static_mappings:
+            self.vapi.nat44_add_del_static_mapping(
+                sm.local_ip_address,
+                sm.external_ip_address,
+                local_port=sm.local_port,
+                external_port=sm.external_port,
+                addr_only=sm.addr_only,
+                vrf_id=sm.vrf_id,
+                protocol=sm.protocol,
+                twice_nat=sm.twice_nat,
+                self_twice_nat=sm.self_twice_nat,
+                out2in_only=sm.out2in_only,
+                tag=sm.tag,
+                external_sw_if_index=sm.external_sw_if_index,
+                is_add=0)
+
+        lb_static_mappings = self.vapi.nat44_lb_static_mapping_dump()
+        for lb_sm in lb_static_mappings:
+            self.vapi.nat44_add_del_lb_static_mapping(
+                lb_sm.external_addr,
+                lb_sm.external_port,
+                lb_sm.protocol,
+                twice_nat=lb_sm.twice_nat,
+                self_twice_nat=lb_sm.self_twice_nat,
+                out2in_only=lb_sm.out2in_only,
+                tag=lb_sm.tag,
+                is_add=0,
+                local_num=0,
+                locals=[])
+
+        identity_mappings = self.vapi.nat44_identity_mapping_dump()
+        for id_m in identity_mappings:
+            self.vapi.nat44_add_del_identity_mapping(
+                addr_only=id_m.addr_only,
+                ip=id_m.ip_address,
+                port=id_m.port,
+                sw_if_index=id_m.sw_if_index,
+                vrf_id=id_m.vrf_id,
+                protocol=id_m.protocol,
+                is_add=0)
+
+        adresses = self.vapi.nat44_address_dump()
+        for addr in adresses:
+            self.vapi.nat44_add_del_address_range(addr.ip_address,
+                                                  addr.ip_address,
+                                                  twice_nat=addr.twice_nat,
+                                                  is_add=0)
+
+        self.vapi.nat_set_reass()
+        self.vapi.nat_set_reass(is_ip6=1)
+        self.verify_no_nat44_user()
+        self.vapi.nat_set_timeouts()
+        self.vapi.nat_set_addr_and_port_alloc_alg()
+        self.vapi.nat_set_mss_clamping()
+
+    def nat44_add_static_mapping(self, local_ip, external_ip='0.0.0.0',
+                                 local_port=0, external_port=0, vrf_id=0,
+                                 is_add=1, external_sw_if_index=0xFFFFFFFF,
+                                 proto=0, twice_nat=0, self_twice_nat=0,
+                                 out2in_only=0, tag=""):
         """
-        Check ICMP checksum in IPv4 packet
+        Add/delete NAT44 static mapping
 
-        :param pkt: Packet to check ICMP checksum
+        :param local_ip: Local IP address
+        :param external_ip: External IP address
+        :param local_port: Local port number (Optional)
+        :param external_port: External port number (Optional)
+        :param vrf_id: VRF ID (Default 0)
+        :param is_add: 1 if add, 0 if delete (Default add)
+        :param external_sw_if_index: External interface instead of IP address
+        :param proto: IP protocol (Mandatory if port specified)
+        :param twice_nat: 1 if translate external host address and port
+        :param self_twice_nat: 1 if translate external host address and port
+                               whenever external host address equals
+                               local address of internal host
+        :param out2in_only: if 1 rule is matching only out2in direction
+        :param tag: Opaque string tag
         """
-        new = pkt.__class__(str(pkt))
-        del new['ICMP'].chksum
-        new = new.__class__(str(new))
-        self.assertEqual(new['ICMP'].chksum, pkt['ICMP'].chksum)
-        if pkt.haslayer(IPerror):
-            self.check_icmp_errror_embedded(pkt)
-
-    def check_icmpv6_checksum(self, pkt):
+        addr_only = 1
+        if local_port and external_port:
+            addr_only = 0
+        l_ip = socket.inet_pton(socket.AF_INET, local_ip)
+        e_ip = socket.inet_pton(socket.AF_INET, external_ip)
+        self.vapi.nat44_add_del_static_mapping(
+            l_ip,
+            e_ip,
+            external_sw_if_index,
+            local_port,
+            external_port,
+            addr_only,
+            vrf_id,
+            proto,
+            twice_nat,
+            self_twice_nat,
+            out2in_only,
+            tag,
+            is_add)
+
+    def nat44_add_address(self, ip, is_add=1, vrf_id=0xFFFFFFFF, twice_nat=0):
         """
-        Check ICMPv6 checksum in IPv4 packet
+        Add/delete NAT44 address
 
-        :param pkt: Packet to check ICMPv6 checksum
+        :param ip: IP address
+        :param is_add: 1 if add, 0 if delete (Default add)
+        :param twice_nat: twice NAT address for extenal hosts
         """
-        new = pkt.__class__(str(pkt))
-        if pkt.haslayer(ICMPv6DestUnreach):
-            del new['ICMPv6DestUnreach'].cksum
-            new = new.__class__(str(new))
-            self.assertEqual(new['ICMPv6DestUnreach'].cksum,
-                             pkt['ICMPv6DestUnreach'].cksum)
-            self.check_icmp_errror_embedded(pkt)
-        if pkt.haslayer(ICMPv6EchoRequest):
-            del new['ICMPv6EchoRequest'].cksum
-            new = new.__class__(str(new))
-            self.assertEqual(new['ICMPv6EchoRequest'].cksum,
-                             pkt['ICMPv6EchoRequest'].cksum)
-        if pkt.haslayer(ICMPv6EchoReply):
-            del new['ICMPv6EchoReply'].cksum
-            new = new.__class__(str(new))
-            self.assertEqual(new['ICMPv6EchoReply'].cksum,
-                             pkt['ICMPv6EchoReply'].cksum)
+        nat_addr = socket.inet_pton(socket.AF_INET, ip)
+        self.vapi.nat44_add_del_address_range(nat_addr, nat_addr, is_add,
+                                              vrf_id=vrf_id,
+                                              twice_nat=twice_nat)
 
     def create_stream_in(self, in_if, out_if, dst_ip=None, ttl=64):
         """
@@ -360,14 +427,13 @@ class MethodHolder(VppTestCase):
         return pkts
 
     def verify_capture_out(self, capture, nat_ip=None, same_port=False,
-                           packet_num=3, dst_ip=None, is_ip6=False):
+                           dst_ip=None, is_ip6=False):
         """
         Verify captured packets on outside network
 
         :param capture: Captured packets
         :param nat_ip: Translated IP address (Default use global NAT address)
         :param same_port: Sorce port number is not translated (Default False)
-        :param packet_num: Expected number of packets (Default 3)
         :param dst_ip: Destination IP address (Default do not verify)
         :param is_ip6: If L3 protocol is IPv6 (Default False)
         """
@@ -379,11 +445,10 @@ class MethodHolder(VppTestCase):
             ICMP46 = ICMP
         if nat_ip is None:
             nat_ip = self.nat_addr
-        self.assertEqual(packet_num, len(capture))
         for packet in capture:
             try:
                 if not is_ip6:
-                    self.check_ip_checksum(packet)
+                    self.assert_packet_checksums_valid(packet)
                 self.assertEqual(packet[IP46].src, nat_ip)
                 if dst_ip is not None:
                     self.assertEqual(packet[IP46].dst, dst_ip)
@@ -394,7 +459,7 @@ class MethodHolder(VppTestCase):
                         self.assertNotEqual(
                             packet[TCP].sport, self.tcp_port_in)
                     self.tcp_port_out = packet[TCP].sport
-                    self.check_tcp_checksum(packet)
+                    self.assert_packet_checksums_valid(packet)
                 elif packet.haslayer(UDP):
                     if same_port:
                         self.assertEqual(packet[UDP].sport, self.udp_port_in)
@@ -408,79 +473,67 @@ class MethodHolder(VppTestCase):
                     else:
                         self.assertNotEqual(packet[ICMP46].id, self.icmp_id_in)
                     self.icmp_id_out = packet[ICMP46].id
-                    if is_ip6:
-                        self.check_icmpv6_checksum(packet)
-                    else:
-                        self.check_icmp_checksum(packet)
+                    self.assert_packet_checksums_valid(packet)
             except:
                 self.logger.error(ppp("Unexpected or invalid packet "
                                       "(outside network):", packet))
                 raise
 
     def verify_capture_out_ip6(self, capture, nat_ip, same_port=False,
-                               packet_num=3, dst_ip=None):
+                               dst_ip=None):
         """
         Verify captured packets on outside network
 
         :param capture: Captured packets
         :param nat_ip: Translated IP address
         :param same_port: Sorce port number is not translated (Default False)
-        :param packet_num: Expected number of packets (Default 3)
         :param dst_ip: Destination IP address (Default do not verify)
         """
-        return self.verify_capture_out(capture, nat_ip, same_port, packet_num,
-                                       dst_ip, True)
+        return self.verify_capture_out(capture, nat_ip, same_port, dst_ip,
+                                       True)
 
-    def verify_capture_in(self, capture, in_if, packet_num=3):
+    def verify_capture_in(self, capture, in_if):
         """
         Verify captured packets on inside network
 
         :param capture: Captured packets
         :param in_if: Inside interface
-        :param packet_num: Expected number of packets (Default 3)
         """
-        self.assertEqual(packet_num, len(capture))
         for packet in capture:
             try:
-                self.check_ip_checksum(packet)
+                self.assert_packet_checksums_valid(packet)
                 self.assertEqual(packet[IP].dst, in_if.remote_ip4)
                 if packet.haslayer(TCP):
                     self.assertEqual(packet[TCP].dport, self.tcp_port_in)
-                    self.check_tcp_checksum(packet)
                 elif packet.haslayer(UDP):
                     self.assertEqual(packet[UDP].dport, self.udp_port_in)
                 else:
                     self.assertEqual(packet[ICMP].id, self.icmp_id_in)
-                    self.check_icmp_checksum(packet)
             except:
                 self.logger.error(ppp("Unexpected or invalid packet "
                                       "(inside network):", packet))
                 raise
 
-    def verify_capture_in_ip6(self, capture, src_ip, dst_ip, packet_num=3):
+    def verify_capture_in_ip6(self, capture, src_ip, dst_ip):
         """
         Verify captured IPv6 packets on inside network
 
         :param capture: Captured packets
         :param src_ip: Source IP
         :param dst_ip: Destination IP address
-        :param packet_num: Expected number of packets (Default 3)
         """
-        self.assertEqual(packet_num, len(capture))
         for packet in capture:
             try:
                 self.assertEqual(packet[IPv6].src, src_ip)
                 self.assertEqual(packet[IPv6].dst, dst_ip)
+                self.assert_packet_checksums_valid(packet)
                 if packet.haslayer(TCP):
                     self.assertEqual(packet[TCP].dport, self.tcp_port_in)
-                    self.check_tcp_checksum(packet)
                 elif packet.haslayer(UDP):
                     self.assertEqual(packet[UDP].dport, self.udp_port_in)
-                    self.check_udp_checksum(packet)
                 else:
                     self.assertEqual(packet[ICMPv6EchoReply].id,
                                      self.icmp_id_in)
-                    self.check_icmpv6_checksum(packet)
             except:
                 self.logger.error(ppp("Unexpected or invalid packet "
                                       "(inside network):", packet))
@@ -510,24 +563,22 @@ class MethodHolder(VppTestCase):
                 raise
 
     def verify_capture_out_with_icmp_errors(self, capture, src_ip=None,
-                                            packet_num=3, icmp_type=11):
+                                            icmp_type=11):
         """
         Verify captured packets with ICMP errors on outside network
 
         :param capture: Captured packets
         :param src_ip: Translated IP address or IP address of VPP
                        (Default use global NAT address)
-        :param packet_num: Expected number of packets (Default 3)
         :param icmp_type: Type of error ICMP packet
                           we are expecting (Default 11)
         """
         if src_ip is None:
             src_ip = self.nat_addr
-        self.assertEqual(packet_num, len(capture))
         for packet in capture:
             try:
                 self.assertEqual(packet[IP].src, src_ip)
-                self.assertTrue(packet.haslayer(ICMP))
+                self.assertEqual(packet.haslayer(ICMP), 1)
                 icmp = packet[ICMP]
                 self.assertEqual(icmp.type, icmp_type)
                 self.assertTrue(icmp.haslayer(IPerror))
@@ -545,22 +596,19 @@ class MethodHolder(VppTestCase):
                                       "(outside network):", packet))
                 raise
 
-    def verify_capture_in_with_icmp_errors(self, capture, in_if, packet_num=3,
-                                           icmp_type=11):
+    def verify_capture_in_with_icmp_errors(self, capture, in_if, icmp_type=11):
         """
         Verify captured packets with ICMP errors on inside network
 
         :param capture: Captured packets
         :param in_if: Inside interface
-        :param packet_num: Expected number of packets (Default 3)
         :param icmp_type: Type of error ICMP packet
                           we are expecting (Default 11)
         """
-        self.assertEqual(packet_num, len(capture))
         for packet in capture:
             try:
                 self.assertEqual(packet[IP].dst, in_if.remote_ip4)
-                self.assertTrue(packet.haslayer(ICMP))
+                self.assertEqual(packet.haslayer(ICMP), 1)
                 icmp = packet[ICMP]
                 self.assertEqual(icmp.type, icmp_type)
                 self.assertTrue(icmp.haslayer(IPerror))
@@ -578,38 +626,64 @@ class MethodHolder(VppTestCase):
                                       "(inside network):", packet))
                 raise
 
-    def create_stream_frag(self, src_if, dst, sport, dport, data):
+    def create_stream_frag(self, src_if, dst, sport, dport, data,
+                           proto=IP_PROTOS.tcp, echo_reply=False):
         """
         Create fragmented packet stream
 
         :param src_if: Source interface
         :param dst: Destination IPv4 address
-        :param sport: Source TCP port
-        :param dport: Destination TCP port
+        :param sport: Source port
+        :param dport: Destination port
         :param data: Payload data
+        :param proto: protocol (TCP, UDP, ICMP)
+        :param echo_reply: use echo_reply if protocol is ICMP
         :returns: Fragmets
         """
+        if proto == IP_PROTOS.tcp:
+            p = (IP(src=src_if.remote_ip4, dst=dst) /
+                 TCP(sport=sport, dport=dport) /
+                 Raw(data))
+            p = p.__class__(str(p))
+            chksum = p['TCP'].chksum
+            proto_header = TCP(sport=sport, dport=dport, chksum=chksum)
+        elif proto == IP_PROTOS.udp:
+            proto_header = UDP(sport=sport, dport=dport)
+        elif proto == IP_PROTOS.icmp:
+            if not echo_reply:
+                proto_header = ICMP(id=sport, type='echo-request')
+            else:
+                proto_header = ICMP(id=sport, type='echo-reply')
+        else:
+            raise Exception("Unsupported protocol")
         id = random.randint(0, 65535)
-        p = (IP(src=src_if.remote_ip4, dst=dst) /
-             TCP(sport=sport, dport=dport) /
-             Raw(data))
-        p = p.__class__(str(p))
-        chksum = p['TCP'].chksum
         pkts = []
+        if proto == IP_PROTOS.tcp:
+            raw = Raw(data[0:4])
+        else:
+            raw = Raw(data[0:16])
         p = (Ether(src=src_if.remote_mac, dst=src_if.local_mac) /
              IP(src=src_if.remote_ip4, dst=dst, flags="MF", frag=0, id=id) /
-             TCP(sport=sport, dport=dport, chksum=chksum) /
-             Raw(data[0:4]))
+             proto_header /
+             raw)
         pkts.append(p)
+        if proto == IP_PROTOS.tcp:
+            raw = Raw(data[4:20])
+        else:
+            raw = Raw(data[16:32])
         p = (Ether(src=src_if.remote_mac, dst=src_if.local_mac) /
              IP(src=src_if.remote_ip4, dst=dst, flags="MF", frag=3, id=id,
-                proto=IP_PROTOS.tcp) /
-             Raw(data[4:20]))
+                proto=proto) /
+             raw)
         pkts.append(p)
+        if proto == IP_PROTOS.tcp:
+            raw = Raw(data[20:])
+        else:
+            raw = Raw(data[32:])
         p = (Ether(src=src_if.remote_mac, dst=src_if.local_mac) /
-             IP(src=src_if.remote_ip4, dst=dst, frag=5, proto=IP_PROTOS.tcp,
+             IP(src=src_if.remote_ip4, dst=dst, frag=5, proto=proto,
                 id=id) /
-             Raw(data[20:]))
+             raw)
         pkts.append(p)
         return pkts
 
@@ -651,21 +725,23 @@ class MethodHolder(VppTestCase):
 
         :returns: Reassembled IPv4 packet
         """
-        buffer = StringIO.StringIO()
+        buffer = BytesIO()
         for p in frags:
             self.assertEqual(p[IP].src, src)
             self.assertEqual(p[IP].dst, dst)
-            self.check_ip_checksum(p)
+            self.assert_ip_checksum_valid(p)
             buffer.seek(p[IP].frag * 8)
-            buffer.write(p[IP].payload)
-        ip = frags[0].getlayer(IP)
+            buffer.write(bytes(p[IP].payload))
         ip = IP(src=frags[0][IP].src, dst=frags[0][IP].dst,
                 proto=frags[0][IP].proto)
         if ip.proto == IP_PROTOS.tcp:
             p = (ip / TCP(buffer.getvalue()))
-            self.check_tcp_checksum(p)
+            self.assert_tcp_checksum_valid(p)
         elif ip.proto == IP_PROTOS.udp:
-            p = (ip / UDP(buffer.getvalue()))
+            p = (ip / UDP(buffer.getvalue()[:8]) /
+                 Raw(buffer.getvalue()[8:]))
+        elif ip.proto == IP_PROTOS.icmp:
+            p = (ip / ICMP(buffer.getvalue()))
         return p
 
     def reass_frags_and_verify_ip6(self, frags, src, dst):
@@ -678,21 +754,65 @@ class MethodHolder(VppTestCase):
 
         :returns: Reassembled IPv6 packet
         """
-        buffer = StringIO.StringIO()
+        buffer = BytesIO()
         for p in frags:
             self.assertEqual(p[IPv6].src, src)
             self.assertEqual(p[IPv6].dst, dst)
             buffer.seek(p[IPv6ExtHdrFragment].offset * 8)
-            buffer.write(p[IPv6ExtHdrFragment].payload)
+            buffer.write(bytes(p[IPv6ExtHdrFragment].payload))
         ip = IPv6(src=frags[0][IPv6].src, dst=frags[0][IPv6].dst,
                   nh=frags[0][IPv6ExtHdrFragment].nh)
         if ip.nh == IP_PROTOS.tcp:
             p = (ip / TCP(buffer.getvalue()))
-            self.check_tcp_checksum(p)
         elif ip.nh == IP_PROTOS.udp:
             p = (ip / UDP(buffer.getvalue()))
+        self.assert_packet_checksums_valid(p)
         return p
 
+    def initiate_tcp_session(self, in_if, out_if):
+        """
+        Initiates TCP session
+
+        :param in_if: Inside interface
+        :param out_if: Outside interface
+        """
+        try:
+            # SYN packet in->out
+            p = (Ether(src=in_if.remote_mac, dst=in_if.local_mac) /
+                 IP(src=in_if.remote_ip4, dst=out_if.remote_ip4) /
+                 TCP(sport=self.tcp_port_in, dport=self.tcp_external_port,
+                     flags="S"))
+            in_if.add_stream(p)
+            self.pg_enable_capture(self.pg_interfaces)
+            self.pg_start()
+            capture = out_if.get_capture(1)
+            p = capture[0]
+            self.tcp_port_out = p[TCP].sport
+
+            # SYN + ACK packet out->in
+            p = (Ether(src=out_if.remote_mac, dst=out_if.local_mac) /
+                 IP(src=out_if.remote_ip4, dst=self.nat_addr) /
+                 TCP(sport=self.tcp_external_port, dport=self.tcp_port_out,
+                     flags="SA"))
+            out_if.add_stream(p)
+            self.pg_enable_capture(self.pg_interfaces)
+            self.pg_start()
+            in_if.get_capture(1)
+
+            # ACK packet in->out
+            p = (Ether(src=in_if.remote_mac, dst=in_if.local_mac) /
+                 IP(src=in_if.remote_ip4, dst=out_if.remote_ip4) /
+                 TCP(sport=self.tcp_port_in, dport=self.tcp_external_port,
+                     flags="A"))
+            in_if.add_stream(p)
+            self.pg_enable_capture(self.pg_interfaces)
+            self.pg_start()
+            out_if.get_capture(1)
+
+        except:
+            self.logger.error("TCP 3 way handshake failed")
+            raise
+
     def verify_ipfix_nat44_ses(self, data):
         """
         Verify IPFIX NAT44 session create/delete event
@@ -891,59 +1011,486 @@ class MethodHolder(VppTestCase):
         # postNAPTDestinationTransportPort
         self.assertEqual(struct.pack("!H", dst_port), record[228])
 
+    def verify_no_nat44_user(self):
+        """ Verify that there is no NAT44 user """
+        users = self.vapi.nat44_user_dump()
+        self.assertEqual(len(users), 0)
+        users = self.statistics.get_counter('/nat44/total-users')
+        self.assertEqual(users[0][0], 0)
+        sessions = self.statistics.get_counter('/nat44/total-sessions')
+        self.assertEqual(sessions[0][0], 0)
 
-class TestNAT44(MethodHolder):
-    """ NAT44 Test Cases """
+    def verify_ipfix_max_entries_per_user(self, data, limit, src_addr):
+        """
+        Verify IPFIX maximum entries per user exceeded event
 
-    @classmethod
-    def setUpClass(cls):
-        super(TestNAT44, cls).setUpClass()
+        :param data: Decoded IPFIX data records
+        :param limit: Number of maximum entries per user
+        :param src_addr: IPv4 source address
+        """
+        self.assertEqual(1, len(data))
+        record = data[0]
+        # natEvent
+        self.assertEqual(ord(record[230]), 13)
+        # natQuotaExceededEvent
+        self.assertEqual(struct.pack("I", 3), record[466])
+        # maxEntriesPerUser
+        self.assertEqual(struct.pack("I", limit), record[473])
+        # sourceIPv4Address
+        self.assertEqual(src_addr, record[8])
 
+    def verify_syslog_apmap(self, data, is_add=True):
+        message = data.decode('utf-8')
         try:
-            cls.tcp_port_in = 6303
-            cls.tcp_port_out = 6303
-            cls.udp_port_in = 6304
-            cls.udp_port_out = 6304
-            cls.icmp_id_in = 6305
-            cls.icmp_id_out = 6305
-            cls.nat_addr = '10.0.0.3'
-            cls.nat_addr_n = socket.inet_pton(socket.AF_INET, cls.nat_addr)
-            cls.ipfix_src_port = 4739
-            cls.ipfix_domain_id = 1
-
-            cls.create_pg_interfaces(range(10))
-            cls.interfaces = list(cls.pg_interfaces[0:4])
+            message = SyslogMessage.parse(message)
+            self.assertEqual(message.severity, SyslogSeverity.info)
+            self.assertEqual(message.appname, 'NAT')
+            self.assertEqual(message.msgid, 'APMADD' if is_add else 'APMDEL')
+            sd_params = message.sd.get('napmap')
+            self.assertTrue(sd_params is not None)
+            self.assertEqual(sd_params.get('IATYP'), 'IPv4')
+            self.assertEqual(sd_params.get('ISADDR'), self.pg0.remote_ip4)
+            self.assertEqual(sd_params.get('ISPORT'), "%d" % self.tcp_port_in)
+            self.assertEqual(sd_params.get('XATYP'), 'IPv4')
+            self.assertEqual(sd_params.get('XSADDR'), self.nat_addr)
+            self.assertEqual(sd_params.get('XSPORT'), "%d" % self.tcp_port_out)
+            self.assertEqual(sd_params.get('PROTO'), "%d" % IP_PROTOS.tcp)
+            self.assertTrue(sd_params.get('SSUBIX') is not None)
+            self.assertEqual(sd_params.get('SVLAN'), '0')
+        except ParseError as e:
+            self.logger.error(e)
+
+    def verify_syslog_sess(self, data, is_add=True, is_ip6=False):
+        message = data.decode('utf-8')
+        try:
+            message = SyslogMessage.parse(message)
+            self.assertEqual(message.severity, SyslogSeverity.info)
+            self.assertEqual(message.appname, 'NAT')
+            self.assertEqual(message.msgid, 'SADD' if is_add else 'SDEL')
+            sd_params = message.sd.get('nsess')
+            self.assertTrue(sd_params is not None)
+            if is_ip6:
+                self.assertEqual(sd_params.get('IATYP'), 'IPv6')
+                self.assertEqual(sd_params.get('ISADDR'), self.pg0.remote_ip6)
+            else:
+                self.assertEqual(sd_params.get('IATYP'), 'IPv4')
+                self.assertEqual(sd_params.get('ISADDR'), self.pg0.remote_ip4)
+                self.assertTrue(sd_params.get('SSUBIX') is not None)
+            self.assertEqual(sd_params.get('ISPORT'), "%d" % self.tcp_port_in)
+            self.assertEqual(sd_params.get('XATYP'), 'IPv4')
+            self.assertEqual(sd_params.get('XSADDR'), self.nat_addr)
+            self.assertEqual(sd_params.get('XSPORT'), "%d" % self.tcp_port_out)
+            self.assertEqual(sd_params.get('PROTO'), "%d" % IP_PROTOS.tcp)
+            self.assertEqual(sd_params.get('SVLAN'), '0')
+            self.assertEqual(sd_params.get('XDADDR'), self.pg1.remote_ip4)
+            self.assertEqual(sd_params.get('XDPORT'),
+                             "%d" % self.tcp_external_port)
+        except ParseError as e:
+            self.logger.error(e)
+
+    def verify_mss_value(self, pkt, mss):
+        """
+        Verify TCP MSS value
 
-            for i in cls.interfaces:
-                i.admin_up()
-                i.config_ip4()
-                i.resolve_arp()
+        :param pkt:
+        :param mss:
+        """
+        if not pkt.haslayer(IP) or not pkt.haslayer(TCP):
+            raise TypeError("Not a TCP/IP packet")
+
+        for option in pkt[TCP].options:
+            if option[0] == 'MSS':
+                self.assertEqual(option[1], mss)
+                self.assert_tcp_checksum_valid(pkt)
+
+    @staticmethod
+    def proto2layer(proto):
+        if proto == IP_PROTOS.tcp:
+            return TCP
+        elif proto == IP_PROTOS.udp:
+            return UDP
+        elif proto == IP_PROTOS.icmp:
+            return ICMP
+        else:
+            raise Exception("Unsupported protocol")
 
-            cls.pg0.generate_remote_hosts(3)
-            cls.pg0.configure_ipv4_neighbors()
+    def frag_in_order(self, proto=IP_PROTOS.tcp, dont_translate=False):
+        layer = self.proto2layer(proto)
 
-            cls.overlapping_interfaces = list(list(cls.pg_interfaces[4:7]))
-            cls.vapi.ip_table_add_del(10, is_add=1)
-            cls.vapi.ip_table_add_del(20, is_add=1)
+        if proto == IP_PROTOS.tcp:
+            data = "A" * 4 + "B" * 16 + "C" * 3
+        else:
+            data = "A" * 16 + "B" * 16 + "C" * 3
+        self.port_in = random.randint(1025, 65535)
 
-            cls.pg4._local_ip4 = "172.16.255.1"
-            cls.pg4._local_ip4n = socket.inet_pton(socket.AF_INET, i.local_ip4)
-            cls.pg4._remote_hosts[0]._ip4 = "172.16.255.2"
-            cls.pg4.set_table_ip4(10)
-            cls.pg5._local_ip4 = "172.17.255.3"
-            cls.pg5._local_ip4n = socket.inet_pton(socket.AF_INET, i.local_ip4)
-            cls.pg5._remote_hosts[0]._ip4 = "172.17.255.4"
-            cls.pg5.set_table_ip4(10)
-            cls.pg6._local_ip4 = "172.16.255.1"
-            cls.pg6._local_ip4n = socket.inet_pton(socket.AF_INET, i.local_ip4)
-            cls.pg6._remote_hosts[0]._ip4 = "172.16.255.2"
-            cls.pg6.set_table_ip4(20)
-            for i in cls.overlapping_interfaces:
-                i.config_ip4()
-                i.admin_up()
-                i.resolve_arp()
+        reass = self.vapi.nat_reass_dump()
+        reass_n_start = len(reass)
 
-            cls.pg7.admin_up()
+        # in2out
+        pkts = self.create_stream_frag(self.pg0,
+                                       self.pg1.remote_ip4,
+                                       self.port_in,
+                                       20,
+                                       data,
+                                       proto)
+        self.pg0.add_stream(pkts)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        frags = self.pg1.get_capture(len(pkts))
+        if not dont_translate:
+            p = self.reass_frags_and_verify(frags,
+                                            self.nat_addr,
+                                            self.pg1.remote_ip4)
+        else:
+            p = self.reass_frags_and_verify(frags,
+                                            self.pg0.remote_ip4,
+                                            self.pg1.remote_ip4)
+        if proto != IP_PROTOS.icmp:
+            if not dont_translate:
+                self.assertEqual(p[layer].dport, 20)
+                self.assertNotEqual(p[layer].sport, self.port_in)
+            else:
+                self.assertEqual(p[layer].sport, self.port_in)
+        else:
+            if not dont_translate:
+                self.assertNotEqual(p[layer].id, self.port_in)
+            else:
+                self.assertEqual(p[layer].id, self.port_in)
+        self.assertEqual(data, p[Raw].load)
+
+        # out2in
+        if not dont_translate:
+            dst_addr = self.nat_addr
+        else:
+            dst_addr = self.pg0.remote_ip4
+        if proto != IP_PROTOS.icmp:
+            sport = 20
+            dport = p[layer].sport
+        else:
+            sport = p[layer].id
+            dport = 0
+        pkts = self.create_stream_frag(self.pg1,
+                                       dst_addr,
+                                       sport,
+                                       dport,
+                                       data,
+                                       proto,
+                                       echo_reply=True)
+        self.pg1.add_stream(pkts)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        frags = self.pg0.get_capture(len(pkts))
+        p = self.reass_frags_and_verify(frags,
+                                        self.pg1.remote_ip4,
+                                        self.pg0.remote_ip4)
+        if proto != IP_PROTOS.icmp:
+            self.assertEqual(p[layer].sport, 20)
+            self.assertEqual(p[layer].dport, self.port_in)
+        else:
+            self.assertEqual(p[layer].id, self.port_in)
+        self.assertEqual(data, p[Raw].load)
+
+        reass = self.vapi.nat_reass_dump()
+        reass_n_end = len(reass)
+
+        self.assertEqual(reass_n_end - reass_n_start, 2)
+
+    def frag_in_order_in_plus_out(self, proto=IP_PROTOS.tcp):
+        layer = self.proto2layer(proto)
+
+        if proto == IP_PROTOS.tcp:
+            data = "A" * 4 + "B" * 16 + "C" * 3
+        else:
+            data = "A" * 16 + "B" * 16 + "C" * 3
+        self.port_in = random.randint(1025, 65535)
+
+        for i in range(2):
+            reass = self.vapi.nat_reass_dump()
+            reass_n_start = len(reass)
+
+            # out2in
+            pkts = self.create_stream_frag(self.pg0,
+                                           self.server_out_addr,
+                                           self.port_in,
+                                           self.server_out_port,
+                                           data,
+                                           proto)
+            self.pg0.add_stream(pkts)
+            self.pg_enable_capture(self.pg_interfaces)
+            self.pg_start()
+            frags = self.pg1.get_capture(len(pkts))
+            p = self.reass_frags_and_verify(frags,
+                                            self.pg0.remote_ip4,
+                                            self.server_in_addr)
+            if proto != IP_PROTOS.icmp:
+                self.assertEqual(p[layer].sport, self.port_in)
+                self.assertEqual(p[layer].dport, self.server_in_port)
+            else:
+                self.assertEqual(p[layer].id, self.port_in)
+            self.assertEqual(data, p[Raw].load)
+
+            # in2out
+            if proto != IP_PROTOS.icmp:
+                pkts = self.create_stream_frag(self.pg1,
+                                               self.pg0.remote_ip4,
+                                               self.server_in_port,
+                                               p[layer].sport,
+                                               data,
+                                               proto)
+            else:
+                pkts = self.create_stream_frag(self.pg1,
+                                               self.pg0.remote_ip4,
+                                               p[layer].id,
+                                               0,
+                                               data,
+                                               proto,
+                                               echo_reply=True)
+            self.pg1.add_stream(pkts)
+            self.pg_enable_capture(self.pg_interfaces)
+            self.pg_start()
+            frags = self.pg0.get_capture(len(pkts))
+            p = self.reass_frags_and_verify(frags,
+                                            self.server_out_addr,
+                                            self.pg0.remote_ip4)
+            if proto != IP_PROTOS.icmp:
+                self.assertEqual(p[layer].sport, self.server_out_port)
+                self.assertEqual(p[layer].dport, self.port_in)
+            else:
+                self.assertEqual(p[layer].id, self.port_in)
+            self.assertEqual(data, p[Raw].load)
+
+            reass = self.vapi.nat_reass_dump()
+            reass_n_end = len(reass)
+
+            self.assertEqual(reass_n_end - reass_n_start, 2)
+
+    def reass_hairpinning(self, proto=IP_PROTOS.tcp):
+        layer = self.proto2layer(proto)
+
+        if proto == IP_PROTOS.tcp:
+            data = "A" * 4 + "B" * 16 + "C" * 3
+        else:
+            data = "A" * 16 + "B" * 16 + "C" * 3
+
+        # send packet from host to server
+        pkts = self.create_stream_frag(self.pg0,
+                                       self.nat_addr,
+                                       self.host_in_port,
+                                       self.server_out_port,
+                                       data,
+                                       proto)
+        self.pg0.add_stream(pkts)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        frags = self.pg0.get_capture(len(pkts))
+        p = self.reass_frags_and_verify(frags,
+                                        self.nat_addr,
+                                        self.server.ip4)
+        if proto != IP_PROTOS.icmp:
+            self.assertNotEqual(p[layer].sport, self.host_in_port)
+            self.assertEqual(p[layer].dport, self.server_in_port)
+        else:
+            self.assertNotEqual(p[layer].id, self.host_in_port)
+        self.assertEqual(data, p[Raw].load)
+
+    def frag_out_of_order(self, proto=IP_PROTOS.tcp, dont_translate=False):
+        layer = self.proto2layer(proto)
+
+        if proto == IP_PROTOS.tcp:
+            data = "A" * 4 + "B" * 16 + "C" * 3
+        else:
+            data = "A" * 16 + "B" * 16 + "C" * 3
+        self.port_in = random.randint(1025, 65535)
+
+        for i in range(2):
+            # in2out
+            pkts = self.create_stream_frag(self.pg0,
+                                           self.pg1.remote_ip4,
+                                           self.port_in,
+                                           20,
+                                           data,
+                                           proto)
+            pkts.reverse()
+            self.pg0.add_stream(pkts)
+            self.pg_enable_capture(self.pg_interfaces)
+            self.pg_start()
+            frags = self.pg1.get_capture(len(pkts))
+            if not dont_translate:
+                p = self.reass_frags_and_verify(frags,
+                                                self.nat_addr,
+                                                self.pg1.remote_ip4)
+            else:
+                p = self.reass_frags_and_verify(frags,
+                                                self.pg0.remote_ip4,
+                                                self.pg1.remote_ip4)
+            if proto != IP_PROTOS.icmp:
+                if not dont_translate:
+                    self.assertEqual(p[layer].dport, 20)
+                    self.assertNotEqual(p[layer].sport, self.port_in)
+                else:
+                    self.assertEqual(p[layer].sport, self.port_in)
+            else:
+                if not dont_translate:
+                    self.assertNotEqual(p[layer].id, self.port_in)
+                else:
+                    self.assertEqual(p[layer].id, self.port_in)
+            self.assertEqual(data, p[Raw].load)
+
+            # out2in
+            if not dont_translate:
+                dst_addr = self.nat_addr
+            else:
+                dst_addr = self.pg0.remote_ip4
+            if proto != IP_PROTOS.icmp:
+                sport = 20
+                dport = p[layer].sport
+            else:
+                sport = p[layer].id
+                dport = 0
+            pkts = self.create_stream_frag(self.pg1,
+                                           dst_addr,
+                                           sport,
+                                           dport,
+                                           data,
+                                           proto,
+                                           echo_reply=True)
+            pkts.reverse()
+            self.pg1.add_stream(pkts)
+            self.pg_enable_capture(self.pg_interfaces)
+            self.pg_start()
+            frags = self.pg0.get_capture(len(pkts))
+            p = self.reass_frags_and_verify(frags,
+                                            self.pg1.remote_ip4,
+                                            self.pg0.remote_ip4)
+            if proto != IP_PROTOS.icmp:
+                self.assertEqual(p[layer].sport, 20)
+                self.assertEqual(p[layer].dport, self.port_in)
+            else:
+                self.assertEqual(p[layer].id, self.port_in)
+            self.assertEqual(data, p[Raw].load)
+
+    def frag_out_of_order_in_plus_out(self, proto=IP_PROTOS.tcp):
+        layer = self.proto2layer(proto)
+
+        if proto == IP_PROTOS.tcp:
+            data = "A" * 4 + "B" * 16 + "C" * 3
+        else:
+            data = "A" * 16 + "B" * 16 + "C" * 3
+        self.port_in = random.randint(1025, 65535)
+
+        for i in range(2):
+            # out2in
+            pkts = self.create_stream_frag(self.pg0,
+                                           self.server_out_addr,
+                                           self.port_in,
+                                           self.server_out_port,
+                                           data,
+                                           proto)
+            pkts.reverse()
+            self.pg0.add_stream(pkts)
+            self.pg_enable_capture(self.pg_interfaces)
+            self.pg_start()
+            frags = self.pg1.get_capture(len(pkts))
+            p = self.reass_frags_and_verify(frags,
+                                            self.pg0.remote_ip4,
+                                            self.server_in_addr)
+            if proto != IP_PROTOS.icmp:
+                self.assertEqual(p[layer].dport, self.server_in_port)
+                self.assertEqual(p[layer].sport, self.port_in)
+                self.assertEqual(p[layer].dport, self.server_in_port)
+            else:
+                self.assertEqual(p[layer].id, self.port_in)
+            self.assertEqual(data, p[Raw].load)
+
+            # in2out
+            if proto != IP_PROTOS.icmp:
+                pkts = self.create_stream_frag(self.pg1,
+                                               self.pg0.remote_ip4,
+                                               self.server_in_port,
+                                               p[layer].sport,
+                                               data,
+                                               proto)
+            else:
+                pkts = self.create_stream_frag(self.pg1,
+                                               self.pg0.remote_ip4,
+                                               p[layer].id,
+                                               0,
+                                               data,
+                                               proto,
+                                               echo_reply=True)
+            pkts.reverse()
+            self.pg1.add_stream(pkts)
+            self.pg_enable_capture(self.pg_interfaces)
+            self.pg_start()
+            frags = self.pg0.get_capture(len(pkts))
+            p = self.reass_frags_and_verify(frags,
+                                            self.server_out_addr,
+                                            self.pg0.remote_ip4)
+            if proto != IP_PROTOS.icmp:
+                self.assertEqual(p[layer].sport, self.server_out_port)
+                self.assertEqual(p[layer].dport, self.port_in)
+            else:
+                self.assertEqual(p[layer].id, self.port_in)
+            self.assertEqual(data, p[Raw].load)
+
+
+class TestNAT44(MethodHolder):
+    """ NAT44 Test Cases """
+
+    @classmethod
+    def setUpClass(cls):
+        super(TestNAT44, cls).setUpClass()
+        cls.vapi.cli("set log class nat level debug")
+
+        try:
+            cls.tcp_port_in = 6303
+            cls.tcp_port_out = 6303
+            cls.udp_port_in = 6304
+            cls.udp_port_out = 6304
+            cls.icmp_id_in = 6305
+            cls.icmp_id_out = 6305
+            cls.nat_addr = '10.0.0.3'
+            cls.nat_addr_n = socket.inet_pton(socket.AF_INET, cls.nat_addr)
+            cls.ipfix_src_port = 4739
+            cls.ipfix_domain_id = 1
+            cls.tcp_external_port = 80
+
+            cls.create_pg_interfaces(range(10))
+            cls.interfaces = list(cls.pg_interfaces[0:4])
+
+            for i in cls.interfaces:
+                i.admin_up()
+                i.config_ip4()
+                i.resolve_arp()
+
+            cls.pg0.generate_remote_hosts(3)
+            cls.pg0.configure_ipv4_neighbors()
+
+            cls.pg1.generate_remote_hosts(1)
+            cls.pg1.configure_ipv4_neighbors()
+
+            cls.overlapping_interfaces = list(list(cls.pg_interfaces[4:7]))
+            cls.vapi.ip_table_add_del(10, is_add=1)
+            cls.vapi.ip_table_add_del(20, is_add=1)
+
+            cls.pg4._local_ip4 = "172.16.255.1"
+            cls.pg4._local_ip4n = socket.inet_pton(socket.AF_INET, i.local_ip4)
+            cls.pg4._remote_hosts[0]._ip4 = "172.16.255.2"
+            cls.pg4.set_table_ip4(10)
+            cls.pg5._local_ip4 = "172.17.255.3"
+            cls.pg5._local_ip4n = socket.inet_pton(socket.AF_INET, i.local_ip4)
+            cls.pg5._remote_hosts[0]._ip4 = "172.17.255.4"
+            cls.pg5.set_table_ip4(10)
+            cls.pg6._local_ip4 = "172.16.255.1"
+            cls.pg6._local_ip4n = socket.inet_pton(socket.AF_INET, i.local_ip4)
+            cls.pg6._remote_hosts[0]._ip4 = "172.16.255.2"
+            cls.pg6.set_table_ip4(20)
+            for i in cls.overlapping_interfaces:
+                i.config_ip4()
+                i.admin_up()
+                i.resolve_arp()
+
+            cls.pg7.admin_up()
             cls.pg8.admin_up()
 
             cls.pg9.generate_remote_hosts(2)
@@ -962,201 +1509,85 @@ class TestNAT44(MethodHolder):
             super(TestNAT44, cls).tearDownClass()
             raise
 
-    def clear_nat44(self):
-        """
-        Clear NAT44 configuration.
-        """
-        # I found no elegant way to do this
-        self.vapi.ip_add_del_route(dst_address=self.pg7.remote_ip4n,
-                                   dst_address_length=32,
-                                   next_hop_address=self.pg7.remote_ip4n,
-                                   next_hop_sw_if_index=self.pg7.sw_if_index,
-                                   is_add=0)
-        self.vapi.ip_add_del_route(dst_address=self.pg8.remote_ip4n,
-                                   dst_address_length=32,
-                                   next_hop_address=self.pg8.remote_ip4n,
-                                   next_hop_sw_if_index=self.pg8.sw_if_index,
-                                   is_add=0)
-
-        for intf in [self.pg7, self.pg8]:
-            neighbors = self.vapi.ip_neighbor_dump(intf.sw_if_index)
-            for n in neighbors:
-                self.vapi.ip_neighbor_add_del(intf.sw_if_index,
-                                              n.mac_address,
-                                              n.ip_address,
-                                              is_add=0)
+    def test_dynamic(self):
+        """ NAT44 dynamic translation test """
+        self.nat44_add_address(self.nat_addr)
+        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
+                                                  is_inside=0)
 
-        if self.pg7.has_ip4_config:
-            self.pg7.unconfig_ip4()
+        # in2out
+        tcpn = self.statistics.get_counter(
+            '/err/nat44-in2out-slowpath/TCP packets')
+        udpn = self.statistics.get_counter(
+            '/err/nat44-in2out-slowpath/UDP packets')
+        icmpn = self.statistics.get_counter(
+            '/err/nat44-in2out-slowpath/ICMP packets')
+        totaln = self.statistics.get_counter(
+            '/err/nat44-in2out-slowpath/good in2out packets processed')
 
-        self.vapi.nat44_forwarding_enable_disable(0)
+        pkts = self.create_stream_in(self.pg0, self.pg1)
+        self.pg0.add_stream(pkts)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg1.get_capture(len(pkts))
+        self.verify_capture_out(capture)
 
-        interfaces = self.vapi.nat44_interface_addr_dump()
-        for intf in interfaces:
-            self.vapi.nat44_add_interface_addr(intf.sw_if_index,
-                                               twice_nat=intf.twice_nat,
-                                               is_add=0)
+        err = self.statistics.get_counter(
+            '/err/nat44-in2out-slowpath/TCP packets')
+        self.assertEqual(err - tcpn, 1)
+        err = self.statistics.get_counter(
+            '/err/nat44-in2out-slowpath/UDP packets')
+        self.assertEqual(err - udpn, 1)
+        err = self.statistics.get_counter(
+            '/err/nat44-in2out-slowpath/ICMP packets')
+        self.assertEqual(err - icmpn, 1)
+        err = self.statistics.get_counter(
+            '/err/nat44-in2out-slowpath/good in2out packets processed')
+        self.assertEqual(err - totaln, 3)
 
-        self.vapi.nat_ipfix(enable=0, src_port=self.ipfix_src_port,
-                            domain_id=self.ipfix_domain_id)
-        self.ipfix_src_port = 4739
-        self.ipfix_domain_id = 1
+        # out2in
+        tcpn = self.statistics.get_counter('/err/nat44-out2in/TCP packets')
+        udpn = self.statistics.get_counter('/err/nat44-out2in/UDP packets')
+        icmpn = self.statistics.get_counter('/err/nat44-out2in/ICMP packets')
+        totaln = self.statistics.get_counter(
+            '/err/nat44-out2in/good out2in packets processed')
 
-        interfaces = self.vapi.nat44_interface_dump()
-        for intf in interfaces:
-            if intf.is_inside > 1:
-                self.vapi.nat44_interface_add_del_feature(intf.sw_if_index,
-                                                          0,
-                                                          is_add=0)
-            self.vapi.nat44_interface_add_del_feature(intf.sw_if_index,
-                                                      intf.is_inside,
-                                                      is_add=0)
+        pkts = self.create_stream_out(self.pg1)
+        self.pg1.add_stream(pkts)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg0.get_capture(len(pkts))
+        self.verify_capture_in(capture, self.pg0)
 
-        interfaces = self.vapi.nat44_interface_output_feature_dump()
-        for intf in interfaces:
-            self.vapi.nat44_interface_add_del_output_feature(intf.sw_if_index,
-                                                             intf.is_inside,
-                                                             is_add=0)
+        err = self.statistics.get_counter('/err/nat44-out2in/TCP packets')
+        self.assertEqual(err - tcpn, 1)
+        err = self.statistics.get_counter('/err/nat44-out2in/UDP packets')
+        self.assertEqual(err - udpn, 1)
+        err = self.statistics.get_counter('/err/nat44-out2in/ICMP packets')
+        self.assertEqual(err - icmpn, 1)
+        err = self.statistics.get_counter(
+            '/err/nat44-out2in/good out2in packets processed')
+        self.assertEqual(err - totaln, 3)
+
+        users = self.statistics.get_counter('/nat44/total-users')
+        self.assertEqual(users[0][0], 1)
+        sessions = self.statistics.get_counter('/nat44/total-sessions')
+        self.assertEqual(sessions[0][0], 3)
 
-        static_mappings = self.vapi.nat44_static_mapping_dump()
-        for sm in static_mappings:
-            self.vapi.nat44_add_del_static_mapping(
-                sm.local_ip_address,
-                sm.external_ip_address,
-                local_port=sm.local_port,
-                external_port=sm.external_port,
-                addr_only=sm.addr_only,
-                vrf_id=sm.vrf_id,
-                protocol=sm.protocol,
-                twice_nat=sm.twice_nat,
-                out2in_only=sm.out2in_only,
-                tag=sm.tag,
-                external_sw_if_index=sm.external_sw_if_index,
-                is_add=0)
+    def test_dynamic_icmp_errors_in2out_ttl_1(self):
+        """ NAT44 handling of client packets with TTL=1 """
 
-        lb_static_mappings = self.vapi.nat44_lb_static_mapping_dump()
-        for lb_sm in lb_static_mappings:
-            self.vapi.nat44_add_del_lb_static_mapping(
-                lb_sm.external_addr,
-                lb_sm.external_port,
-                lb_sm.protocol,
-                vrf_id=lb_sm.vrf_id,
-                twice_nat=lb_sm.twice_nat,
-                out2in_only=lb_sm.out2in_only,
-                tag=lb_sm.tag,
-                is_add=0,
-                local_num=0,
-                locals=[])
+        self.nat44_add_address(self.nat_addr)
+        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
+                                                  is_inside=0)
 
-        identity_mappings = self.vapi.nat44_identity_mapping_dump()
-        for id_m in identity_mappings:
-            self.vapi.nat44_add_del_identity_mapping(
-                addr_only=id_m.addr_only,
-                ip=id_m.ip_address,
-                port=id_m.port,
-                sw_if_index=id_m.sw_if_index,
-                vrf_id=id_m.vrf_id,
-                protocol=id_m.protocol,
-                is_add=0)
-
-        adresses = self.vapi.nat44_address_dump()
-        for addr in adresses:
-            self.vapi.nat44_add_del_address_range(addr.ip_address,
-                                                  addr.ip_address,
-                                                  twice_nat=addr.twice_nat,
-                                                  is_add=0)
-
-        self.vapi.nat_set_reass()
-        self.vapi.nat_set_reass(is_ip6=1)
-
-    def nat44_add_static_mapping(self, local_ip, external_ip='0.0.0.0',
-                                 local_port=0, external_port=0, vrf_id=0,
-                                 is_add=1, external_sw_if_index=0xFFFFFFFF,
-                                 proto=0, twice_nat=0, out2in_only=0, tag=""):
-        """
-        Add/delete NAT44 static mapping
-
-        :param local_ip: Local IP address
-        :param external_ip: External IP address
-        :param local_port: Local port number (Optional)
-        :param external_port: External port number (Optional)
-        :param vrf_id: VRF ID (Default 0)
-        :param is_add: 1 if add, 0 if delete (Default add)
-        :param external_sw_if_index: External interface instead of IP address
-        :param proto: IP protocol (Mandatory if port specified)
-        :param twice_nat: 1 if translate external host address and port
-        :param out2in_only: if 1 rule is matching only out2in direction
-        :param tag: Opaque string tag
-        """
-        addr_only = 1
-        if local_port and external_port:
-            addr_only = 0
-        l_ip = socket.inet_pton(socket.AF_INET, local_ip)
-        e_ip = socket.inet_pton(socket.AF_INET, external_ip)
-        self.vapi.nat44_add_del_static_mapping(
-            l_ip,
-            e_ip,
-            external_sw_if_index,
-            local_port,
-            external_port,
-            addr_only,
-            vrf_id,
-            proto,
-            twice_nat,
-            out2in_only,
-            tag,
-            is_add)
-
-    def nat44_add_address(self, ip, is_add=1, vrf_id=0xFFFFFFFF, twice_nat=0):
-        """
-        Add/delete NAT44 address
-
-        :param ip: IP address
-        :param is_add: 1 if add, 0 if delete (Default add)
-        :param twice_nat: twice NAT address for extenal hosts
-        """
-        nat_addr = socket.inet_pton(socket.AF_INET, ip)
-        self.vapi.nat44_add_del_address_range(nat_addr, nat_addr, is_add,
-                                              vrf_id=vrf_id,
-                                              twice_nat=twice_nat)
-
-    def test_dynamic(self):
-        """ NAT44 dynamic translation test """
-
-        self.nat44_add_address(self.nat_addr)
-        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
-        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
-                                                  is_inside=0)
-
-        # in2out
-        pkts = self.create_stream_in(self.pg0, self.pg1)
-        self.pg0.add_stream(pkts)
-        self.pg_enable_capture(self.pg_interfaces)
-        self.pg_start()
-        capture = self.pg1.get_capture(len(pkts))
-        self.verify_capture_out(capture)
-
-        # out2in
-        pkts = self.create_stream_out(self.pg1)
-        self.pg1.add_stream(pkts)
-        self.pg_enable_capture(self.pg_interfaces)
-        self.pg_start()
-        capture = self.pg0.get_capture(len(pkts))
-        self.verify_capture_in(capture, self.pg0)
-
-    def test_dynamic_icmp_errors_in2out_ttl_1(self):
-        """ NAT44 handling of client packets with TTL=1 """
-
-        self.nat44_add_address(self.nat_addr)
-        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
-        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
-                                                  is_inside=0)
-
-        # Client side - generate traffic
-        pkts = self.create_stream_in(self.pg0, self.pg1, ttl=1)
-        self.pg0.add_stream(pkts)
-        self.pg_enable_capture(self.pg_interfaces)
-        self.pg_start()
+        # Client side - generate traffic
+        pkts = self.create_stream_in(self.pg0, self.pg1, ttl=1)
+        self.pg0.add_stream(pkts)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
 
         # Client side - verify ICMP type 11 packets
         capture = self.pg0.get_capture(len(pkts))
@@ -1267,7 +1698,6 @@ class TestNAT44(MethodHolder):
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
         capture = self.pg1.get_capture(len(pkts))
-        self.assertEqual(1, len(capture))
         packet = capture[0]
         try:
             self.assertEqual(packet[IP].src, self.pg1.local_ip4)
@@ -1295,7 +1725,7 @@ class TestNAT44(MethodHolder):
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
         capture = self.pg0.get_capture(1)
-        self.verify_capture_in(capture, self.pg0, packet_num=1)
+        self.verify_capture_in(capture, self.pg0)
         self.assert_equal(capture[0][IP].proto, IP_PROTOS.icmp)
 
         # in2out
@@ -1306,7 +1736,7 @@ class TestNAT44(MethodHolder):
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
         capture = self.pg1.get_capture(1)
-        self.verify_capture_out(capture, same_port=True, packet_num=1)
+        self.verify_capture_out(capture, same_port=True)
         self.assert_equal(capture[0][IP].proto, IP_PROTOS.icmp)
 
     def test_forwarding(self):
@@ -1323,7 +1753,7 @@ class TestNAT44(MethodHolder):
                                                external_ip=alias_ip)
 
         try:
-            # in2out - static mapping match
+            # static mapping match
 
             pkts = self.create_stream_out(self.pg1)
             self.pg1.add_stream(pkts)
@@ -1339,7 +1769,7 @@ class TestNAT44(MethodHolder):
             capture = self.pg1.get_capture(len(pkts))
             self.verify_capture_out(capture, same_port=True)
 
-            # in2out - no static mapping match
+            # no static mapping match
 
             host0 = self.pg0.remote_hosts[0]
             self.pg0.remote_hosts[0] = self.pg0.remote_hosts[1]
@@ -1511,138 +1941,6 @@ class TestNAT44(MethodHolder):
         capture = self.pg1.get_capture(len(pkts))
         self.verify_capture_out(capture)
 
-    def test_static_with_port_out2(self):
-        """ 1:1 NAPT symmetrical rule """
-
-        external_port = 80
-        local_port = 8080
-
-        self.vapi.nat44_forwarding_enable_disable(1)
-        self.nat44_add_static_mapping(self.pg0.remote_ip4, self.nat_addr,
-                                      local_port, external_port,
-                                      proto=IP_PROTOS.tcp, out2in_only=1)
-        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
-        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
-                                                  is_inside=0)
-
-        # from client to service
-        p = (Ether(src=self.pg1.remote_mac, dst=self.pg1.local_mac) /
-             IP(src=self.pg1.remote_ip4, dst=self.nat_addr) /
-             TCP(sport=12345, dport=external_port))
-        self.pg1.add_stream(p)
-        self.pg_enable_capture(self.pg_interfaces)
-        self.pg_start()
-        capture = self.pg0.get_capture(1)
-        p = capture[0]
-        server = None
-        try:
-            ip = p[IP]
-            tcp = p[TCP]
-            self.assertEqual(ip.dst, self.pg0.remote_ip4)
-            self.assertEqual(tcp.dport, local_port)
-            self.check_tcp_checksum(p)
-            self.check_ip_checksum(p)
-        except:
-            self.logger.error(ppp("Unexpected or invalid packet:", p))
-            raise
-
-        # ICMP error
-        p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
-             IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4) /
-             ICMP(type=11) / capture[0][IP])
-        self.pg0.add_stream(p)
-        self.pg_enable_capture(self.pg_interfaces)
-        self.pg_start()
-        capture = self.pg1.get_capture(1)
-        p = capture[0]
-        try:
-            self.assertEqual(p[IP].src, self.nat_addr)
-            inner = p[IPerror]
-            self.assertEqual(inner.dst, self.nat_addr)
-            self.assertEqual(inner[TCPerror].dport, external_port)
-        except:
-            self.logger.error(ppp("Unexpected or invalid packet:", p))
-            raise
-
-        # from service back to client
-        p = (Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac) /
-             IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4) /
-             TCP(sport=local_port, dport=12345))
-        self.pg0.add_stream(p)
-        self.pg_enable_capture(self.pg_interfaces)
-        self.pg_start()
-        capture = self.pg1.get_capture(1)
-        p = capture[0]
-        try:
-            ip = p[IP]
-            tcp = p[TCP]
-            self.assertEqual(ip.src, self.nat_addr)
-            self.assertEqual(tcp.sport, external_port)
-            self.check_tcp_checksum(p)
-            self.check_ip_checksum(p)
-        except:
-            self.logger.error(ppp("Unexpected or invalid packet:", p))
-            raise
-
-        # ICMP error
-        p = (Ether(dst=self.pg1.local_mac, src=self.pg1.remote_mac) /
-             IP(src=self.pg1.remote_ip4, dst=self.nat_addr) /
-             ICMP(type=11) / capture[0][IP])
-        self.pg1.add_stream(p)
-        self.pg_enable_capture(self.pg_interfaces)
-        self.pg_start()
-        capture = self.pg0.get_capture(1)
-        p = capture[0]
-        try:
-            self.assertEqual(p[IP].dst, self.pg0.remote_ip4)
-            inner = p[IPerror]
-            self.assertEqual(inner.src, self.pg0.remote_ip4)
-            self.assertEqual(inner[TCPerror].sport, local_port)
-        except:
-            self.logger.error(ppp("Unexpected or invalid packet:", p))
-            raise
-
-        # from client to server (no translation)
-        p = (Ether(src=self.pg1.remote_mac, dst=self.pg1.local_mac) /
-             IP(src=self.pg1.remote_ip4, dst=self.pg0.remote_ip4) /
-             TCP(sport=12346, dport=local_port))
-        self.pg1.add_stream(p)
-        self.pg_enable_capture(self.pg_interfaces)
-        self.pg_start()
-        capture = self.pg0.get_capture(1)
-        p = capture[0]
-        server = None
-        try:
-            ip = p[IP]
-            tcp = p[TCP]
-            self.assertEqual(ip.dst, self.pg0.remote_ip4)
-            self.assertEqual(tcp.dport, local_port)
-            self.check_tcp_checksum(p)
-            self.check_ip_checksum(p)
-        except:
-            self.logger.error(ppp("Unexpected or invalid packet:", p))
-            raise
-
-        # from service back to client (no translation)
-        p = (Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac) /
-             IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4) /
-             TCP(sport=local_port, dport=12346))
-        self.pg0.add_stream(p)
-        self.pg_enable_capture(self.pg_interfaces)
-        self.pg_start()
-        capture = self.pg1.get_capture(1)
-        p = capture[0]
-        try:
-            ip = p[IP]
-            tcp = p[TCP]
-            self.assertEqual(ip.src, self.pg0.remote_ip4)
-            self.assertEqual(tcp.sport, local_port)
-            self.check_tcp_checksum(p)
-            self.check_ip_checksum(p)
-        except:
-            self.logger.error(ppp("Unexpected or invalid packet:", p))
-            raise
-
     def test_static_vrf_aware(self):
         """ 1:1 NAT VRF awareness """
 
@@ -1731,253 +2029,30 @@ class TestNAT44(MethodHolder):
             self.assertEqual(ip.src, self.pg1.remote_ip4)
             self.assertEqual(tcp.dport, 56789)
             self.assertEqual(tcp.sport, 12345)
-            self.check_tcp_checksum(p)
-            self.check_ip_checksum(p)
+            self.assert_packet_checksums_valid(p)
         except:
             self.logger.error(ppp("Unexpected or invalid packet:", p))
             raise
 
-    def test_static_lb(self):
-        """ NAT44 local service load balancing """
-        external_addr_n = socket.inet_pton(socket.AF_INET, self.nat_addr)
-        external_port = 80
-        local_port = 8080
-        server1 = self.pg0.remote_hosts[0]
-        server2 = self.pg0.remote_hosts[1]
+        sessions = self.vapi.nat44_user_session_dump(self.pg0.remote_ip4n, 0)
+        self.assertEqual(len(sessions), 0)
+        self.vapi.nat44_add_del_identity_mapping(ip=self.pg0.remote_ip4n,
+                                                 vrf_id=1)
+        identity_mappings = self.vapi.nat44_identity_mapping_dump()
+        self.assertEqual(len(identity_mappings), 2)
 
-        locals = [{'addr': server1.ip4n,
-                   'port': local_port,
-                   'probability': 70},
-                  {'addr': server2.ip4n,
-                   'port': local_port,
-                   'probability': 30}]
+    def test_multiple_inside_interfaces(self):
+        """ NAT44 multiple non-overlapping address space inside interfaces """
 
         self.nat44_add_address(self.nat_addr)
-        self.vapi.nat44_add_del_lb_static_mapping(external_addr_n,
-                                                  external_port,
-                                                  IP_PROTOS.tcp,
-                                                  local_num=len(locals),
-                                                  locals=locals)
         self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
-        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
+        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg3.sw_if_index,
                                                   is_inside=0)
 
-        # from client to service
-        p = (Ether(src=self.pg1.remote_mac, dst=self.pg1.local_mac) /
-             IP(src=self.pg1.remote_ip4, dst=self.nat_addr) /
-             TCP(sport=12345, dport=external_port))
-        self.pg1.add_stream(p)
-        self.pg_enable_capture(self.pg_interfaces)
-        self.pg_start()
-        capture = self.pg0.get_capture(1)
-        p = capture[0]
-        server = None
-        try:
-            ip = p[IP]
-            tcp = p[TCP]
-            self.assertIn(ip.dst, [server1.ip4, server2.ip4])
-            if ip.dst == server1.ip4:
-                server = server1
-            else:
-                server = server2
-            self.assertEqual(tcp.dport, local_port)
-            self.check_tcp_checksum(p)
-            self.check_ip_checksum(p)
-        except:
-            self.logger.error(ppp("Unexpected or invalid packet:", p))
-            raise
-
-        # from service back to client
-        p = (Ether(src=server.mac, dst=self.pg0.local_mac) /
-             IP(src=server.ip4, dst=self.pg1.remote_ip4) /
-             TCP(sport=local_port, dport=12345))
-        self.pg0.add_stream(p)
-        self.pg_enable_capture(self.pg_interfaces)
-        self.pg_start()
-        capture = self.pg1.get_capture(1)
-        p = capture[0]
-        try:
-            ip = p[IP]
-            tcp = p[TCP]
-            self.assertEqual(ip.src, self.nat_addr)
-            self.assertEqual(tcp.sport, external_port)
-            self.check_tcp_checksum(p)
-            self.check_ip_checksum(p)
-        except:
-            self.logger.error(ppp("Unexpected or invalid packet:", p))
-            raise
-
-    @unittest.skipUnless(running_extended_tests(), "part of extended tests")
-    def test_static_lb_multi_clients(self):
-        """ NAT44 local service load balancing - multiple clients"""
-
-        external_addr_n = socket.inet_pton(socket.AF_INET, self.nat_addr)
-        external_port = 80
-        local_port = 8080
-        server1 = self.pg0.remote_hosts[0]
-        server2 = self.pg0.remote_hosts[1]
-
-        locals = [{'addr': server1.ip4n,
-                   'port': local_port,
-                   'probability': 90},
-                  {'addr': server2.ip4n,
-                   'port': local_port,
-                   'probability': 10}]
-
-        self.nat44_add_address(self.nat_addr)
-        self.vapi.nat44_add_del_lb_static_mapping(external_addr_n,
-                                                  external_port,
-                                                  IP_PROTOS.tcp,
-                                                  local_num=len(locals),
-                                                  locals=locals)
-        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
-        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
-                                                  is_inside=0)
-
-        server1_n = 0
-        server2_n = 0
-        clients = ip4_range(self.pg1.remote_ip4, 10, 50)
-        pkts = []
-        for client in clients:
-            p = (Ether(src=self.pg1.remote_mac, dst=self.pg1.local_mac) /
-                 IP(src=client, dst=self.nat_addr) /
-                 TCP(sport=12345, dport=external_port))
-            pkts.append(p)
-        self.pg1.add_stream(pkts)
-        self.pg_enable_capture(self.pg_interfaces)
-        self.pg_start()
-        capture = self.pg0.get_capture(len(pkts))
-        for p in capture:
-            if p[IP].dst == server1.ip4:
-                server1_n += 1
-            else:
-                server2_n += 1
-        self.assertTrue(server1_n > server2_n)
-
-    def test_static_lb_2(self):
-        """ NAT44 local service load balancing (asymmetrical rule) """
-        external_addr_n = socket.inet_pton(socket.AF_INET, self.nat_addr)
-        external_port = 80
-        local_port = 8080
-        server1 = self.pg0.remote_hosts[0]
-        server2 = self.pg0.remote_hosts[1]
-
-        locals = [{'addr': server1.ip4n,
-                   'port': local_port,
-                   'probability': 70},
-                  {'addr': server2.ip4n,
-                   'port': local_port,
-                   'probability': 30}]
-
-        self.vapi.nat44_forwarding_enable_disable(1)
-        self.vapi.nat44_add_del_lb_static_mapping(external_addr_n,
-                                                  external_port,
-                                                  IP_PROTOS.tcp,
-                                                  out2in_only=1,
-                                                  local_num=len(locals),
-                                                  locals=locals)
-        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
-        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
-                                                  is_inside=0)
-
-        # from client to service
-        p = (Ether(src=self.pg1.remote_mac, dst=self.pg1.local_mac) /
-             IP(src=self.pg1.remote_ip4, dst=self.nat_addr) /
-             TCP(sport=12345, dport=external_port))
-        self.pg1.add_stream(p)
-        self.pg_enable_capture(self.pg_interfaces)
-        self.pg_start()
-        capture = self.pg0.get_capture(1)
-        p = capture[0]
-        server = None
-        try:
-            ip = p[IP]
-            tcp = p[TCP]
-            self.assertIn(ip.dst, [server1.ip4, server2.ip4])
-            if ip.dst == server1.ip4:
-                server = server1
-            else:
-                server = server2
-            self.assertEqual(tcp.dport, local_port)
-            self.check_tcp_checksum(p)
-            self.check_ip_checksum(p)
-        except:
-            self.logger.error(ppp("Unexpected or invalid packet:", p))
-            raise
-
-        # from service back to client
-        p = (Ether(src=server.mac, dst=self.pg0.local_mac) /
-             IP(src=server.ip4, dst=self.pg1.remote_ip4) /
-             TCP(sport=local_port, dport=12345))
-        self.pg0.add_stream(p)
-        self.pg_enable_capture(self.pg_interfaces)
-        self.pg_start()
-        capture = self.pg1.get_capture(1)
-        p = capture[0]
-        try:
-            ip = p[IP]
-            tcp = p[TCP]
-            self.assertEqual(ip.src, self.nat_addr)
-            self.assertEqual(tcp.sport, external_port)
-            self.check_tcp_checksum(p)
-            self.check_ip_checksum(p)
-        except:
-            self.logger.error(ppp("Unexpected or invalid packet:", p))
-            raise
-
-        # from client to server (no translation)
-        p = (Ether(src=self.pg1.remote_mac, dst=self.pg1.local_mac) /
-             IP(src=self.pg1.remote_ip4, dst=server1.ip4) /
-             TCP(sport=12346, dport=local_port))
-        self.pg1.add_stream(p)
-        self.pg_enable_capture(self.pg_interfaces)
-        self.pg_start()
-        capture = self.pg0.get_capture(1)
-        p = capture[0]
-        server = None
-        try:
-            ip = p[IP]
-            tcp = p[TCP]
-            self.assertEqual(ip.dst, server1.ip4)
-            self.assertEqual(tcp.dport, local_port)
-            self.check_tcp_checksum(p)
-            self.check_ip_checksum(p)
-        except:
-            self.logger.error(ppp("Unexpected or invalid packet:", p))
-            raise
-
-        # from service back to client (no translation)
-        p = (Ether(src=server1.mac, dst=self.pg0.local_mac) /
-             IP(src=server1.ip4, dst=self.pg1.remote_ip4) /
-             TCP(sport=local_port, dport=12346))
-        self.pg0.add_stream(p)
-        self.pg_enable_capture(self.pg_interfaces)
-        self.pg_start()
-        capture = self.pg1.get_capture(1)
-        p = capture[0]
-        try:
-            ip = p[IP]
-            tcp = p[TCP]
-            self.assertEqual(ip.src, server1.ip4)
-            self.assertEqual(tcp.sport, local_port)
-            self.check_tcp_checksum(p)
-            self.check_ip_checksum(p)
-        except:
-            self.logger.error(ppp("Unexpected or invalid packet:", p))
-            raise
-
-    def test_multiple_inside_interfaces(self):
-        """ NAT44 multiple non-overlapping address space inside interfaces """
-
-        self.nat44_add_address(self.nat_addr)
-        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
-        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index)
-        self.vapi.nat44_interface_add_del_feature(self.pg3.sw_if_index,
-                                                  is_inside=0)
-
-        # between two NAT44 inside interfaces (no translation)
-        pkts = self.create_stream_in(self.pg0, self.pg1)
-        self.pg0.add_stream(pkts)
+        # between two NAT44 inside interfaces (no translation)
+        pkts = self.create_stream_in(self.pg0, self.pg1)
+        self.pg0.add_stream(pkts)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
         capture = self.pg1.get_capture(len(pkts))
@@ -2135,7 +2210,7 @@ class TestNAT44(MethodHolder):
 
         # general user and session dump verifications
         users = self.vapi.nat44_user_dump()
-        self.assertTrue(len(users) >= 3)
+        self.assertGreaterEqual(len(users), 3)
         addresses = self.vapi.nat44_address_dump()
         self.assertEqual(len(addresses), 1)
         for user in users:
@@ -2147,10 +2222,11 @@ class TestNAT44(MethodHolder):
                 self.assertTrue(session.protocol in
                                 [IP_PROTOS.tcp, IP_PROTOS.udp,
                                  IP_PROTOS.icmp])
+                self.assertFalse(session.ext_host_valid)
 
         # pg4 session dump
         sessions = self.vapi.nat44_user_session_dump(self.pg4.remote_ip4n, 10)
-        self.assertTrue(len(sessions) >= 4)
+        self.assertGreaterEqual(len(sessions), 4)
         for session in sessions:
             self.assertFalse(session.is_static)
             self.assertEqual(session.inside_ip_address[0:4],
@@ -2160,7 +2236,7 @@ class TestNAT44(MethodHolder):
 
         # pg6 session dump
         sessions = self.vapi.nat44_user_session_dump(self.pg6.remote_ip4n, 20)
-        self.assertTrue(len(sessions) >= 3)
+        self.assertGreaterEqual(len(sessions), 3)
         for session in sessions:
             self.assertTrue(session.is_static)
             self.assertEqual(session.inside_ip_address[0:4],
@@ -2206,7 +2282,7 @@ class TestNAT44(MethodHolder):
             self.assertEqual(ip.dst, server.ip4)
             self.assertNotEqual(tcp.sport, host_in_port)
             self.assertEqual(tcp.dport, server_in_port)
-            self.check_tcp_checksum(p)
+            self.assert_packet_checksums_valid(p)
             host_out_port = tcp.sport
         except:
             self.logger.error(ppp("Unexpected or invalid packet:", p))
@@ -2228,7 +2304,7 @@ class TestNAT44(MethodHolder):
             self.assertEqual(ip.dst, host.ip4)
             self.assertEqual(tcp.sport, server_out_port)
             self.assertEqual(tcp.dport, host_in_port)
-            self.check_tcp_checksum(p)
+            self.assert_packet_checksums_valid(p)
         except:
             self.logger.error(ppp("Unexpected or invalid packet:", p))
             raise
@@ -2279,7 +2355,7 @@ class TestNAT44(MethodHolder):
                     self.assertNotEqual(packet[TCP].sport, self.tcp_port_in)
                     self.assertEqual(packet[TCP].dport, server_tcp_port)
                     self.tcp_port_out = packet[TCP].sport
-                    self.check_tcp_checksum(packet)
+                    self.assert_packet_checksums_valid(packet)
                 elif packet.haslayer(UDP):
                     self.assertNotEqual(packet[UDP].sport, self.udp_port_in)
                     self.assertEqual(packet[UDP].dport, server_udp_port)
@@ -2316,7 +2392,7 @@ class TestNAT44(MethodHolder):
                 if packet.haslayer(TCP):
                     self.assertEqual(packet[TCP].dport, self.tcp_port_in)
                     self.assertEqual(packet[TCP].sport, server_tcp_port)
-                    self.check_tcp_checksum(packet)
+                    self.assert_packet_checksums_valid(packet)
                 elif packet.haslayer(UDP):
                     self.assertEqual(packet[UDP].dport, self.udp_port_in)
                     self.assertEqual(packet[UDP].sport, server_udp_port)
@@ -2352,7 +2428,7 @@ class TestNAT44(MethodHolder):
                     self.assertEqual(packet[TCP].sport, self.tcp_port_in)
                     self.assertEqual(packet[TCP].dport, server_tcp_port)
                     self.tcp_port_out = packet[TCP].sport
-                    self.check_tcp_checksum(packet)
+                    self.assert_packet_checksums_valid(packet)
                 elif packet.haslayer(UDP):
                     self.assertEqual(packet[UDP].sport, self.udp_port_in)
                     self.assertEqual(packet[UDP].dport, server_udp_port)
@@ -2389,7 +2465,7 @@ class TestNAT44(MethodHolder):
                 if packet.haslayer(TCP):
                     self.assertEqual(packet[TCP].dport, self.tcp_port_in)
                     self.assertEqual(packet[TCP].sport, server_tcp_port)
-                    self.check_tcp_checksum(packet)
+                    self.assert_packet_checksums_valid(packet)
                 elif packet.haslayer(UDP):
                     self.assertEqual(packet[UDP].dport, self.udp_port_in)
                     self.assertEqual(packet[UDP].sport, server_udp_port)
@@ -2425,6 +2501,31 @@ class TestNAT44(MethodHolder):
         # verify number of translated packet
         self.pg1.get_capture(pkts_num)
 
+        users = self.vapi.nat44_user_dump()
+        for user in users:
+            if user.ip_address == self.pg0.remote_ip4n:
+                self.assertEqual(user.nsessions,
+                                 nat44_config.max_translations_per_user)
+                self.assertEqual(user.nstaticsessions, 0)
+
+        tcp_port = 22
+        self.nat44_add_static_mapping(self.pg0.remote_ip4, self.nat_addr,
+                                      tcp_port, tcp_port,
+                                      proto=IP_PROTOS.tcp)
+        p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
+             IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4) /
+             TCP(sport=tcp_port))
+        self.pg0.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        self.pg1.get_capture(1)
+        users = self.vapi.nat44_user_dump()
+        for user in users:
+            if user.ip_address == self.pg0.remote_ip4n:
+                self.assertEqual(user.nsessions,
+                                 nat44_config.max_translations_per_user - 1)
+                self.assertEqual(user.nstaticsessions, 1)
+
     def test_interface_addr(self):
         """ Acquire NAT44 addresses from interface """
         self.vapi.nat44_add_interface_addr(self.pg7.sw_if_index)
@@ -2605,7 +2706,8 @@ class TestNAT44(MethodHolder):
         self.pg0.add_stream(p)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        capture = self.pg1.get_capture(0)
+        self.pg1.assert_nothing_captured()
+        sleep(1)
         self.vapi.cli("ipfix flush")  # FIXME this should be an API call
         capture = self.pg3.get_capture(9)
         ipfix = IPFIXDecoder()
@@ -2626,7 +2728,7 @@ class TestNAT44(MethodHolder):
                 data = ipfix.decode_data_set(p.getlayer(Set))
                 self.verify_ipfix_addr_exhausted(data)
 
-    @unittest.skipUnless(running_extended_tests(), "part of extended tests")
+    @unittest.skipUnless(running_extended_tests, "part of extended tests")
     def test_ipfix_max_sessions(self):
         """ IPFIX logging maximum session entries exceeded """
         self.nat44_add_address(self.nat_addr)
@@ -2662,7 +2764,8 @@ class TestNAT44(MethodHolder):
         self.pg0.add_stream(p)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        self.pg1.get_capture(0)
+        self.pg1.assert_nothing_captured()
+        sleep(1)
         self.vapi.cli("ipfix flush")  # FIXME this should be an API call
         capture = self.pg3.get_capture(9)
         ipfix = IPFIXDecoder()
@@ -2683,6 +2786,32 @@ class TestNAT44(MethodHolder):
                 data = ipfix.decode_data_set(p.getlayer(Set))
                 self.verify_ipfix_max_sessions(data, max_sessions)
 
+    def test_syslog_apmap(self):
+        """ Test syslog address and port mapping creation and deletion """
+        self.vapi.syslog_set_filter(SYSLOG_SEVERITY.INFO)
+        self.vapi.syslog_set_sender(self.pg3.remote_ip4n, self.pg3.local_ip4n)
+        self.nat44_add_address(self.nat_addr)
+        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
+                                                  is_inside=0)
+
+        p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
+             IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4) /
+             TCP(sport=self.tcp_port_in, dport=20))
+        self.pg0.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg1.get_capture(1)
+        self.tcp_port_out = capture[0][TCP].sport
+        capture = self.pg3.get_capture(1)
+        self.verify_syslog_apmap(capture[0][Raw].load)
+
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        self.nat44_add_address(self.nat_addr, is_add=0)
+        capture = self.pg3.get_capture(1)
+        self.verify_syslog_apmap(capture[0][Raw].load, False)
+
     def test_pool_addr_fib(self):
         """ NAT44 add pool addresses to FIB """
         static_addr = '10.0.0.10'
@@ -2690,1142 +2819,2831 @@ class TestNAT44(MethodHolder):
         self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
         self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
                                                   is_inside=0)
-        self.nat44_add_static_mapping(self.pg0.remote_ip4, static_addr)
+        self.nat44_add_static_mapping(self.pg0.remote_ip4, static_addr)
+
+        # NAT44 address
+        p = (Ether(src=self.pg1.remote_mac, dst='ff:ff:ff:ff:ff:ff') /
+             ARP(op=ARP.who_has, pdst=self.nat_addr,
+                 psrc=self.pg1.remote_ip4, hwsrc=self.pg1.remote_mac))
+        self.pg1.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg1.get_capture(1)
+        self.assertTrue(capture[0].haslayer(ARP))
+        self.assertTrue(capture[0][ARP].op, ARP.is_at)
+
+        # 1:1 NAT address
+        p = (Ether(src=self.pg1.remote_mac, dst='ff:ff:ff:ff:ff:ff') /
+             ARP(op=ARP.who_has, pdst=static_addr,
+                 psrc=self.pg1.remote_ip4, hwsrc=self.pg1.remote_mac))
+        self.pg1.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg1.get_capture(1)
+        self.assertTrue(capture[0].haslayer(ARP))
+        self.assertTrue(capture[0][ARP].op, ARP.is_at)
+
+        # send ARP to non-NAT44 interface
+        p = (Ether(src=self.pg2.remote_mac, dst='ff:ff:ff:ff:ff:ff') /
+             ARP(op=ARP.who_has, pdst=self.nat_addr,
+                 psrc=self.pg2.remote_ip4, hwsrc=self.pg2.remote_mac))
+        self.pg2.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        self.pg1.assert_nothing_captured()
+
+        # remove addresses and verify
+        self.nat44_add_address(self.nat_addr, is_add=0)
+        self.nat44_add_static_mapping(self.pg0.remote_ip4, static_addr,
+                                      is_add=0)
+
+        p = (Ether(src=self.pg1.remote_mac, dst='ff:ff:ff:ff:ff:ff') /
+             ARP(op=ARP.who_has, pdst=self.nat_addr,
+                 psrc=self.pg1.remote_ip4, hwsrc=self.pg1.remote_mac))
+        self.pg1.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        self.pg1.assert_nothing_captured()
+
+        p = (Ether(src=self.pg1.remote_mac, dst='ff:ff:ff:ff:ff:ff') /
+             ARP(op=ARP.who_has, pdst=static_addr,
+                 psrc=self.pg1.remote_ip4, hwsrc=self.pg1.remote_mac))
+        self.pg1.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        self.pg1.assert_nothing_captured()
+
+    def test_vrf_mode(self):
+        """ NAT44 tenant VRF aware address pool mode """
+
+        vrf_id1 = 1
+        vrf_id2 = 2
+        nat_ip1 = "10.0.0.10"
+        nat_ip2 = "10.0.0.11"
+
+        self.pg0.unconfig_ip4()
+        self.pg1.unconfig_ip4()
+        self.vapi.ip_table_add_del(vrf_id1, is_add=1)
+        self.vapi.ip_table_add_del(vrf_id2, is_add=1)
+        self.pg0.set_table_ip4(vrf_id1)
+        self.pg1.set_table_ip4(vrf_id2)
+        self.pg0.config_ip4()
+        self.pg1.config_ip4()
+        self.pg0.resolve_arp()
+        self.pg1.resolve_arp()
+
+        self.nat44_add_address(nat_ip1, vrf_id=vrf_id1)
+        self.nat44_add_address(nat_ip2, vrf_id=vrf_id2)
+        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg2.sw_if_index,
+                                                  is_inside=0)
+
+        try:
+            # first VRF
+            pkts = self.create_stream_in(self.pg0, self.pg2)
+            self.pg0.add_stream(pkts)
+            self.pg_enable_capture(self.pg_interfaces)
+            self.pg_start()
+            capture = self.pg2.get_capture(len(pkts))
+            self.verify_capture_out(capture, nat_ip1)
+
+            # second VRF
+            pkts = self.create_stream_in(self.pg1, self.pg2)
+            self.pg1.add_stream(pkts)
+            self.pg_enable_capture(self.pg_interfaces)
+            self.pg_start()
+            capture = self.pg2.get_capture(len(pkts))
+            self.verify_capture_out(capture, nat_ip2)
+
+        finally:
+            self.pg0.unconfig_ip4()
+            self.pg1.unconfig_ip4()
+            self.pg0.set_table_ip4(0)
+            self.pg1.set_table_ip4(0)
+            self.pg0.config_ip4()
+            self.pg1.config_ip4()
+            self.pg0.resolve_arp()
+            self.pg1.resolve_arp()
+            self.vapi.ip_table_add_del(vrf_id1, is_add=0)
+            self.vapi.ip_table_add_del(vrf_id2, is_add=0)
+
+    def test_vrf_feature_independent(self):
+        """ NAT44 tenant VRF independent address pool mode """
+
+        nat_ip1 = "10.0.0.10"
+        nat_ip2 = "10.0.0.11"
+
+        self.nat44_add_address(nat_ip1)
+        self.nat44_add_address(nat_ip2, vrf_id=99)
+        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg2.sw_if_index,
+                                                  is_inside=0)
+
+        # first VRF
+        pkts = self.create_stream_in(self.pg0, self.pg2)
+        self.pg0.add_stream(pkts)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg2.get_capture(len(pkts))
+        self.verify_capture_out(capture, nat_ip1)
+
+        # second VRF
+        pkts = self.create_stream_in(self.pg1, self.pg2)
+        self.pg1.add_stream(pkts)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg2.get_capture(len(pkts))
+        self.verify_capture_out(capture, nat_ip1)
+
+    def test_dynamic_ipless_interfaces(self):
+        """ NAT44 interfaces without configured IP address """
+
+        self.vapi.ip_neighbor_add_del(self.pg7.sw_if_index,
+                                      mac_pton(self.pg7.remote_mac),
+                                      self.pg7.remote_ip4n,
+                                      is_static=1)
+        self.vapi.ip_neighbor_add_del(self.pg8.sw_if_index,
+                                      mac_pton(self.pg8.remote_mac),
+                                      self.pg8.remote_ip4n,
+                                      is_static=1)
+
+        self.vapi.ip_add_del_route(dst_address=self.pg7.remote_ip4n,
+                                   dst_address_length=32,
+                                   next_hop_address=self.pg7.remote_ip4n,
+                                   next_hop_sw_if_index=self.pg7.sw_if_index)
+        self.vapi.ip_add_del_route(dst_address=self.pg8.remote_ip4n,
+                                   dst_address_length=32,
+                                   next_hop_address=self.pg8.remote_ip4n,
+                                   next_hop_sw_if_index=self.pg8.sw_if_index)
+
+        self.nat44_add_address(self.nat_addr)
+        self.vapi.nat44_interface_add_del_feature(self.pg7.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg8.sw_if_index,
+                                                  is_inside=0)
+
+        # in2out
+        pkts = self.create_stream_in(self.pg7, self.pg8)
+        self.pg7.add_stream(pkts)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg8.get_capture(len(pkts))
+        self.verify_capture_out(capture)
+
+        # out2in
+        pkts = self.create_stream_out(self.pg8, self.nat_addr)
+        self.pg8.add_stream(pkts)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg7.get_capture(len(pkts))
+        self.verify_capture_in(capture, self.pg7)
+
+    def test_static_ipless_interfaces(self):
+        """ NAT44 interfaces without configured IP address - 1:1 NAT """
+
+        self.vapi.ip_neighbor_add_del(self.pg7.sw_if_index,
+                                      mac_pton(self.pg7.remote_mac),
+                                      self.pg7.remote_ip4n,
+                                      is_static=1)
+        self.vapi.ip_neighbor_add_del(self.pg8.sw_if_index,
+                                      mac_pton(self.pg8.remote_mac),
+                                      self.pg8.remote_ip4n,
+                                      is_static=1)
+
+        self.vapi.ip_add_del_route(dst_address=self.pg7.remote_ip4n,
+                                   dst_address_length=32,
+                                   next_hop_address=self.pg7.remote_ip4n,
+                                   next_hop_sw_if_index=self.pg7.sw_if_index)
+        self.vapi.ip_add_del_route(dst_address=self.pg8.remote_ip4n,
+                                   dst_address_length=32,
+                                   next_hop_address=self.pg8.remote_ip4n,
+                                   next_hop_sw_if_index=self.pg8.sw_if_index)
+
+        self.nat44_add_static_mapping(self.pg7.remote_ip4, self.nat_addr)
+        self.vapi.nat44_interface_add_del_feature(self.pg7.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg8.sw_if_index,
+                                                  is_inside=0)
+
+        # out2in
+        pkts = self.create_stream_out(self.pg8)
+        self.pg8.add_stream(pkts)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg7.get_capture(len(pkts))
+        self.verify_capture_in(capture, self.pg7)
+
+        # in2out
+        pkts = self.create_stream_in(self.pg7, self.pg8)
+        self.pg7.add_stream(pkts)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg8.get_capture(len(pkts))
+        self.verify_capture_out(capture, self.nat_addr, True)
+
+    def test_static_with_port_ipless_interfaces(self):
+        """ NAT44 interfaces without configured IP address - 1:1 NAPT """
+
+        self.tcp_port_out = 30606
+        self.udp_port_out = 30607
+        self.icmp_id_out = 30608
+
+        self.vapi.ip_neighbor_add_del(self.pg7.sw_if_index,
+                                      mac_pton(self.pg7.remote_mac),
+                                      self.pg7.remote_ip4n,
+                                      is_static=1)
+        self.vapi.ip_neighbor_add_del(self.pg8.sw_if_index,
+                                      mac_pton(self.pg8.remote_mac),
+                                      self.pg8.remote_ip4n,
+                                      is_static=1)
+
+        self.vapi.ip_add_del_route(dst_address=self.pg7.remote_ip4n,
+                                   dst_address_length=32,
+                                   next_hop_address=self.pg7.remote_ip4n,
+                                   next_hop_sw_if_index=self.pg7.sw_if_index)
+        self.vapi.ip_add_del_route(dst_address=self.pg8.remote_ip4n,
+                                   dst_address_length=32,
+                                   next_hop_address=self.pg8.remote_ip4n,
+                                   next_hop_sw_if_index=self.pg8.sw_if_index)
+
+        self.nat44_add_address(self.nat_addr)
+        self.nat44_add_static_mapping(self.pg7.remote_ip4, self.nat_addr,
+                                      self.tcp_port_in, self.tcp_port_out,
+                                      proto=IP_PROTOS.tcp)
+        self.nat44_add_static_mapping(self.pg7.remote_ip4, self.nat_addr,
+                                      self.udp_port_in, self.udp_port_out,
+                                      proto=IP_PROTOS.udp)
+        self.nat44_add_static_mapping(self.pg7.remote_ip4, self.nat_addr,
+                                      self.icmp_id_in, self.icmp_id_out,
+                                      proto=IP_PROTOS.icmp)
+        self.vapi.nat44_interface_add_del_feature(self.pg7.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg8.sw_if_index,
+                                                  is_inside=0)
+
+        # out2in
+        pkts = self.create_stream_out(self.pg8)
+        self.pg8.add_stream(pkts)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg7.get_capture(len(pkts))
+        self.verify_capture_in(capture, self.pg7)
+
+        # in2out
+        pkts = self.create_stream_in(self.pg7, self.pg8)
+        self.pg7.add_stream(pkts)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg8.get_capture(len(pkts))
+        self.verify_capture_out(capture)
+
+    def test_static_unknown_proto(self):
+        """ 1:1 NAT translate packet with unknown protocol """
+        nat_ip = "10.0.0.10"
+        self.nat44_add_static_mapping(self.pg0.remote_ip4, nat_ip)
+        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
+                                                  is_inside=0)
+
+        # in2out
+        p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
+             IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4) /
+             GRE() /
+             IP(src=self.pg2.remote_ip4, dst=self.pg3.remote_ip4) /
+             TCP(sport=1234, dport=1234))
+        self.pg0.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        p = self.pg1.get_capture(1)
+        packet = p[0]
+        try:
+            self.assertEqual(packet[IP].src, nat_ip)
+            self.assertEqual(packet[IP].dst, self.pg1.remote_ip4)
+            self.assertEqual(packet.haslayer(GRE), 1)
+            self.assert_packet_checksums_valid(packet)
+        except:
+            self.logger.error(ppp("Unexpected or invalid packet:", packet))
+            raise
+
+        # out2in
+        p = (Ether(dst=self.pg1.local_mac, src=self.pg1.remote_mac) /
+             IP(src=self.pg1.remote_ip4, dst=nat_ip) /
+             GRE() /
+             IP(src=self.pg3.remote_ip4, dst=self.pg2.remote_ip4) /
+             TCP(sport=1234, dport=1234))
+        self.pg1.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        p = self.pg0.get_capture(1)
+        packet = p[0]
+        try:
+            self.assertEqual(packet[IP].src, self.pg1.remote_ip4)
+            self.assertEqual(packet[IP].dst, self.pg0.remote_ip4)
+            self.assertEqual(packet.haslayer(GRE), 1)
+            self.assert_packet_checksums_valid(packet)
+        except:
+            self.logger.error(ppp("Unexpected or invalid packet:", packet))
+            raise
+
+    def test_hairpinning_static_unknown_proto(self):
+        """ 1:1 NAT translate packet with unknown protocol - hairpinning """
+
+        host = self.pg0.remote_hosts[0]
+        server = self.pg0.remote_hosts[1]
+
+        host_nat_ip = "10.0.0.10"
+        server_nat_ip = "10.0.0.11"
+
+        self.nat44_add_static_mapping(host.ip4, host_nat_ip)
+        self.nat44_add_static_mapping(server.ip4, server_nat_ip)
+        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
+                                                  is_inside=0)
+
+        # host to server
+        p = (Ether(dst=self.pg0.local_mac, src=host.mac) /
+             IP(src=host.ip4, dst=server_nat_ip) /
+             GRE() /
+             IP(src=self.pg2.remote_ip4, dst=self.pg3.remote_ip4) /
+             TCP(sport=1234, dport=1234))
+        self.pg0.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        p = self.pg0.get_capture(1)
+        packet = p[0]
+        try:
+            self.assertEqual(packet[IP].src, host_nat_ip)
+            self.assertEqual(packet[IP].dst, server.ip4)
+            self.assertEqual(packet.haslayer(GRE), 1)
+            self.assert_packet_checksums_valid(packet)
+        except:
+            self.logger.error(ppp("Unexpected or invalid packet:", packet))
+            raise
+
+        # server to host
+        p = (Ether(dst=self.pg0.local_mac, src=server.mac) /
+             IP(src=server.ip4, dst=host_nat_ip) /
+             GRE() /
+             IP(src=self.pg3.remote_ip4, dst=self.pg2.remote_ip4) /
+             TCP(sport=1234, dport=1234))
+        self.pg0.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        p = self.pg0.get_capture(1)
+        packet = p[0]
+        try:
+            self.assertEqual(packet[IP].src, server_nat_ip)
+            self.assertEqual(packet[IP].dst, host.ip4)
+            self.assertEqual(packet.haslayer(GRE), 1)
+            self.assert_packet_checksums_valid(packet)
+        except:
+            self.logger.error(ppp("Unexpected or invalid packet:", packet))
+            raise
+
+    def test_output_feature(self):
+        """ NAT44 interface output feature (in2out postrouting) """
+        self.nat44_add_address(self.nat_addr)
+        self.vapi.nat44_interface_add_del_output_feature(self.pg0.sw_if_index)
+        self.vapi.nat44_interface_add_del_output_feature(self.pg1.sw_if_index)
+        self.vapi.nat44_interface_add_del_output_feature(self.pg3.sw_if_index,
+                                                         is_inside=0)
+
+        # in2out
+        pkts = self.create_stream_in(self.pg0, self.pg3)
+        self.pg0.add_stream(pkts)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg3.get_capture(len(pkts))
+        self.verify_capture_out(capture)
+
+        # out2in
+        pkts = self.create_stream_out(self.pg3)
+        self.pg3.add_stream(pkts)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg0.get_capture(len(pkts))
+        self.verify_capture_in(capture, self.pg0)
+
+        # from non-NAT interface to NAT inside interface
+        pkts = self.create_stream_in(self.pg2, self.pg0)
+        self.pg2.add_stream(pkts)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg0.get_capture(len(pkts))
+        self.verify_capture_no_translation(capture, self.pg2, self.pg0)
+
+    def test_output_feature_vrf_aware(self):
+        """ NAT44 interface output feature VRF aware (in2out postrouting) """
+        nat_ip_vrf10 = "10.0.0.10"
+        nat_ip_vrf20 = "10.0.0.20"
+
+        self.vapi.ip_add_del_route(dst_address=self.pg3.remote_ip4n,
+                                   dst_address_length=32,
+                                   next_hop_address=self.pg3.remote_ip4n,
+                                   next_hop_sw_if_index=self.pg3.sw_if_index,
+                                   table_id=10)
+        self.vapi.ip_add_del_route(dst_address=self.pg3.remote_ip4n,
+                                   dst_address_length=32,
+                                   next_hop_address=self.pg3.remote_ip4n,
+                                   next_hop_sw_if_index=self.pg3.sw_if_index,
+                                   table_id=20)
+
+        self.nat44_add_address(nat_ip_vrf10, vrf_id=10)
+        self.nat44_add_address(nat_ip_vrf20, vrf_id=20)
+        self.vapi.nat44_interface_add_del_output_feature(self.pg4.sw_if_index)
+        self.vapi.nat44_interface_add_del_output_feature(self.pg6.sw_if_index)
+        self.vapi.nat44_interface_add_del_output_feature(self.pg3.sw_if_index,
+                                                         is_inside=0)
+
+        # in2out VRF 10
+        pkts = self.create_stream_in(self.pg4, self.pg3)
+        self.pg4.add_stream(pkts)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg3.get_capture(len(pkts))
+        self.verify_capture_out(capture, nat_ip=nat_ip_vrf10)
+
+        # out2in VRF 10
+        pkts = self.create_stream_out(self.pg3, dst_ip=nat_ip_vrf10)
+        self.pg3.add_stream(pkts)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg4.get_capture(len(pkts))
+        self.verify_capture_in(capture, self.pg4)
+
+        # in2out VRF 20
+        pkts = self.create_stream_in(self.pg6, self.pg3)
+        self.pg6.add_stream(pkts)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg3.get_capture(len(pkts))
+        self.verify_capture_out(capture, nat_ip=nat_ip_vrf20)
+
+        # out2in VRF 20
+        pkts = self.create_stream_out(self.pg3, dst_ip=nat_ip_vrf20)
+        self.pg3.add_stream(pkts)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg6.get_capture(len(pkts))
+        self.verify_capture_in(capture, self.pg6)
+
+    def test_output_feature_hairpinning(self):
+        """ NAT44 interface output feature hairpinning (in2out postrouting) """
+        host = self.pg0.remote_hosts[0]
+        server = self.pg0.remote_hosts[1]
+        host_in_port = 1234
+        host_out_port = 0
+        server_in_port = 5678
+        server_out_port = 8765
+
+        self.nat44_add_address(self.nat_addr)
+        self.vapi.nat44_interface_add_del_output_feature(self.pg0.sw_if_index)
+        self.vapi.nat44_interface_add_del_output_feature(self.pg1.sw_if_index,
+                                                         is_inside=0)
+
+        # add static mapping for server
+        self.nat44_add_static_mapping(server.ip4, self.nat_addr,
+                                      server_in_port, server_out_port,
+                                      proto=IP_PROTOS.tcp)
+
+        # send packet from host to server
+        p = (Ether(src=host.mac, dst=self.pg0.local_mac) /
+             IP(src=host.ip4, dst=self.nat_addr) /
+             TCP(sport=host_in_port, dport=server_out_port))
+        self.pg0.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg0.get_capture(1)
+        p = capture[0]
+        try:
+            ip = p[IP]
+            tcp = p[TCP]
+            self.assertEqual(ip.src, self.nat_addr)
+            self.assertEqual(ip.dst, server.ip4)
+            self.assertNotEqual(tcp.sport, host_in_port)
+            self.assertEqual(tcp.dport, server_in_port)
+            self.assert_packet_checksums_valid(p)
+            host_out_port = tcp.sport
+        except:
+            self.logger.error(ppp("Unexpected or invalid packet:", p))
+            raise
+
+        # send reply from server to host
+        p = (Ether(src=server.mac, dst=self.pg0.local_mac) /
+             IP(src=server.ip4, dst=self.nat_addr) /
+             TCP(sport=server_in_port, dport=host_out_port))
+        self.pg0.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg0.get_capture(1)
+        p = capture[0]
+        try:
+            ip = p[IP]
+            tcp = p[TCP]
+            self.assertEqual(ip.src, self.nat_addr)
+            self.assertEqual(ip.dst, host.ip4)
+            self.assertEqual(tcp.sport, server_out_port)
+            self.assertEqual(tcp.dport, host_in_port)
+            self.assert_packet_checksums_valid(p)
+        except:
+            self.logger.error(ppp("Unexpected or invalid packet:", p))
+            raise
+
+    def test_one_armed_nat44(self):
+        """ One armed NAT44 """
+        remote_host = self.pg9.remote_hosts[0]
+        local_host = self.pg9.remote_hosts[1]
+        external_port = 0
+
+        self.nat44_add_address(self.nat_addr)
+        self.vapi.nat44_interface_add_del_feature(self.pg9.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg9.sw_if_index,
+                                                  is_inside=0)
+
+        # in2out
+        p = (Ether(src=self.pg9.remote_mac, dst=self.pg9.local_mac) /
+             IP(src=local_host.ip4, dst=remote_host.ip4) /
+             TCP(sport=12345, dport=80))
+        self.pg9.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg9.get_capture(1)
+        p = capture[0]
+        try:
+            ip = p[IP]
+            tcp = p[TCP]
+            self.assertEqual(ip.src, self.nat_addr)
+            self.assertEqual(ip.dst, remote_host.ip4)
+            self.assertNotEqual(tcp.sport, 12345)
+            external_port = tcp.sport
+            self.assertEqual(tcp.dport, 80)
+            self.assert_packet_checksums_valid(p)
+        except:
+            self.logger.error(ppp("Unexpected or invalid packet:", p))
+            raise
+
+        # out2in
+        p = (Ether(src=self.pg9.remote_mac, dst=self.pg9.local_mac) /
+             IP(src=remote_host.ip4, dst=self.nat_addr) /
+             TCP(sport=80, dport=external_port))
+        self.pg9.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg9.get_capture(1)
+        p = capture[0]
+        try:
+            ip = p[IP]
+            tcp = p[TCP]
+            self.assertEqual(ip.src, remote_host.ip4)
+            self.assertEqual(ip.dst, local_host.ip4)
+            self.assertEqual(tcp.sport, 80)
+            self.assertEqual(tcp.dport, 12345)
+            self.assert_packet_checksums_valid(p)
+        except:
+            self.logger.error(ppp("Unexpected or invalid packet:", p))
+            raise
+
+        err = self.statistics.get_counter('/err/nat44-classify/next in2out')
+        self.assertEqual(err, 1)
+        err = self.statistics.get_counter('/err/nat44-classify/next out2in')
+        self.assertEqual(err, 1)
+
+    def test_del_session(self):
+        """ Delete NAT44 session """
+        self.nat44_add_address(self.nat_addr)
+        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
+                                                  is_inside=0)
+
+        pkts = self.create_stream_in(self.pg0, self.pg1)
+        self.pg0.add_stream(pkts)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        self.pg1.get_capture(len(pkts))
+
+        sessions = self.vapi.nat44_user_session_dump(self.pg0.remote_ip4n, 0)
+        nsessions = len(sessions)
+
+        self.vapi.nat44_del_session(sessions[0].inside_ip_address,
+                                    sessions[0].inside_port,
+                                    sessions[0].protocol)
+        self.vapi.nat44_del_session(sessions[1].outside_ip_address,
+                                    sessions[1].outside_port,
+                                    sessions[1].protocol,
+                                    is_in=0)
+
+        sessions = self.vapi.nat44_user_session_dump(self.pg0.remote_ip4n, 0)
+        self.assertEqual(nsessions - len(sessions), 2)
+
+        self.vapi.nat44_del_session(sessions[0].inside_ip_address,
+                                    sessions[0].inside_port,
+                                    sessions[0].protocol)
+
+        self.verify_no_nat44_user()
+
+    def test_set_get_reass(self):
+        """ NAT44 set/get virtual fragmentation reassembly """
+        reas_cfg1 = self.vapi.nat_get_reass()
+
+        self.vapi.nat_set_reass(timeout=reas_cfg1.ip4_timeout + 5,
+                                max_reass=reas_cfg1.ip4_max_reass * 2,
+                                max_frag=reas_cfg1.ip4_max_frag * 2)
+
+        reas_cfg2 = self.vapi.nat_get_reass()
+
+        self.assertEqual(reas_cfg1.ip4_timeout + 5, reas_cfg2.ip4_timeout)
+        self.assertEqual(reas_cfg1.ip4_max_reass * 2, reas_cfg2.ip4_max_reass)
+        self.assertEqual(reas_cfg1.ip4_max_frag * 2, reas_cfg2.ip4_max_frag)
+
+        self.vapi.nat_set_reass(drop_frag=1)
+        self.assertTrue(self.vapi.nat_get_reass().ip4_drop_frag)
+
+    def test_frag_in_order(self):
+        """ NAT44 translate fragments arriving in order """
+
+        self.nat44_add_address(self.nat_addr)
+        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
+                                                  is_inside=0)
+
+        self.frag_in_order(proto=IP_PROTOS.tcp)
+        self.frag_in_order(proto=IP_PROTOS.udp)
+        self.frag_in_order(proto=IP_PROTOS.icmp)
+
+    def test_frag_forwarding(self):
+        """ NAT44 forwarding fragment test """
+        self.vapi.nat44_add_interface_addr(self.pg1.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
+                                                  is_inside=0)
+        self.vapi.nat44_forwarding_enable_disable(1)
+
+        data = "A" * 16 + "B" * 16 + "C" * 3
+        pkts = self.create_stream_frag(self.pg1,
+                                       self.pg0.remote_ip4,
+                                       4789,
+                                       4789,
+                                       data,
+                                       proto=IP_PROTOS.udp)
+        self.pg1.add_stream(pkts)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        frags = self.pg0.get_capture(len(pkts))
+        p = self.reass_frags_and_verify(frags,
+                                        self.pg1.remote_ip4,
+                                        self.pg0.remote_ip4)
+        self.assertEqual(p[UDP].sport, 4789)
+        self.assertEqual(p[UDP].dport, 4789)
+        self.assertEqual(data, p[Raw].load)
+
+    def test_reass_hairpinning(self):
+        """ NAT44 fragments hairpinning """
+
+        self.server = self.pg0.remote_hosts[1]
+        self.host_in_port = random.randint(1025, 65535)
+        self.server_in_port = random.randint(1025, 65535)
+        self.server_out_port = random.randint(1025, 65535)
+
+        self.nat44_add_address(self.nat_addr)
+        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
+                                                  is_inside=0)
+        # add static mapping for server
+        self.nat44_add_static_mapping(self.server.ip4, self.nat_addr,
+                                      self.server_in_port,
+                                      self.server_out_port,
+                                      proto=IP_PROTOS.tcp)
+        self.nat44_add_static_mapping(self.server.ip4, self.nat_addr,
+                                      self.server_in_port,
+                                      self.server_out_port,
+                                      proto=IP_PROTOS.udp)
+        self.nat44_add_static_mapping(self.server.ip4, self.nat_addr)
+
+        self.reass_hairpinning(proto=IP_PROTOS.tcp)
+        self.reass_hairpinning(proto=IP_PROTOS.udp)
+        self.reass_hairpinning(proto=IP_PROTOS.icmp)
+
+    def test_frag_out_of_order(self):
+        """ NAT44 translate fragments arriving out of order """
+
+        self.nat44_add_address(self.nat_addr)
+        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
+                                                  is_inside=0)
+
+        self.frag_out_of_order(proto=IP_PROTOS.tcp)
+        self.frag_out_of_order(proto=IP_PROTOS.udp)
+        self.frag_out_of_order(proto=IP_PROTOS.icmp)
+
+    def test_port_restricted(self):
+        """ Port restricted NAT44 (MAP-E CE) """
+        self.nat44_add_address(self.nat_addr)
+        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
+                                                  is_inside=0)
+        self.vapi.nat_set_addr_and_port_alloc_alg(alg=1,
+                                                  psid_offset=6,
+                                                  psid_length=6,
+                                                  psid=10)
+
+        p = (Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac) /
+             IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4) /
+             TCP(sport=4567, dport=22))
+        self.pg0.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg1.get_capture(1)
+        p = capture[0]
+        try:
+            ip = p[IP]
+            tcp = p[TCP]
+            self.assertEqual(ip.dst, self.pg1.remote_ip4)
+            self.assertEqual(ip.src, self.nat_addr)
+            self.assertEqual(tcp.dport, 22)
+            self.assertNotEqual(tcp.sport, 4567)
+            self.assertEqual((tcp.sport >> 6) & 63, 10)
+            self.assert_packet_checksums_valid(p)
+        except:
+            self.logger.error(ppp("Unexpected or invalid packet:", p))
+            raise
+
+    def test_port_range(self):
+        """ External address port range """
+        self.nat44_add_address(self.nat_addr)
+        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
+                                                  is_inside=0)
+        self.vapi.nat_set_addr_and_port_alloc_alg(alg=2,
+                                                  start_port=1025,
+                                                  end_port=1027)
+
+        pkts = []
+        for port in range(0, 5):
+            p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
+                 IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4) /
+                 TCP(sport=1125 + port))
+            pkts.append(p)
+        self.pg0.add_stream(pkts)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg1.get_capture(3)
+        for p in capture:
+            tcp = p[TCP]
+            self.assertGreaterEqual(tcp.sport, 1025)
+            self.assertLessEqual(tcp.sport, 1027)
+
+    def test_ipfix_max_frags(self):
+        """ IPFIX logging maximum fragments pending reassembly exceeded """
+        self.nat44_add_address(self.nat_addr)
+        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
+                                                  is_inside=0)
+        self.vapi.nat_set_reass(max_frag=1)
+        self.vapi.set_ipfix_exporter(collector_address=self.pg3.remote_ip4n,
+                                     src_address=self.pg3.local_ip4n,
+                                     path_mtu=512,
+                                     template_interval=10)
+        self.vapi.nat_ipfix(domain_id=self.ipfix_domain_id,
+                            src_port=self.ipfix_src_port)
+
+        data = "A" * 4 + "B" * 16 + "C" * 3
+        self.tcp_port_in = random.randint(1025, 65535)
+        pkts = self.create_stream_frag(self.pg0,
+                                       self.pg1.remote_ip4,
+                                       self.tcp_port_in,
+                                       20,
+                                       data)
+        pkts.reverse()
+        self.pg0.add_stream(pkts)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        self.pg1.assert_nothing_captured()
+        sleep(1)
+        self.vapi.cli("ipfix flush")  # FIXME this should be an API call
+        capture = self.pg3.get_capture(9)
+        ipfix = IPFIXDecoder()
+        # first load template
+        for p in capture:
+            self.assertTrue(p.haslayer(IPFIX))
+            self.assertEqual(p[IP].src, self.pg3.local_ip4)
+            self.assertEqual(p[IP].dst, self.pg3.remote_ip4)
+            self.assertEqual(p[UDP].sport, self.ipfix_src_port)
+            self.assertEqual(p[UDP].dport, 4739)
+            self.assertEqual(p[IPFIX].observationDomainID,
+                             self.ipfix_domain_id)
+            if p.haslayer(Template):
+                ipfix.add_template(p.getlayer(Template))
+        # verify events in data set
+        for p in capture:
+            if p.haslayer(Data):
+                data = ipfix.decode_data_set(p.getlayer(Set))
+                self.verify_ipfix_max_fragments_ip4(data, 1,
+                                                    self.pg0.remote_ip4n)
+
+    def test_multiple_outside_vrf(self):
+        """ Multiple outside VRF """
+        vrf_id1 = 1
+        vrf_id2 = 2
+
+        self.pg1.unconfig_ip4()
+        self.pg2.unconfig_ip4()
+        self.vapi.ip_table_add_del(vrf_id1, is_add=1)
+        self.vapi.ip_table_add_del(vrf_id2, is_add=1)
+        self.pg1.set_table_ip4(vrf_id1)
+        self.pg2.set_table_ip4(vrf_id2)
+        self.pg1.config_ip4()
+        self.pg2.config_ip4()
+        self.pg1.resolve_arp()
+        self.pg2.resolve_arp()
+
+        self.nat44_add_address(self.nat_addr)
+        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
+                                                  is_inside=0)
+        self.vapi.nat44_interface_add_del_feature(self.pg2.sw_if_index,
+                                                  is_inside=0)
+
+        try:
+            # first VRF
+            pkts = self.create_stream_in(self.pg0, self.pg1)
+            self.pg0.add_stream(pkts)
+            self.pg_enable_capture(self.pg_interfaces)
+            self.pg_start()
+            capture = self.pg1.get_capture(len(pkts))
+            self.verify_capture_out(capture, self.nat_addr)
+
+            pkts = self.create_stream_out(self.pg1, self.nat_addr)
+            self.pg1.add_stream(pkts)
+            self.pg_enable_capture(self.pg_interfaces)
+            self.pg_start()
+            capture = self.pg0.get_capture(len(pkts))
+            self.verify_capture_in(capture, self.pg0)
+
+            self.tcp_port_in = 60303
+            self.udp_port_in = 60304
+            self.icmp_id_in = 60305
+
+            # second VRF
+            pkts = self.create_stream_in(self.pg0, self.pg2)
+            self.pg0.add_stream(pkts)
+            self.pg_enable_capture(self.pg_interfaces)
+            self.pg_start()
+            capture = self.pg2.get_capture(len(pkts))
+            self.verify_capture_out(capture, self.nat_addr)
+
+            pkts = self.create_stream_out(self.pg2, self.nat_addr)
+            self.pg2.add_stream(pkts)
+            self.pg_enable_capture(self.pg_interfaces)
+            self.pg_start()
+            capture = self.pg0.get_capture(len(pkts))
+            self.verify_capture_in(capture, self.pg0)
+
+        finally:
+            self.pg1.unconfig_ip4()
+            self.pg2.unconfig_ip4()
+            self.pg1.set_table_ip4(0)
+            self.pg2.set_table_ip4(0)
+            self.pg1.config_ip4()
+            self.pg2.config_ip4()
+            self.pg1.resolve_arp()
+            self.pg2.resolve_arp()
+
+    @unittest.skipUnless(running_extended_tests, "part of extended tests")
+    def test_session_timeout(self):
+        """ NAT44 session timeouts """
+        self.nat44_add_address(self.nat_addr)
+        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
+                                                  is_inside=0)
+        self.vapi.nat_set_timeouts(udp=5)
+
+        max_sessions = 1000
+        pkts = []
+        for i in range(0, max_sessions):
+            src = "10.10.%u.%u" % ((i & 0xFF00) >> 8, i & 0xFF)
+            p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
+                 IP(src=src, dst=self.pg1.remote_ip4) /
+                 UDP(sport=1025, dport=53))
+            pkts.append(p)
+        self.pg0.add_stream(pkts)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        self.pg1.get_capture(max_sessions)
+
+        sleep(6)
+
+        pkts = []
+        for i in range(0, max_sessions):
+            src = "10.10.%u.%u" % ((i & 0xFF00) >> 8, i & 0xFF)
+            p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
+                 IP(src=src, dst=self.pg1.remote_ip4) /
+                 UDP(sport=1026, dport=53))
+            pkts.append(p)
+        self.pg0.add_stream(pkts)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        self.pg1.get_capture(max_sessions)
+
+        nsessions = 0
+        users = self.vapi.nat44_user_dump()
+        for user in users:
+            nsessions = nsessions + user.nsessions
+        self.assertLess(nsessions, 2 * max_sessions)
+
+    def test_mss_clamping(self):
+        """ TCP MSS clamping """
+        self.nat44_add_address(self.nat_addr)
+        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
+                                                  is_inside=0)
+
+        p = (Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac) /
+             IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4) /
+             TCP(sport=self.tcp_port_in, dport=self.tcp_external_port,
+                 flags="S", options=[('MSS', 1400)]))
+
+        self.vapi.nat_set_mss_clamping(enable=1, mss_value=1000)
+        self.pg0.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg1.get_capture(1)
+        # Negotiated MSS value greater than configured - changed
+        self.verify_mss_value(capture[0], 1000)
+
+        self.vapi.nat_set_mss_clamping(enable=0)
+        self.pg0.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg1.get_capture(1)
+        # MSS clamping disabled - negotiated MSS unchanged
+        self.verify_mss_value(capture[0], 1400)
+
+        self.vapi.nat_set_mss_clamping(enable=1, mss_value=1500)
+        self.pg0.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg1.get_capture(1)
+        # Negotiated MSS value smaller than configured - unchanged
+        self.verify_mss_value(capture[0], 1400)
+
+    def tearDown(self):
+        super(TestNAT44, self).tearDown()
+        if not self.vpp_dead:
+            self.logger.info(self.vapi.cli("show nat44 addresses"))
+            self.logger.info(self.vapi.cli("show nat44 interfaces"))
+            self.logger.info(self.vapi.cli("show nat44 static mappings"))
+            self.logger.info(self.vapi.cli("show nat44 interface address"))
+            self.logger.info(self.vapi.cli("show nat44 sessions detail"))
+            self.logger.info(self.vapi.cli("show nat virtual-reassembly"))
+            self.logger.info(self.vapi.cli("show nat44 hash tables detail"))
+            self.logger.info(self.vapi.cli("show nat timeouts"))
+            self.logger.info(
+                self.vapi.cli("show nat addr-port-assignment-alg"))
+            self.clear_nat44()
+            self.vapi.cli("clear logging")
+
+
+class TestNAT44EndpointDependent(MethodHolder):
+    """ Endpoint-Dependent mapping and filtering test cases """
+
+    @classmethod
+    def setUpConstants(cls):
+        super(TestNAT44EndpointDependent, cls).setUpConstants()
+        cls.vpp_cmdline.extend(["nat", "{", "endpoint-dependent", "}"])
+
+    @classmethod
+    def setUpClass(cls):
+        super(TestNAT44EndpointDependent, cls).setUpClass()
+        cls.vapi.cli("set log class nat level debug")
+        try:
+            cls.tcp_port_in = 6303
+            cls.tcp_port_out = 6303
+            cls.udp_port_in = 6304
+            cls.udp_port_out = 6304
+            cls.icmp_id_in = 6305
+            cls.icmp_id_out = 6305
+            cls.nat_addr = '10.0.0.3'
+            cls.nat_addr_n = socket.inet_pton(socket.AF_INET, cls.nat_addr)
+            cls.ipfix_src_port = 4739
+            cls.ipfix_domain_id = 1
+            cls.tcp_external_port = 80
+
+            cls.create_pg_interfaces(range(7))
+            cls.interfaces = list(cls.pg_interfaces[0:3])
+
+            for i in cls.interfaces:
+                i.admin_up()
+                i.config_ip4()
+                i.resolve_arp()
+
+            cls.pg0.generate_remote_hosts(3)
+            cls.pg0.configure_ipv4_neighbors()
+
+            cls.pg3.admin_up()
+
+            cls.pg4.generate_remote_hosts(2)
+            cls.pg4.config_ip4()
+            ip_addr_n = socket.inet_pton(socket.AF_INET, "10.0.0.1")
+            cls.vapi.sw_interface_add_del_address(cls.pg4.sw_if_index,
+                                                  ip_addr_n,
+                                                  24)
+            cls.pg4.admin_up()
+            cls.pg4.resolve_arp()
+            cls.pg4._remote_hosts[1]._ip4 = cls.pg4._remote_hosts[0]._ip4
+            cls.pg4.resolve_arp()
+
+            zero_ip4n = socket.inet_pton(socket.AF_INET, "0.0.0.0")
+            cls.vapi.ip_table_add_del(1, is_add=1)
+
+            cls.pg5._local_ip4 = "10.1.1.1"
+            cls.pg5._local_ip4n = socket.inet_pton(socket.AF_INET,
+                                                   cls.pg5.local_ip4)
+            cls.pg5._remote_hosts[0]._ip4 = "10.1.1.2"
+            cls.pg5._remote_hosts[0]._ip4n = socket.inet_pton(
+                socket.AF_INET, cls.pg5.remote_ip4)
+            cls.pg5.set_table_ip4(1)
+            cls.pg5.config_ip4()
+            cls.pg5.admin_up()
+            cls.vapi.ip_add_del_route(dst_address=cls.pg5.remote_ip4n,
+                                      dst_address_length=32,
+                                      table_id=1,
+                                      next_hop_sw_if_index=cls.pg5.sw_if_index,
+                                      next_hop_address=zero_ip4n)
+
+            cls.pg6._local_ip4 = "10.1.2.1"
+            cls.pg6._local_ip4n = socket.inet_pton(socket.AF_INET,
+                                                   cls.pg6.local_ip4)
+            cls.pg6._remote_hosts[0]._ip4 = "10.1.2.2"
+            cls.pg6._remote_hosts[0]._ip4n = socket.inet_pton(
+                socket.AF_INET, cls.pg6.remote_ip4)
+            cls.pg6.set_table_ip4(1)
+            cls.pg6.config_ip4()
+            cls.pg6.admin_up()
+            cls.vapi.ip_add_del_route(dst_address=cls.pg6.remote_ip4n,
+                                      dst_address_length=32,
+                                      table_id=1,
+                                      next_hop_sw_if_index=cls.pg6.sw_if_index,
+                                      next_hop_address=zero_ip4n)
+
+            cls.vapi.ip_add_del_route(dst_address=cls.pg6.remote_ip4n,
+                                      dst_address_length=16,
+                                      next_hop_address=zero_ip4n,
+                                      table_id=0,
+                                      next_hop_table_id=1)
+            cls.vapi.ip_add_del_route(dst_address=zero_ip4n,
+                                      dst_address_length=0,
+                                      next_hop_address=zero_ip4n,
+                                      table_id=1,
+                                      next_hop_table_id=0)
+            cls.vapi.ip_add_del_route(dst_address=zero_ip4n,
+                                      dst_address_length=0,
+                                      table_id=0,
+                                      next_hop_sw_if_index=cls.pg1.sw_if_index,
+                                      next_hop_address=cls.pg1.local_ip4n)
+
+            cls.pg5.resolve_arp()
+            cls.pg6.resolve_arp()
+
+        except Exception:
+            super(TestNAT44EndpointDependent, cls).tearDownClass()
+            raise
+
+    def test_frag_in_order(self):
+        """ NAT44 translate fragments arriving in order """
+        self.nat44_add_address(self.nat_addr)
+        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
+                                                  is_inside=0)
+        self.frag_in_order(proto=IP_PROTOS.tcp)
+        self.frag_in_order(proto=IP_PROTOS.udp)
+        self.frag_in_order(proto=IP_PROTOS.icmp)
+
+    def test_frag_in_order_dont_translate(self):
+        """ NAT44 don't translate fragments arriving in order """
+        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
+                                                  is_inside=0)
+        self.vapi.nat44_forwarding_enable_disable(enable=True)
+        self.frag_in_order(proto=IP_PROTOS.tcp, dont_translate=True)
+
+    def test_frag_out_of_order(self):
+        """ NAT44 translate fragments arriving out of order """
+        self.nat44_add_address(self.nat_addr)
+        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
+                                                  is_inside=0)
+        self.frag_out_of_order(proto=IP_PROTOS.tcp)
+        self.frag_out_of_order(proto=IP_PROTOS.udp)
+        self.frag_out_of_order(proto=IP_PROTOS.icmp)
+
+    def test_frag_out_of_order_dont_translate(self):
+        """ NAT44 don't translate fragments arriving out of order """
+        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
+                                                  is_inside=0)
+        self.vapi.nat44_forwarding_enable_disable(enable=True)
+        self.frag_out_of_order(proto=IP_PROTOS.tcp, dont_translate=True)
+
+    def test_frag_in_order_in_plus_out(self):
+        """ in+out interface fragments in order """
+        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index,
+                                                  is_inside=0)
+        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
+                                                  is_inside=0)
+
+        self.server = self.pg1.remote_hosts[0]
+
+        self.server_in_addr = self.server.ip4
+        self.server_out_addr = '11.11.11.11'
+        self.server_in_port = random.randint(1025, 65535)
+        self.server_out_port = random.randint(1025, 65535)
+
+        self.nat44_add_address(self.server_out_addr)
+
+        # add static mappings for server
+        self.nat44_add_static_mapping(self.server_in_addr,
+                                      self.server_out_addr,
+                                      self.server_in_port,
+                                      self.server_out_port,
+                                      proto=IP_PROTOS.tcp)
+        self.nat44_add_static_mapping(self.server_in_addr,
+                                      self.server_out_addr,
+                                      self.server_in_port,
+                                      self.server_out_port,
+                                      proto=IP_PROTOS.udp)
+        self.nat44_add_static_mapping(self.server_in_addr,
+                                      self.server_out_addr,
+                                      proto=IP_PROTOS.icmp)
+
+        self.vapi.nat_set_reass(timeout=10)
+
+        self.frag_in_order_in_plus_out(proto=IP_PROTOS.tcp)
+        self.frag_in_order_in_plus_out(proto=IP_PROTOS.udp)
+        self.frag_in_order_in_plus_out(proto=IP_PROTOS.icmp)
+
+    def test_frag_out_of_order_in_plus_out(self):
+        """ in+out interface fragments out of order """
+        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index,
+                                                  is_inside=0)
+        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
+                                                  is_inside=0)
+
+        self.server = self.pg1.remote_hosts[0]
+
+        self.server_in_addr = self.server.ip4
+        self.server_out_addr = '11.11.11.11'
+        self.server_in_port = random.randint(1025, 65535)
+        self.server_out_port = random.randint(1025, 65535)
+
+        self.nat44_add_address(self.server_out_addr)
+
+        # add static mappings for server
+        self.nat44_add_static_mapping(self.server_in_addr,
+                                      self.server_out_addr,
+                                      self.server_in_port,
+                                      self.server_out_port,
+                                      proto=IP_PROTOS.tcp)
+        self.nat44_add_static_mapping(self.server_in_addr,
+                                      self.server_out_addr,
+                                      self.server_in_port,
+                                      self.server_out_port,
+                                      proto=IP_PROTOS.udp)
+        self.nat44_add_static_mapping(self.server_in_addr,
+                                      self.server_out_addr,
+                                      proto=IP_PROTOS.icmp)
+
+        self.vapi.nat_set_reass(timeout=10)
+
+        self.frag_out_of_order_in_plus_out(proto=IP_PROTOS.tcp)
+        self.frag_out_of_order_in_plus_out(proto=IP_PROTOS.udp)
+        self.frag_out_of_order_in_plus_out(proto=IP_PROTOS.icmp)
+
+    def test_reass_hairpinning(self):
+        """ NAT44 fragments hairpinning """
+        self.server = self.pg0.remote_hosts[1]
+        self.host_in_port = random.randint(1025, 65535)
+        self.server_in_port = random.randint(1025, 65535)
+        self.server_out_port = random.randint(1025, 65535)
+
+        self.nat44_add_address(self.nat_addr)
+        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
+                                                  is_inside=0)
+        # add static mapping for server
+        self.nat44_add_static_mapping(self.server.ip4, self.nat_addr,
+                                      self.server_in_port,
+                                      self.server_out_port,
+                                      proto=IP_PROTOS.tcp)
+        self.nat44_add_static_mapping(self.server.ip4, self.nat_addr,
+                                      self.server_in_port,
+                                      self.server_out_port,
+                                      proto=IP_PROTOS.udp)
+        self.nat44_add_static_mapping(self.server.ip4, self.nat_addr)
+
+        self.reass_hairpinning(proto=IP_PROTOS.tcp)
+        self.reass_hairpinning(proto=IP_PROTOS.udp)
+        self.reass_hairpinning(proto=IP_PROTOS.icmp)
+
+    def test_dynamic(self):
+        """ NAT44 dynamic translation test """
+
+        self.nat44_add_address(self.nat_addr)
+        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
+                                                  is_inside=0)
+
+        nat_config = self.vapi.nat_show_config()
+        self.assertEqual(1, nat_config.endpoint_dependent)
+
+        # in2out
+        tcpn = self.statistics.get_counter(
+            '/err/nat44-ed-in2out-slowpath/TCP packets')
+        udpn = self.statistics.get_counter(
+            '/err/nat44-ed-in2out-slowpath/UDP packets')
+        icmpn = self.statistics.get_counter(
+            '/err/nat44-ed-in2out-slowpath/ICMP packets')
+        totaln = self.statistics.get_counter(
+            '/err/nat44-ed-in2out-slowpath/good in2out packets processed')
+
+        pkts = self.create_stream_in(self.pg0, self.pg1)
+        self.pg0.add_stream(pkts)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg1.get_capture(len(pkts))
+        self.verify_capture_out(capture)
+
+        err = self.statistics.get_counter(
+            '/err/nat44-ed-in2out-slowpath/TCP packets')
+        self.assertEqual(err - tcpn, 1)
+        err = self.statistics.get_counter(
+            '/err/nat44-ed-in2out-slowpath/UDP packets')
+        self.assertEqual(err - udpn, 1)
+        err = self.statistics.get_counter(
+            '/err/nat44-ed-in2out-slowpath/ICMP packets')
+        self.assertEqual(err - icmpn, 1)
+        err = self.statistics.get_counter(
+            '/err/nat44-ed-in2out-slowpath/good in2out packets processed')
+        self.assertEqual(err - totaln, 3)
+
+        # out2in
+        tcpn = self.statistics.get_counter('/err/nat44-ed-out2in/TCP packets')
+        udpn = self.statistics.get_counter('/err/nat44-ed-out2in/UDP packets')
+        icmpn = self.statistics.get_counter(
+            '/err/nat44-ed-out2in-slowpath/ICMP packets')
+        totaln = self.statistics.get_counter(
+            '/err/nat44-ed-out2in/good out2in packets processed')
+
+        pkts = self.create_stream_out(self.pg1)
+        self.pg1.add_stream(pkts)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg0.get_capture(len(pkts))
+        self.verify_capture_in(capture, self.pg0)
+
+        err = self.statistics.get_counter('/err/nat44-ed-out2in/TCP packets')
+        self.assertEqual(err - tcpn, 1)
+        err = self.statistics.get_counter('/err/nat44-ed-out2in/UDP packets')
+        self.assertEqual(err - udpn, 1)
+        err = self.statistics.get_counter(
+            '/err/nat44-ed-out2in-slowpath/ICMP packets')
+        self.assertEqual(err - icmpn, 1)
+        err = self.statistics.get_counter(
+            '/err/nat44-ed-out2in/good out2in packets processed')
+        self.assertEqual(err - totaln, 2)
+
+        users = self.statistics.get_counter('/nat44/total-users')
+        self.assertEqual(users[0][0], 1)
+        sessions = self.statistics.get_counter('/nat44/total-sessions')
+        self.assertEqual(sessions[0][0], 3)
+
+    def test_forwarding(self):
+        """ NAT44 forwarding test """
+
+        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
+                                                  is_inside=0)
+        self.vapi.nat44_forwarding_enable_disable(1)
+
+        real_ip = self.pg0.remote_ip4n
+        alias_ip = self.nat_addr_n
+        self.vapi.nat44_add_del_static_mapping(local_ip=real_ip,
+                                               external_ip=alias_ip)
+
+        try:
+            # in2out - static mapping match
+
+            pkts = self.create_stream_out(self.pg1)
+            self.pg1.add_stream(pkts)
+            self.pg_enable_capture(self.pg_interfaces)
+            self.pg_start()
+            capture = self.pg0.get_capture(len(pkts))
+            self.verify_capture_in(capture, self.pg0)
+
+            pkts = self.create_stream_in(self.pg0, self.pg1)
+            self.pg0.add_stream(pkts)
+            self.pg_enable_capture(self.pg_interfaces)
+            self.pg_start()
+            capture = self.pg1.get_capture(len(pkts))
+            self.verify_capture_out(capture, same_port=True)
+
+            # in2out - no static mapping match
+
+            host0 = self.pg0.remote_hosts[0]
+            self.pg0.remote_hosts[0] = self.pg0.remote_hosts[1]
+            try:
+                pkts = self.create_stream_out(self.pg1,
+                                              dst_ip=self.pg0.remote_ip4,
+                                              use_inside_ports=True)
+                self.pg1.add_stream(pkts)
+                self.pg_enable_capture(self.pg_interfaces)
+                self.pg_start()
+                capture = self.pg0.get_capture(len(pkts))
+                self.verify_capture_in(capture, self.pg0)
+
+                pkts = self.create_stream_in(self.pg0, self.pg1)
+                self.pg0.add_stream(pkts)
+                self.pg_enable_capture(self.pg_interfaces)
+                self.pg_start()
+                capture = self.pg1.get_capture(len(pkts))
+                self.verify_capture_out(capture, nat_ip=self.pg0.remote_ip4,
+                                        same_port=True)
+            finally:
+                self.pg0.remote_hosts[0] = host0
+
+            user = self.pg0.remote_hosts[1]
+            sessions = self.vapi.nat44_user_session_dump(user.ip4n, 0)
+            self.assertEqual(len(sessions), 3)
+            self.assertTrue(sessions[0].ext_host_valid)
+            self.vapi.nat44_del_session(
+                sessions[0].inside_ip_address,
+                sessions[0].inside_port,
+                sessions[0].protocol,
+                ext_host_address=sessions[0].ext_host_address,
+                ext_host_port=sessions[0].ext_host_port)
+            sessions = self.vapi.nat44_user_session_dump(user.ip4n, 0)
+            self.assertEqual(len(sessions), 2)
+
+        finally:
+            self.vapi.nat44_forwarding_enable_disable(0)
+            self.vapi.nat44_add_del_static_mapping(local_ip=real_ip,
+                                                   external_ip=alias_ip,
+                                                   is_add=0)
+
+    def test_static_lb(self):
+        """ NAT44 local service load balancing """
+        external_addr_n = socket.inet_pton(socket.AF_INET, self.nat_addr)
+        external_port = 80
+        local_port = 8080
+        server1 = self.pg0.remote_hosts[0]
+        server2 = self.pg0.remote_hosts[1]
+
+        locals = [{'addr': server1.ip4n,
+                   'port': local_port,
+                   'probability': 70,
+                   'vrf_id': 0},
+                  {'addr': server2.ip4n,
+                   'port': local_port,
+                   'probability': 30,
+                   'vrf_id': 0}]
+
+        self.nat44_add_address(self.nat_addr)
+        self.vapi.nat44_add_del_lb_static_mapping(external_addr_n,
+                                                  external_port,
+                                                  IP_PROTOS.tcp,
+                                                  local_num=len(locals),
+                                                  locals=locals)
+        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
+                                                  is_inside=0)
+
+        # from client to service
+        p = (Ether(src=self.pg1.remote_mac, dst=self.pg1.local_mac) /
+             IP(src=self.pg1.remote_ip4, dst=self.nat_addr) /
+             TCP(sport=12345, dport=external_port))
+        self.pg1.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg0.get_capture(1)
+        p = capture[0]
+        server = None
+        try:
+            ip = p[IP]
+            tcp = p[TCP]
+            self.assertIn(ip.dst, [server1.ip4, server2.ip4])
+            if ip.dst == server1.ip4:
+                server = server1
+            else:
+                server = server2
+            self.assertEqual(tcp.dport, local_port)
+            self.assert_packet_checksums_valid(p)
+        except:
+            self.logger.error(ppp("Unexpected or invalid packet:", p))
+            raise
+
+        # from service back to client
+        p = (Ether(src=server.mac, dst=self.pg0.local_mac) /
+             IP(src=server.ip4, dst=self.pg1.remote_ip4) /
+             TCP(sport=local_port, dport=12345))
+        self.pg0.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg1.get_capture(1)
+        p = capture[0]
+        try:
+            ip = p[IP]
+            tcp = p[TCP]
+            self.assertEqual(ip.src, self.nat_addr)
+            self.assertEqual(tcp.sport, external_port)
+            self.assert_packet_checksums_valid(p)
+        except:
+            self.logger.error(ppp("Unexpected or invalid packet:", p))
+            raise
+
+        sessions = self.vapi.nat44_user_session_dump(server.ip4n, 0)
+        self.assertEqual(len(sessions), 1)
+        self.assertTrue(sessions[0].ext_host_valid)
+        self.vapi.nat44_del_session(
+            sessions[0].inside_ip_address,
+            sessions[0].inside_port,
+            sessions[0].protocol,
+            ext_host_address=sessions[0].ext_host_address,
+            ext_host_port=sessions[0].ext_host_port)
+        sessions = self.vapi.nat44_user_session_dump(server.ip4n, 0)
+        self.assertEqual(len(sessions), 0)
+
+    @unittest.skipUnless(running_extended_tests, "part of extended tests")
+    def test_static_lb_multi_clients(self):
+        """ NAT44 local service load balancing - multiple clients"""
+
+        external_addr_n = socket.inet_pton(socket.AF_INET, self.nat_addr)
+        external_port = 80
+        local_port = 8080
+        server1 = self.pg0.remote_hosts[0]
+        server2 = self.pg0.remote_hosts[1]
+        server3 = self.pg0.remote_hosts[2]
+
+        locals = [{'addr': server1.ip4n,
+                   'port': local_port,
+                   'probability': 90,
+                   'vrf_id': 0},
+                  {'addr': server2.ip4n,
+                   'port': local_port,
+                   'probability': 10,
+                   'vrf_id': 0}]
+
+        self.nat44_add_address(self.nat_addr)
+        self.vapi.nat44_add_del_lb_static_mapping(external_addr_n,
+                                                  external_port,
+                                                  IP_PROTOS.tcp,
+                                                  local_num=len(locals),
+                                                  locals=locals)
+        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
+                                                  is_inside=0)
+
+        server1_n = 0
+        server2_n = 0
+        clients = ip4_range(self.pg1.remote_ip4, 10, 50)
+        pkts = []
+        for client in clients:
+            p = (Ether(src=self.pg1.remote_mac, dst=self.pg1.local_mac) /
+                 IP(src=client, dst=self.nat_addr) /
+                 TCP(sport=12345, dport=external_port))
+            pkts.append(p)
+        self.pg1.add_stream(pkts)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg0.get_capture(len(pkts))
+        for p in capture:
+            if p[IP].dst == server1.ip4:
+                server1_n += 1
+            else:
+                server2_n += 1
+        self.assertGreater(server1_n, server2_n)
+
+        # add new back-end
+        self.vapi.nat44_lb_static_mapping_add_del_local(external_addr_n,
+                                                        external_port,
+                                                        server3.ip4n,
+                                                        local_port,
+                                                        IP_PROTOS.tcp,
+                                                        20)
+        server1_n = 0
+        server2_n = 0
+        server3_n = 0
+        clients = ip4_range(self.pg1.remote_ip4, 60, 110)
+        pkts = []
+        for client in clients:
+            p = (Ether(src=self.pg1.remote_mac, dst=self.pg1.local_mac) /
+                 IP(src=client, dst=self.nat_addr) /
+                 TCP(sport=12346, dport=external_port))
+            pkts.append(p)
+        self.assertGreater(len(pkts), 0)
+        self.pg1.add_stream(pkts)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg0.get_capture(len(pkts))
+        for p in capture:
+            if p[IP].dst == server1.ip4:
+                server1_n += 1
+            elif p[IP].dst == server2.ip4:
+                server2_n += 1
+            else:
+                server3_n += 1
+        self.assertGreater(server1_n, 0)
+        self.assertGreater(server2_n, 0)
+        self.assertGreater(server3_n, 0)
+
+        # remove one back-end
+        self.vapi.nat44_lb_static_mapping_add_del_local(external_addr_n,
+                                                        external_port,
+                                                        server2.ip4n,
+                                                        local_port,
+                                                        IP_PROTOS.tcp,
+                                                        10,
+                                                        is_add=0)
+        server1_n = 0
+        server2_n = 0
+        server3_n = 0
+        self.pg1.add_stream(pkts)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg0.get_capture(len(pkts))
+        for p in capture:
+            if p[IP].dst == server1.ip4:
+                server1_n += 1
+            elif p[IP].dst == server2.ip4:
+                server2_n += 1
+            else:
+                server3_n += 1
+        self.assertGreater(server1_n, 0)
+        self.assertEqual(server2_n, 0)
+        self.assertGreater(server3_n, 0)
+
+    def test_static_lb_2(self):
+        """ NAT44 local service load balancing (asymmetrical rule) """
+        external_addr_n = socket.inet_pton(socket.AF_INET, self.nat_addr)
+        external_port = 80
+        local_port = 8080
+        server1 = self.pg0.remote_hosts[0]
+        server2 = self.pg0.remote_hosts[1]
+
+        locals = [{'addr': server1.ip4n,
+                   'port': local_port,
+                   'probability': 70,
+                   'vrf_id': 0},
+                  {'addr': server2.ip4n,
+                   'port': local_port,
+                   'probability': 30,
+                   'vrf_id': 0}]
+
+        self.vapi.nat44_forwarding_enable_disable(1)
+        self.vapi.nat44_add_del_lb_static_mapping(external_addr_n,
+                                                  external_port,
+                                                  IP_PROTOS.tcp,
+                                                  out2in_only=1,
+                                                  local_num=len(locals),
+                                                  locals=locals)
+        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
+                                                  is_inside=0)
+
+        # from client to service
+        p = (Ether(src=self.pg1.remote_mac, dst=self.pg1.local_mac) /
+             IP(src=self.pg1.remote_ip4, dst=self.nat_addr) /
+             TCP(sport=12345, dport=external_port))
+        self.pg1.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg0.get_capture(1)
+        p = capture[0]
+        server = None
+        try:
+            ip = p[IP]
+            tcp = p[TCP]
+            self.assertIn(ip.dst, [server1.ip4, server2.ip4])
+            if ip.dst == server1.ip4:
+                server = server1
+            else:
+                server = server2
+            self.assertEqual(tcp.dport, local_port)
+            self.assert_packet_checksums_valid(p)
+        except:
+            self.logger.error(ppp("Unexpected or invalid packet:", p))
+            raise
+
+        # from service back to client
+        p = (Ether(src=server.mac, dst=self.pg0.local_mac) /
+             IP(src=server.ip4, dst=self.pg1.remote_ip4) /
+             TCP(sport=local_port, dport=12345))
+        self.pg0.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg1.get_capture(1)
+        p = capture[0]
+        try:
+            ip = p[IP]
+            tcp = p[TCP]
+            self.assertEqual(ip.src, self.nat_addr)
+            self.assertEqual(tcp.sport, external_port)
+            self.assert_packet_checksums_valid(p)
+        except:
+            self.logger.error(ppp("Unexpected or invalid packet:", p))
+            raise
+
+        # from client to server (no translation)
+        p = (Ether(src=self.pg1.remote_mac, dst=self.pg1.local_mac) /
+             IP(src=self.pg1.remote_ip4, dst=server1.ip4) /
+             TCP(sport=12346, dport=local_port))
+        self.pg1.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg0.get_capture(1)
+        p = capture[0]
+        server = None
+        try:
+            ip = p[IP]
+            tcp = p[TCP]
+            self.assertEqual(ip.dst, server1.ip4)
+            self.assertEqual(tcp.dport, local_port)
+            self.assert_packet_checksums_valid(p)
+        except:
+            self.logger.error(ppp("Unexpected or invalid packet:", p))
+            raise
+
+        # from service back to client (no translation)
+        p = (Ether(src=server1.mac, dst=self.pg0.local_mac) /
+             IP(src=server1.ip4, dst=self.pg1.remote_ip4) /
+             TCP(sport=local_port, dport=12346))
+        self.pg0.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg1.get_capture(1)
+        p = capture[0]
+        try:
+            ip = p[IP]
+            tcp = p[TCP]
+            self.assertEqual(ip.src, server1.ip4)
+            self.assertEqual(tcp.sport, local_port)
+            self.assert_packet_checksums_valid(p)
+        except:
+            self.logger.error(ppp("Unexpected or invalid packet:", p))
+            raise
+
+    def test_lb_affinity(self):
+        """ NAT44 local service load balancing affinity """
+        external_addr_n = socket.inet_pton(socket.AF_INET, self.nat_addr)
+        external_port = 80
+        local_port = 8080
+        server1 = self.pg0.remote_hosts[0]
+        server2 = self.pg0.remote_hosts[1]
+
+        locals = [{'addr': server1.ip4n,
+                   'port': local_port,
+                   'probability': 50,
+                   'vrf_id': 0},
+                  {'addr': server2.ip4n,
+                   'port': local_port,
+                   'probability': 50,
+                   'vrf_id': 0}]
+
+        self.nat44_add_address(self.nat_addr)
+        self.vapi.nat44_add_del_lb_static_mapping(external_addr_n,
+                                                  external_port,
+                                                  IP_PROTOS.tcp,
+                                                  affinity=10800,
+                                                  local_num=len(locals),
+                                                  locals=locals)
+        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
+                                                  is_inside=0)
 
-        # NAT44 address
-        p = (Ether(src=self.pg1.remote_mac, dst='ff:ff:ff:ff:ff:ff') /
-             ARP(op=ARP.who_has, pdst=self.nat_addr,
-                 psrc=self.pg1.remote_ip4, hwsrc=self.pg1.remote_mac))
+        p = (Ether(dst=self.pg1.local_mac, src=self.pg1.remote_mac) /
+             IP(src=self.pg1.remote_ip4, dst=self.nat_addr) /
+             TCP(sport=1025, dport=external_port))
         self.pg1.add_stream(p)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        capture = self.pg1.get_capture(1)
-        self.assertTrue(capture[0].haslayer(ARP))
-        self.assertTrue(capture[0][ARP].op, ARP.is_at)
+        capture = self.pg0.get_capture(1)
+        backend = capture[0][IP].dst
+
+        sessions = self.vapi.nat44_user_session_dump(
+            socket.inet_pton(socket.AF_INET, backend), 0)
+        self.assertEqual(len(sessions), 1)
+        self.assertTrue(sessions[0].ext_host_valid)
+        self.vapi.nat44_del_session(
+            sessions[0].inside_ip_address,
+            sessions[0].inside_port,
+            sessions[0].protocol,
+            ext_host_address=sessions[0].ext_host_address,
+            ext_host_port=sessions[0].ext_host_port)
 
-        # 1:1 NAT address
-        p = (Ether(src=self.pg1.remote_mac, dst='ff:ff:ff:ff:ff:ff') /
-             ARP(op=ARP.who_has, pdst=static_addr,
-                 psrc=self.pg1.remote_ip4, hwsrc=self.pg1.remote_mac))
-        self.pg1.add_stream(p)
+        pkts = []
+        for port in range(1030, 1100):
+            p = (Ether(dst=self.pg1.local_mac, src=self.pg1.remote_mac) /
+                 IP(src=self.pg1.remote_ip4, dst=self.nat_addr) /
+                 TCP(sport=port, dport=external_port))
+            pkts.append(p)
+        self.pg1.add_stream(pkts)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        capture = self.pg1.get_capture(1)
-        self.assertTrue(capture[0].haslayer(ARP))
-        self.assertTrue(capture[0][ARP].op, ARP.is_at)
+        capture = self.pg0.get_capture(len(pkts))
+        for p in capture:
+            self.assertEqual(p[IP].dst, backend)
 
-        # send ARP to non-NAT44 interface
-        p = (Ether(src=self.pg2.remote_mac, dst='ff:ff:ff:ff:ff:ff') /
-             ARP(op=ARP.who_has, pdst=self.nat_addr,
-                 psrc=self.pg2.remote_ip4, hwsrc=self.pg2.remote_mac))
-        self.pg2.add_stream(p)
+    def test_unknown_proto(self):
+        """ NAT44 translate packet with unknown protocol """
+        self.nat44_add_address(self.nat_addr)
+        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
+                                                  is_inside=0)
+
+        # in2out
+        p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
+             IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4) /
+             TCP(sport=self.tcp_port_in, dport=20))
+        self.pg0.add_stream(p)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        capture = self.pg1.get_capture(0)
-
-        # remove addresses and verify
-        self.nat44_add_address(self.nat_addr, is_add=0)
-        self.nat44_add_static_mapping(self.pg0.remote_ip4, static_addr,
-                                      is_add=0)
+        p = self.pg1.get_capture(1)
 
-        p = (Ether(src=self.pg1.remote_mac, dst='ff:ff:ff:ff:ff:ff') /
-             ARP(op=ARP.who_has, pdst=self.nat_addr,
-                 psrc=self.pg1.remote_ip4, hwsrc=self.pg1.remote_mac))
-        self.pg1.add_stream(p)
+        p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
+             IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4) /
+             GRE() /
+             IP(src=self.pg2.remote_ip4, dst=self.pg2.remote_ip4) /
+             TCP(sport=1234, dport=1234))
+        self.pg0.add_stream(p)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        capture = self.pg1.get_capture(0)
+        p = self.pg1.get_capture(1)
+        packet = p[0]
+        try:
+            self.assertEqual(packet[IP].src, self.nat_addr)
+            self.assertEqual(packet[IP].dst, self.pg1.remote_ip4)
+            self.assertEqual(packet.haslayer(GRE), 1)
+            self.assert_packet_checksums_valid(packet)
+        except:
+            self.logger.error(ppp("Unexpected or invalid packet:", packet))
+            raise
 
-        p = (Ether(src=self.pg1.remote_mac, dst='ff:ff:ff:ff:ff:ff') /
-             ARP(op=ARP.who_has, pdst=static_addr,
-                 psrc=self.pg1.remote_ip4, hwsrc=self.pg1.remote_mac))
+        # out2in
+        p = (Ether(dst=self.pg1.local_mac, src=self.pg1.remote_mac) /
+             IP(src=self.pg1.remote_ip4, dst=self.nat_addr) /
+             GRE() /
+             IP(src=self.pg2.remote_ip4, dst=self.pg2.remote_ip4) /
+             TCP(sport=1234, dport=1234))
         self.pg1.add_stream(p)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        capture = self.pg1.get_capture(0)
-
-    def test_vrf_mode(self):
-        """ NAT44 tenant VRF aware address pool mode """
-
-        vrf_id1 = 1
-        vrf_id2 = 2
-        nat_ip1 = "10.0.0.10"
-        nat_ip2 = "10.0.0.11"
+        p = self.pg0.get_capture(1)
+        packet = p[0]
+        try:
+            self.assertEqual(packet[IP].src, self.pg1.remote_ip4)
+            self.assertEqual(packet[IP].dst, self.pg0.remote_ip4)
+            self.assertEqual(packet.haslayer(GRE), 1)
+            self.assert_packet_checksums_valid(packet)
+        except:
+            self.logger.error(ppp("Unexpected or invalid packet:", packet))
+            raise
 
-        self.pg0.unconfig_ip4()
-        self.pg1.unconfig_ip4()
-        self.vapi.ip_table_add_del(vrf_id1, is_add=1)
-        self.vapi.ip_table_add_del(vrf_id2, is_add=1)
-        self.pg0.set_table_ip4(vrf_id1)
-        self.pg1.set_table_ip4(vrf_id2)
-        self.pg0.config_ip4()
-        self.pg1.config_ip4()
+    def test_hairpinning_unknown_proto(self):
+        """ NAT44 translate packet with unknown protocol - hairpinning """
+        host = self.pg0.remote_hosts[0]
+        server = self.pg0.remote_hosts[1]
+        host_in_port = 1234
+        server_out_port = 8765
+        server_nat_ip = "10.0.0.11"
 
-        self.nat44_add_address(nat_ip1, vrf_id=vrf_id1)
-        self.nat44_add_address(nat_ip2, vrf_id=vrf_id2)
+        self.nat44_add_address(self.nat_addr)
         self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
-        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index)
-        self.vapi.nat44_interface_add_del_feature(self.pg2.sw_if_index,
+        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
                                                   is_inside=0)
 
-        # first VRF
-        pkts = self.create_stream_in(self.pg0, self.pg2)
-        self.pg0.add_stream(pkts)
+        # add static mapping for server
+        self.nat44_add_static_mapping(server.ip4, server_nat_ip)
+
+        # host to server
+        p = (Ether(src=host.mac, dst=self.pg0.local_mac) /
+             IP(src=host.ip4, dst=server_nat_ip) /
+             TCP(sport=host_in_port, dport=server_out_port))
+        self.pg0.add_stream(p)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        capture = self.pg2.get_capture(len(pkts))
-        self.verify_capture_out(capture, nat_ip1)
+        self.pg0.get_capture(1)
 
-        # second VRF
-        pkts = self.create_stream_in(self.pg1, self.pg2)
-        self.pg1.add_stream(pkts)
+        p = (Ether(dst=self.pg0.local_mac, src=host.mac) /
+             IP(src=host.ip4, dst=server_nat_ip) /
+             GRE() /
+             IP(src=self.pg2.remote_ip4, dst=self.pg2.remote_ip4) /
+             TCP(sport=1234, dport=1234))
+        self.pg0.add_stream(p)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        capture = self.pg2.get_capture(len(pkts))
-        self.verify_capture_out(capture, nat_ip2)
-
-        self.pg0.unconfig_ip4()
-        self.pg1.unconfig_ip4()
-        self.pg0.set_table_ip4(0)
-        self.pg1.set_table_ip4(0)
-        self.vapi.ip_table_add_del(vrf_id1, is_add=0)
-        self.vapi.ip_table_add_del(vrf_id2, is_add=0)
+        p = self.pg0.get_capture(1)
+        packet = p[0]
+        try:
+            self.assertEqual(packet[IP].src, self.nat_addr)
+            self.assertEqual(packet[IP].dst, server.ip4)
+            self.assertEqual(packet.haslayer(GRE), 1)
+            self.assert_packet_checksums_valid(packet)
+        except:
+            self.logger.error(ppp("Unexpected or invalid packet:", packet))
+            raise
 
-    def test_vrf_feature_independent(self):
-        """ NAT44 tenant VRF independent address pool mode """
+        # server to host
+        p = (Ether(dst=self.pg0.local_mac, src=server.mac) /
+             IP(src=server.ip4, dst=self.nat_addr) /
+             GRE() /
+             IP(src=self.pg2.remote_ip4, dst=self.pg2.remote_ip4) /
+             TCP(sport=1234, dport=1234))
+        self.pg0.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        p = self.pg0.get_capture(1)
+        packet = p[0]
+        try:
+            self.assertEqual(packet[IP].src, server_nat_ip)
+            self.assertEqual(packet[IP].dst, host.ip4)
+            self.assertEqual(packet.haslayer(GRE), 1)
+            self.assert_packet_checksums_valid(packet)
+        except:
+            self.logger.error(ppp("Unexpected or invalid packet:", packet))
+            raise
 
-        nat_ip1 = "10.0.0.10"
-        nat_ip2 = "10.0.0.11"
+    def test_output_feature_and_service(self):
+        """ NAT44 interface output feature and services """
+        external_addr = '1.2.3.4'
+        external_port = 80
+        local_port = 8080
 
-        self.nat44_add_address(nat_ip1)
-        self.nat44_add_address(nat_ip2, vrf_id=99)
+        self.vapi.nat44_forwarding_enable_disable(1)
+        self.nat44_add_address(self.nat_addr)
+        self.vapi.nat44_add_del_identity_mapping(ip=self.pg1.remote_ip4n)
+        self.nat44_add_static_mapping(self.pg0.remote_ip4, external_addr,
+                                      local_port, external_port,
+                                      proto=IP_PROTOS.tcp, out2in_only=1)
         self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
-        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index)
-        self.vapi.nat44_interface_add_del_feature(self.pg2.sw_if_index,
+        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index,
                                                   is_inside=0)
+        self.vapi.nat44_interface_add_del_output_feature(self.pg1.sw_if_index,
+                                                         is_inside=0)
 
-        # first VRF
-        pkts = self.create_stream_in(self.pg0, self.pg2)
-        self.pg0.add_stream(pkts)
+        # from client to service
+        p = (Ether(src=self.pg1.remote_mac, dst=self.pg1.local_mac) /
+             IP(src=self.pg1.remote_ip4, dst=external_addr) /
+             TCP(sport=12345, dport=external_port))
+        self.pg1.add_stream(p)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        capture = self.pg2.get_capture(len(pkts))
-        self.verify_capture_out(capture, nat_ip1)
+        capture = self.pg0.get_capture(1)
+        p = capture[0]
+        try:
+            ip = p[IP]
+            tcp = p[TCP]
+            self.assertEqual(ip.dst, self.pg0.remote_ip4)
+            self.assertEqual(tcp.dport, local_port)
+            self.assert_packet_checksums_valid(p)
+        except:
+            self.logger.error(ppp("Unexpected or invalid packet:", p))
+            raise
 
-        # second VRF
-        pkts = self.create_stream_in(self.pg1, self.pg2)
-        self.pg1.add_stream(pkts)
+        # from service back to client
+        p = (Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac) /
+             IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4) /
+             TCP(sport=local_port, dport=12345))
+        self.pg0.add_stream(p)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        capture = self.pg2.get_capture(len(pkts))
-        self.verify_capture_out(capture, nat_ip1)
-
-    def test_dynamic_ipless_interfaces(self):
-        """ NAT44 interfaces without configured IP address """
+        capture = self.pg1.get_capture(1)
+        p = capture[0]
+        try:
+            ip = p[IP]
+            tcp = p[TCP]
+            self.assertEqual(ip.src, external_addr)
+            self.assertEqual(tcp.sport, external_port)
+            self.assert_packet_checksums_valid(p)
+        except:
+            self.logger.error(ppp("Unexpected or invalid packet:", p))
+            raise
 
-        self.vapi.ip_neighbor_add_del(self.pg7.sw_if_index,
-                                      mactobinary(self.pg7.remote_mac),
-                                      self.pg7.remote_ip4n,
-                                      is_static=1)
-        self.vapi.ip_neighbor_add_del(self.pg8.sw_if_index,
-                                      mactobinary(self.pg8.remote_mac),
-                                      self.pg8.remote_ip4n,
-                                      is_static=1)
+        # from local network host to external network
+        pkts = self.create_stream_in(self.pg0, self.pg1)
+        self.pg0.add_stream(pkts)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg1.get_capture(len(pkts))
+        self.verify_capture_out(capture)
+        pkts = self.create_stream_in(self.pg0, self.pg1)
+        self.pg0.add_stream(pkts)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg1.get_capture(len(pkts))
+        self.verify_capture_out(capture)
 
-        self.vapi.ip_add_del_route(dst_address=self.pg7.remote_ip4n,
-                                   dst_address_length=32,
-                                   next_hop_address=self.pg7.remote_ip4n,
-                                   next_hop_sw_if_index=self.pg7.sw_if_index)
-        self.vapi.ip_add_del_route(dst_address=self.pg8.remote_ip4n,
-                                   dst_address_length=32,
-                                   next_hop_address=self.pg8.remote_ip4n,
-                                   next_hop_sw_if_index=self.pg8.sw_if_index)
+        # from external network back to local network host
+        pkts = self.create_stream_out(self.pg1)
+        self.pg1.add_stream(pkts)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg0.get_capture(len(pkts))
+        self.verify_capture_in(capture, self.pg0)
 
+    def test_output_feature_and_service2(self):
+        """ NAT44 interface output feature and service host direct access """
+        self.vapi.nat44_forwarding_enable_disable(1)
         self.nat44_add_address(self.nat_addr)
-        self.vapi.nat44_interface_add_del_feature(self.pg7.sw_if_index)
-        self.vapi.nat44_interface_add_del_feature(self.pg8.sw_if_index,
-                                                  is_inside=0)
+        self.vapi.nat44_interface_add_del_output_feature(self.pg1.sw_if_index,
+                                                         is_inside=0)
 
-        # in2out
-        pkts = self.create_stream_in(self.pg7, self.pg8)
-        self.pg7.add_stream(pkts)
+        # session initiaded from service host - translate
+        pkts = self.create_stream_in(self.pg0, self.pg1)
+        self.pg0.add_stream(pkts)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        capture = self.pg8.get_capture(len(pkts))
+        capture = self.pg1.get_capture(len(pkts))
         self.verify_capture_out(capture)
 
-        # out2in
-        pkts = self.create_stream_out(self.pg8, self.nat_addr)
-        self.pg8.add_stream(pkts)
+        pkts = self.create_stream_out(self.pg1)
+        self.pg1.add_stream(pkts)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        capture = self.pg7.get_capture(len(pkts))
-        self.verify_capture_in(capture, self.pg7)
-
-    def test_static_ipless_interfaces(self):
-        """ NAT44 interfaces without configured IP address - 1:1 NAT """
-
-        self.vapi.ip_neighbor_add_del(self.pg7.sw_if_index,
-                                      mactobinary(self.pg7.remote_mac),
-                                      self.pg7.remote_ip4n,
-                                      is_static=1)
-        self.vapi.ip_neighbor_add_del(self.pg8.sw_if_index,
-                                      mactobinary(self.pg8.remote_mac),
-                                      self.pg8.remote_ip4n,
-                                      is_static=1)
-
-        self.vapi.ip_add_del_route(dst_address=self.pg7.remote_ip4n,
-                                   dst_address_length=32,
-                                   next_hop_address=self.pg7.remote_ip4n,
-                                   next_hop_sw_if_index=self.pg7.sw_if_index)
-        self.vapi.ip_add_del_route(dst_address=self.pg8.remote_ip4n,
-                                   dst_address_length=32,
-                                   next_hop_address=self.pg8.remote_ip4n,
-                                   next_hop_sw_if_index=self.pg8.sw_if_index)
-
-        self.nat44_add_static_mapping(self.pg7.remote_ip4, self.nat_addr)
-        self.vapi.nat44_interface_add_del_feature(self.pg7.sw_if_index)
-        self.vapi.nat44_interface_add_del_feature(self.pg8.sw_if_index,
-                                                  is_inside=0)
+        capture = self.pg0.get_capture(len(pkts))
+        self.verify_capture_in(capture, self.pg0)
 
-        # out2in
-        pkts = self.create_stream_out(self.pg8)
-        self.pg8.add_stream(pkts)
+        # session initiaded from remote host - do not translate
+        self.tcp_port_in = 60303
+        self.udp_port_in = 60304
+        self.icmp_id_in = 60305
+        pkts = self.create_stream_out(self.pg1,
+                                      self.pg0.remote_ip4,
+                                      use_inside_ports=True)
+        self.pg1.add_stream(pkts)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        capture = self.pg7.get_capture(len(pkts))
-        self.verify_capture_in(capture, self.pg7)
+        capture = self.pg0.get_capture(len(pkts))
+        self.verify_capture_in(capture, self.pg0)
 
-        # in2out
-        pkts = self.create_stream_in(self.pg7, self.pg8)
-        self.pg7.add_stream(pkts)
+        pkts = self.create_stream_in(self.pg0, self.pg1)
+        self.pg0.add_stream(pkts)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        capture = self.pg8.get_capture(len(pkts))
-        self.verify_capture_out(capture, self.nat_addr, True)
-
-    def test_static_with_port_ipless_interfaces(self):
-        """ NAT44 interfaces without configured IP address - 1:1 NAPT """
-
-        self.tcp_port_out = 30606
-        self.udp_port_out = 30607
-        self.icmp_id_out = 30608
-
-        self.vapi.ip_neighbor_add_del(self.pg7.sw_if_index,
-                                      mactobinary(self.pg7.remote_mac),
-                                      self.pg7.remote_ip4n,
-                                      is_static=1)
-        self.vapi.ip_neighbor_add_del(self.pg8.sw_if_index,
-                                      mactobinary(self.pg8.remote_mac),
-                                      self.pg8.remote_ip4n,
-                                      is_static=1)
+        capture = self.pg1.get_capture(len(pkts))
+        self.verify_capture_out(capture, nat_ip=self.pg0.remote_ip4,
+                                same_port=True)
 
-        self.vapi.ip_add_del_route(dst_address=self.pg7.remote_ip4n,
-                                   dst_address_length=32,
-                                   next_hop_address=self.pg7.remote_ip4n,
-                                   next_hop_sw_if_index=self.pg7.sw_if_index)
-        self.vapi.ip_add_del_route(dst_address=self.pg8.remote_ip4n,
-                                   dst_address_length=32,
-                                   next_hop_address=self.pg8.remote_ip4n,
-                                   next_hop_sw_if_index=self.pg8.sw_if_index)
+    def test_output_feature_and_service3(self):
+        """ NAT44 interface output feature and DST NAT """
+        external_addr = '1.2.3.4'
+        external_port = 80
+        local_port = 8080
 
+        self.vapi.nat44_forwarding_enable_disable(1)
         self.nat44_add_address(self.nat_addr)
-        self.nat44_add_static_mapping(self.pg7.remote_ip4, self.nat_addr,
-                                      self.tcp_port_in, self.tcp_port_out,
-                                      proto=IP_PROTOS.tcp)
-        self.nat44_add_static_mapping(self.pg7.remote_ip4, self.nat_addr,
-                                      self.udp_port_in, self.udp_port_out,
-                                      proto=IP_PROTOS.udp)
-        self.nat44_add_static_mapping(self.pg7.remote_ip4, self.nat_addr,
-                                      self.icmp_id_in, self.icmp_id_out,
-                                      proto=IP_PROTOS.icmp)
-        self.vapi.nat44_interface_add_del_feature(self.pg7.sw_if_index)
-        self.vapi.nat44_interface_add_del_feature(self.pg8.sw_if_index,
+        self.nat44_add_static_mapping(self.pg1.remote_ip4, external_addr,
+                                      local_port, external_port,
+                                      proto=IP_PROTOS.tcp, out2in_only=1)
+        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index,
                                                   is_inside=0)
+        self.vapi.nat44_interface_add_del_output_feature(self.pg1.sw_if_index,
+                                                         is_inside=0)
 
-        # out2in
-        pkts = self.create_stream_out(self.pg8)
-        self.pg8.add_stream(pkts)
+        p = (Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac) /
+             IP(src=self.pg0.remote_ip4, dst=external_addr) /
+             TCP(sport=12345, dport=external_port))
+        self.pg0.add_stream(p)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        capture = self.pg7.get_capture(len(pkts))
-        self.verify_capture_in(capture, self.pg7)
+        capture = self.pg1.get_capture(1)
+        p = capture[0]
+        try:
+            ip = p[IP]
+            tcp = p[TCP]
+            self.assertEqual(ip.src, self.pg0.remote_ip4)
+            self.assertEqual(tcp.sport, 12345)
+            self.assertEqual(ip.dst, self.pg1.remote_ip4)
+            self.assertEqual(tcp.dport, local_port)
+            self.assert_packet_checksums_valid(p)
+        except:
+            self.logger.error(ppp("Unexpected or invalid packet:", p))
+            raise
 
-        # in2out
-        pkts = self.create_stream_in(self.pg7, self.pg8)
-        self.pg7.add_stream(pkts)
+        p = (Ether(src=self.pg1.remote_mac, dst=self.pg1.local_mac) /
+             IP(src=self.pg1.remote_ip4, dst=self.pg0.remote_ip4) /
+             TCP(sport=local_port, dport=12345))
+        self.pg1.add_stream(p)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        capture = self.pg8.get_capture(len(pkts))
-        self.verify_capture_out(capture)
+        capture = self.pg0.get_capture(1)
+        p = capture[0]
+        try:
+            ip = p[IP]
+            tcp = p[TCP]
+            self.assertEqual(ip.src, external_addr)
+            self.assertEqual(tcp.sport, external_port)
+            self.assertEqual(ip.dst, self.pg0.remote_ip4)
+            self.assertEqual(tcp.dport, 12345)
+            self.assert_packet_checksums_valid(p)
+        except:
+            self.logger.error(ppp("Unexpected or invalid packet:", p))
+            raise
 
-    def test_static_unknown_proto(self):
-        """ 1:1 NAT translate packet with unknown protocol """
-        nat_ip = "10.0.0.10"
-        self.nat44_add_static_mapping(self.pg0.remote_ip4, nat_ip)
-        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
-        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
+    def test_next_src_nat(self):
+        """ On way back forward packet to nat44-in2out node. """
+        twice_nat_addr = '10.0.1.3'
+        external_port = 80
+        local_port = 8080
+        post_twice_nat_port = 0
+
+        self.vapi.nat44_forwarding_enable_disable(1)
+        self.nat44_add_address(twice_nat_addr, twice_nat=1)
+        self.nat44_add_static_mapping(self.pg6.remote_ip4, self.pg1.remote_ip4,
+                                      local_port, external_port,
+                                      proto=IP_PROTOS.tcp, out2in_only=1,
+                                      self_twice_nat=1, vrf_id=1)
+        self.vapi.nat44_interface_add_del_feature(self.pg6.sw_if_index,
                                                   is_inside=0)
 
-        # in2out
-        p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
-             IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4) /
-             GRE() /
-             IP(src=self.pg2.remote_ip4, dst=self.pg3.remote_ip4) /
-             TCP(sport=1234, dport=1234))
-        self.pg0.add_stream(p)
+        p = (Ether(src=self.pg6.remote_mac, dst=self.pg6.local_mac) /
+             IP(src=self.pg6.remote_ip4, dst=self.pg1.remote_ip4) /
+             TCP(sport=12345, dport=external_port))
+        self.pg6.add_stream(p)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        p = self.pg1.get_capture(1)
-        packet = p[0]
+        capture = self.pg6.get_capture(1)
+        p = capture[0]
         try:
-            self.assertEqual(packet[IP].src, nat_ip)
-            self.assertEqual(packet[IP].dst, self.pg1.remote_ip4)
-            self.assertTrue(packet.haslayer(GRE))
-            self.check_ip_checksum(packet)
+            ip = p[IP]
+            tcp = p[TCP]
+            self.assertEqual(ip.src, twice_nat_addr)
+            self.assertNotEqual(tcp.sport, 12345)
+            post_twice_nat_port = tcp.sport
+            self.assertEqual(ip.dst, self.pg6.remote_ip4)
+            self.assertEqual(tcp.dport, local_port)
+            self.assert_packet_checksums_valid(p)
         except:
-            self.logger.error(ppp("Unexpected or invalid packet:", packet))
+            self.logger.error(ppp("Unexpected or invalid packet:", p))
             raise
 
-        # out2in
-        p = (Ether(dst=self.pg1.local_mac, src=self.pg1.remote_mac) /
-             IP(src=self.pg1.remote_ip4, dst=nat_ip) /
-             GRE() /
-             IP(src=self.pg3.remote_ip4, dst=self.pg2.remote_ip4) /
-             TCP(sport=1234, dport=1234))
-        self.pg1.add_stream(p)
+        p = (Ether(src=self.pg6.remote_mac, dst=self.pg6.local_mac) /
+             IP(src=self.pg6.remote_ip4, dst=twice_nat_addr) /
+             TCP(sport=local_port, dport=post_twice_nat_port))
+        self.pg6.add_stream(p)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        p = self.pg0.get_capture(1)
-        packet = p[0]
+        capture = self.pg6.get_capture(1)
+        p = capture[0]
         try:
-            self.assertEqual(packet[IP].src, self.pg1.remote_ip4)
-            self.assertEqual(packet[IP].dst, self.pg0.remote_ip4)
-            self.assertTrue(packet.haslayer(GRE))
-            self.check_ip_checksum(packet)
+            ip = p[IP]
+            tcp = p[TCP]
+            self.assertEqual(ip.src, self.pg1.remote_ip4)
+            self.assertEqual(tcp.sport, external_port)
+            self.assertEqual(ip.dst, self.pg6.remote_ip4)
+            self.assertEqual(tcp.dport, 12345)
+            self.assert_packet_checksums_valid(p)
         except:
-            self.logger.error(ppp("Unexpected or invalid packet:", packet))
+            self.logger.error(ppp("Unexpected or invalid packet:", p))
             raise
 
-    def test_hairpinning_static_unknown_proto(self):
-        """ 1:1 NAT translate packet with unknown protocol - hairpinning """
+    def twice_nat_common(self, self_twice_nat=False, same_pg=False, lb=False,
+                         client_id=None):
+        twice_nat_addr = '10.0.1.3'
 
-        host = self.pg0.remote_hosts[0]
-        server = self.pg0.remote_hosts[1]
+        port_in = 8080
+        if lb:
+            if not same_pg:
+                port_in1 = port_in
+                port_in2 = port_in
+            else:
+                port_in1 = port_in+1
+                port_in2 = port_in+2
 
-        host_nat_ip = "10.0.0.10"
-        server_nat_ip = "10.0.0.11"
+        port_out = 80
+        eh_port_out = 4567
 
-        self.nat44_add_static_mapping(host.ip4, host_nat_ip)
-        self.nat44_add_static_mapping(server.ip4, server_nat_ip)
-        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
-        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
+        server1 = self.pg0.remote_hosts[0]
+        server2 = self.pg0.remote_hosts[1]
+        if lb and same_pg:
+            server2 = server1
+        if not lb:
+            server = server1
+
+        pg0 = self.pg0
+        if same_pg:
+            pg1 = self.pg0
+        else:
+            pg1 = self.pg1
+
+        eh_translate = ((not self_twice_nat) or (not lb and same_pg) or
+                        client_id == 1)
+
+        self.nat44_add_address(self.nat_addr)
+        self.nat44_add_address(twice_nat_addr, twice_nat=1)
+        if not lb:
+            self.nat44_add_static_mapping(pg0.remote_ip4, self.nat_addr,
+                                          port_in, port_out,
+                                          proto=IP_PROTOS.tcp,
+                                          twice_nat=int(not self_twice_nat),
+                                          self_twice_nat=int(self_twice_nat))
+        else:
+            locals = [{'addr': server1.ip4n,
+                       'port': port_in1,
+                       'probability': 50,
+                       'vrf_id': 0},
+                      {'addr': server2.ip4n,
+                       'port': port_in2,
+                       'probability': 50,
+                       'vrf_id': 0}]
+            out_addr_n = socket.inet_pton(socket.AF_INET, self.nat_addr)
+            self.vapi.nat44_add_del_lb_static_mapping(out_addr_n,
+                                                      port_out,
+                                                      IP_PROTOS.tcp,
+                                                      twice_nat=int(
+                                                          not self_twice_nat),
+                                                      self_twice_nat=int(
+                                                          self_twice_nat),
+                                                      local_num=len(locals),
+                                                      locals=locals)
+        self.vapi.nat44_interface_add_del_feature(pg0.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(pg1.sw_if_index,
                                                   is_inside=0)
 
-        # host to server
-        p = (Ether(dst=self.pg0.local_mac, src=host.mac) /
-             IP(src=host.ip4, dst=server_nat_ip) /
-             GRE() /
-             IP(src=self.pg2.remote_ip4, dst=self.pg3.remote_ip4) /
-             TCP(sport=1234, dport=1234))
-        self.pg0.add_stream(p)
+        if same_pg:
+            if not lb:
+                client = server
+            else:
+                assert client_id is not None
+                if client_id == 1:
+                    client = self.pg0.remote_hosts[0]
+                elif client_id == 2:
+                    client = self.pg0.remote_hosts[1]
+        else:
+            client = pg1.remote_hosts[0]
+        p = (Ether(src=pg1.remote_mac, dst=pg1.local_mac) /
+             IP(src=client.ip4, dst=self.nat_addr) /
+             TCP(sport=eh_port_out, dport=port_out))
+        pg1.add_stream(p)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        p = self.pg0.get_capture(1)
-        packet = p[0]
+        capture = pg0.get_capture(1)
+        p = capture[0]
         try:
-            self.assertEqual(packet[IP].src, host_nat_ip)
-            self.assertEqual(packet[IP].dst, server.ip4)
-            self.assertTrue(packet.haslayer(GRE))
-            self.check_ip_checksum(packet)
+            ip = p[IP]
+            tcp = p[TCP]
+            if lb:
+                if ip.dst == server1.ip4:
+                    server = server1
+                    port_in = port_in1
+                else:
+                    server = server2
+                    port_in = port_in2
+            self.assertEqual(ip.dst, server.ip4)
+            if lb and same_pg:
+                self.assertIn(tcp.dport, [port_in1, port_in2])
+            else:
+                self.assertEqual(tcp.dport, port_in)
+            if eh_translate:
+                self.assertEqual(ip.src, twice_nat_addr)
+                self.assertNotEqual(tcp.sport, eh_port_out)
+            else:
+                self.assertEqual(ip.src, client.ip4)
+                self.assertEqual(tcp.sport, eh_port_out)
+            eh_addr_in = ip.src
+            eh_port_in = tcp.sport
+            saved_port_in = tcp.dport
+            self.assert_packet_checksums_valid(p)
         except:
-            self.logger.error(ppp("Unexpected or invalid packet:", packet))
+            self.logger.error(ppp("Unexpected or invalid packet:", p))
             raise
 
-        # server to host
-        p = (Ether(dst=self.pg0.local_mac, src=server.mac) /
-             IP(src=server.ip4, dst=host_nat_ip) /
-             GRE() /
-             IP(src=self.pg3.remote_ip4, dst=self.pg2.remote_ip4) /
-             TCP(sport=1234, dport=1234))
-        self.pg0.add_stream(p)
+        p = (Ether(src=server.mac, dst=pg0.local_mac) /
+             IP(src=server.ip4, dst=eh_addr_in) /
+             TCP(sport=saved_port_in, dport=eh_port_in))
+        pg0.add_stream(p)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        p = self.pg0.get_capture(1)
-        packet = p[0]
+        capture = pg1.get_capture(1)
+        p = capture[0]
         try:
-            self.assertEqual(packet[IP].src, server_nat_ip)
-            self.assertEqual(packet[IP].dst, host.ip4)
-            self.assertTrue(packet.haslayer(GRE))
-            self.check_ip_checksum(packet)
+            ip = p[IP]
+            tcp = p[TCP]
+            self.assertEqual(ip.dst, client.ip4)
+            self.assertEqual(ip.src, self.nat_addr)
+            self.assertEqual(tcp.dport, eh_port_out)
+            self.assertEqual(tcp.sport, port_out)
+            self.assert_packet_checksums_valid(p)
         except:
-            self.logger.error(ppp("Unexpected or invalid packet:", packet))
+            self.logger.error(ppp("Unexpected or invalid packet:", p))
             raise
 
-    def test_unknown_proto(self):
-        """ NAT44 translate packet with unknown protocol """
-        self.nat44_add_address(self.nat_addr)
+        if eh_translate:
+            sessions = self.vapi.nat44_user_session_dump(server.ip4n, 0)
+            self.assertEqual(len(sessions), 1)
+            self.assertTrue(sessions[0].ext_host_valid)
+            self.assertTrue(sessions[0].is_twicenat)
+            self.vapi.nat44_del_session(
+                sessions[0].inside_ip_address,
+                sessions[0].inside_port,
+                sessions[0].protocol,
+                ext_host_address=sessions[0].ext_host_nat_address,
+                ext_host_port=sessions[0].ext_host_nat_port)
+            sessions = self.vapi.nat44_user_session_dump(server.ip4n, 0)
+            self.assertEqual(len(sessions), 0)
+
+    def test_twice_nat(self):
+        """ Twice NAT44 """
+        self.twice_nat_common()
+
+    def test_self_twice_nat_positive(self):
+        """ Self Twice NAT44 (positive test) """
+        self.twice_nat_common(self_twice_nat=True, same_pg=True)
+
+    def test_self_twice_nat_negative(self):
+        """ Self Twice NAT44 (negative test) """
+        self.twice_nat_common(self_twice_nat=True)
+
+    def test_twice_nat_lb(self):
+        """ Twice NAT44 local service load balancing """
+        self.twice_nat_common(lb=True)
+
+    def test_self_twice_nat_lb_positive(self):
+        """ Self Twice NAT44 local service load balancing (positive test) """
+        self.twice_nat_common(lb=True, self_twice_nat=True, same_pg=True,
+                              client_id=1)
+
+    def test_self_twice_nat_lb_negative(self):
+        """ Self Twice NAT44 local service load balancing (negative test) """
+        self.twice_nat_common(lb=True, self_twice_nat=True, same_pg=True,
+                              client_id=2)
+
+    def test_twice_nat_interface_addr(self):
+        """ Acquire twice NAT44 addresses from interface """
+        self.vapi.nat44_add_interface_addr(self.pg3.sw_if_index, twice_nat=1)
+
+        # no address in NAT pool
+        adresses = self.vapi.nat44_address_dump()
+        self.assertEqual(0, len(adresses))
+
+        # configure interface address and check NAT address pool
+        self.pg3.config_ip4()
+        adresses = self.vapi.nat44_address_dump()
+        self.assertEqual(1, len(adresses))
+        self.assertEqual(adresses[0].ip_address[0:4], self.pg3.local_ip4n)
+        self.assertEqual(adresses[0].twice_nat, 1)
+
+        # remove interface address and check NAT address pool
+        self.pg3.unconfig_ip4()
+        adresses = self.vapi.nat44_address_dump()
+        self.assertEqual(0, len(adresses))
+
+    def test_tcp_close(self):
+        """ Close TCP session from inside network - output feature """
+        self.vapi.nat44_forwarding_enable_disable(1)
+        self.nat44_add_address(self.pg1.local_ip4)
+        twice_nat_addr = '10.0.1.3'
+        service_ip = '192.168.16.150'
+        self.nat44_add_address(twice_nat_addr, twice_nat=1)
         self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
-        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
+        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index,
                                                   is_inside=0)
+        self.vapi.nat44_interface_add_del_output_feature(self.pg1.sw_if_index,
+                                                         is_inside=0)
+        self.nat44_add_static_mapping(self.pg0.remote_ip4,
+                                      service_ip,
+                                      80,
+                                      80,
+                                      proto=IP_PROTOS.tcp,
+                                      out2in_only=1,
+                                      twice_nat=1)
+        sessions = self.vapi.nat44_user_session_dump(self.pg0.remote_ip4n, 0)
+        start_sessnum = len(sessions)
 
-        # in2out
-        p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
-             IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4) /
-             TCP(sport=self.tcp_port_in, dport=20))
-        self.pg0.add_stream(p)
+        # SYN packet out->in
+        p = (Ether(src=self.pg1.remote_mac, dst=self.pg1.local_mac) /
+             IP(src=self.pg1.remote_ip4, dst=service_ip) /
+             TCP(sport=33898, dport=80, flags="S"))
+        self.pg1.add_stream(p)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        p = self.pg1.get_capture(1)
+        capture = self.pg0.get_capture(1)
+        p = capture[0]
+        tcp_port = p[TCP].sport
 
-        p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
-             IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4) /
-             GRE() /
-             IP(src=self.pg2.remote_ip4, dst=self.pg3.remote_ip4) /
-             TCP(sport=1234, dport=1234))
+        # SYN + ACK packet in->out
+        p = (Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac) /
+             IP(src=self.pg0.remote_ip4, dst=twice_nat_addr) /
+             TCP(sport=80, dport=tcp_port, flags="SA"))
         self.pg0.add_stream(p)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        p = self.pg1.get_capture(1)
-        packet = p[0]
-        try:
-            self.assertEqual(packet[IP].src, self.nat_addr)
-            self.assertEqual(packet[IP].dst, self.pg1.remote_ip4)
-            self.assertTrue(packet.haslayer(GRE))
-            self.check_ip_checksum(packet)
-        except:
-            self.logger.error(ppp("Unexpected or invalid packet:", packet))
-            raise
+        self.pg1.get_capture(1)
 
-        # out2in
-        p = (Ether(dst=self.pg1.local_mac, src=self.pg1.remote_mac) /
-             IP(src=self.pg1.remote_ip4, dst=self.nat_addr) /
-             GRE() /
-             IP(src=self.pg3.remote_ip4, dst=self.pg2.remote_ip4) /
-             TCP(sport=1234, dport=1234))
+        # ACK packet out->in
+        p = (Ether(src=self.pg1.remote_mac, dst=self.pg1.local_mac) /
+             IP(src=self.pg1.remote_ip4, dst=service_ip) /
+             TCP(sport=33898, dport=80, flags="A"))
         self.pg1.add_stream(p)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        p = self.pg0.get_capture(1)
-        packet = p[0]
-        try:
-            self.assertEqual(packet[IP].src, self.pg1.remote_ip4)
-            self.assertEqual(packet[IP].dst, self.pg0.remote_ip4)
-            self.assertTrue(packet.haslayer(GRE))
-            self.check_ip_checksum(packet)
-        except:
-            self.logger.error(ppp("Unexpected or invalid packet:", packet))
-            raise
-
-    def test_hairpinning_unknown_proto(self):
-        """ NAT44 translate packet with unknown protocol - hairpinning """
-        host = self.pg0.remote_hosts[0]
-        server = self.pg0.remote_hosts[1]
-        host_in_port = 1234
-        host_out_port = 0
-        server_in_port = 5678
-        server_out_port = 8765
-        server_nat_ip = "10.0.0.11"
-
-        self.nat44_add_address(self.nat_addr)
-        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
-        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
-                                                  is_inside=0)
+        self.pg0.get_capture(1)
 
-        # add static mapping for server
-        self.nat44_add_static_mapping(server.ip4, server_nat_ip)
-
-        # host to server
-        p = (Ether(src=host.mac, dst=self.pg0.local_mac) /
-             IP(src=host.ip4, dst=server_nat_ip) /
-             TCP(sport=host_in_port, dport=server_out_port))
+        # FIN packet in -> out
+        p = (Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac) /
+             IP(src=self.pg0.remote_ip4, dst=twice_nat_addr) /
+             TCP(sport=80, dport=tcp_port, flags="FA", seq=100, ack=300))
         self.pg0.add_stream(p)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        capture = self.pg0.get_capture(1)
+        self.pg1.get_capture(1)
 
-        p = (Ether(dst=self.pg0.local_mac, src=host.mac) /
-             IP(src=host.ip4, dst=server_nat_ip) /
-             GRE() /
-             IP(src=self.pg2.remote_ip4, dst=self.pg3.remote_ip4) /
-             TCP(sport=1234, dport=1234))
-        self.pg0.add_stream(p)
+        # FIN+ACK packet out -> in
+        p = (Ether(src=self.pg1.remote_mac, dst=self.pg1.local_mac) /
+             IP(src=self.pg1.remote_ip4, dst=service_ip) /
+             TCP(sport=33898, dport=80, flags="FA", seq=300, ack=101))
+        self.pg1.add_stream(p)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        p = self.pg0.get_capture(1)
-        packet = p[0]
-        try:
-            self.assertEqual(packet[IP].src, self.nat_addr)
-            self.assertEqual(packet[IP].dst, server.ip4)
-            self.assertTrue(packet.haslayer(GRE))
-            self.check_ip_checksum(packet)
-        except:
-            self.logger.error(ppp("Unexpected or invalid packet:", packet))
-            raise
+        self.pg0.get_capture(1)
 
-        # server to host
-        p = (Ether(dst=self.pg0.local_mac, src=server.mac) /
-             IP(src=server.ip4, dst=self.nat_addr) /
-             GRE() /
-             IP(src=self.pg3.remote_ip4, dst=self.pg2.remote_ip4) /
-             TCP(sport=1234, dport=1234))
+        # ACK packet in -> out
+        p = (Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac) /
+             IP(src=self.pg0.remote_ip4, dst=twice_nat_addr) /
+             TCP(sport=80, dport=tcp_port, flags="A", seq=101, ack=301))
         self.pg0.add_stream(p)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        p = self.pg0.get_capture(1)
-        packet = p[0]
-        try:
-            self.assertEqual(packet[IP].src, server_nat_ip)
-            self.assertEqual(packet[IP].dst, host.ip4)
-            self.assertTrue(packet.haslayer(GRE))
-            self.check_ip_checksum(packet)
-        except:
-            self.logger.error(ppp("Unexpected or invalid packet:", packet))
-            raise
+        self.pg1.get_capture(1)
 
-    def test_output_feature(self):
-        """ NAT44 interface output feature (in2out postrouting) """
+        sessions = self.vapi.nat44_user_session_dump(self.pg0.remote_ip4n,
+                                                     0)
+        self.assertEqual(len(sessions) - start_sessnum, 0)
+
+    def test_tcp_session_close_in(self):
+        """ Close TCP session from inside network """
+        self.tcp_port_out = 10505
         self.nat44_add_address(self.nat_addr)
-        self.vapi.nat44_interface_add_del_output_feature(self.pg0.sw_if_index)
-        self.vapi.nat44_interface_add_del_output_feature(self.pg1.sw_if_index)
-        self.vapi.nat44_interface_add_del_output_feature(self.pg3.sw_if_index,
-                                                         is_inside=0)
+        self.nat44_add_static_mapping(self.pg0.remote_ip4,
+                                      self.nat_addr,
+                                      self.tcp_port_in,
+                                      self.tcp_port_out,
+                                      proto=IP_PROTOS.tcp,
+                                      twice_nat=1)
+        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
+                                                  is_inside=0)
 
-        # in2out
-        pkts = self.create_stream_in(self.pg0, self.pg3)
-        self.pg0.add_stream(pkts)
+        sessions = self.vapi.nat44_user_session_dump(self.pg0.remote_ip4n, 0)
+        start_sessnum = len(sessions)
+
+        self.initiate_tcp_session(self.pg0, self.pg1)
+
+        # FIN packet in -> out
+        p = (Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac) /
+             IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4) /
+             TCP(sport=self.tcp_port_in, dport=self.tcp_external_port,
+                 flags="FA", seq=100, ack=300))
+        self.pg0.add_stream(p)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        capture = self.pg3.get_capture(len(pkts))
-        self.verify_capture_out(capture)
+        self.pg1.get_capture(1)
 
-        # out2in
-        pkts = self.create_stream_out(self.pg3)
-        self.pg3.add_stream(pkts)
+        pkts = []
+
+        # ACK packet out -> in
+        p = (Ether(src=self.pg1.remote_mac, dst=self.pg1.local_mac) /
+             IP(src=self.pg1.remote_ip4, dst=self.nat_addr) /
+             TCP(sport=self.tcp_external_port, dport=self.tcp_port_out,
+                 flags="A", seq=300, ack=101))
+        pkts.append(p)
+
+        # FIN packet out -> in
+        p = (Ether(src=self.pg1.remote_mac, dst=self.pg1.local_mac) /
+             IP(src=self.pg1.remote_ip4, dst=self.nat_addr) /
+             TCP(sport=self.tcp_external_port, dport=self.tcp_port_out,
+                 flags="FA", seq=300, ack=101))
+        pkts.append(p)
+
+        self.pg1.add_stream(pkts)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        capture = self.pg0.get_capture(len(pkts))
-        self.verify_capture_in(capture, self.pg0)
+        self.pg0.get_capture(2)
 
-        # from non-NAT interface to NAT inside interface
-        pkts = self.create_stream_in(self.pg2, self.pg0)
-        self.pg2.add_stream(pkts)
+        # ACK packet in -> out
+        p = (Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac) /
+             IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4) /
+             TCP(sport=self.tcp_port_in, dport=self.tcp_external_port,
+                 flags="A", seq=101, ack=301))
+        self.pg0.add_stream(p)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        capture = self.pg0.get_capture(len(pkts))
-        self.verify_capture_no_translation(capture, self.pg2, self.pg0)
+        self.pg1.get_capture(1)
 
-    def test_output_feature_vrf_aware(self):
-        """ NAT44 interface output feature VRF aware (in2out postrouting) """
-        nat_ip_vrf10 = "10.0.0.10"
-        nat_ip_vrf20 = "10.0.0.20"
+        sessions = self.vapi.nat44_user_session_dump(self.pg0.remote_ip4n,
+                                                     0)
+        self.assertEqual(len(sessions) - start_sessnum, 0)
 
-        self.vapi.ip_add_del_route(dst_address=self.pg3.remote_ip4n,
-                                   dst_address_length=32,
-                                   next_hop_address=self.pg3.remote_ip4n,
-                                   next_hop_sw_if_index=self.pg3.sw_if_index,
-                                   table_id=10)
-        self.vapi.ip_add_del_route(dst_address=self.pg3.remote_ip4n,
-                                   dst_address_length=32,
-                                   next_hop_address=self.pg3.remote_ip4n,
-                                   next_hop_sw_if_index=self.pg3.sw_if_index,
-                                   table_id=20)
+    def test_tcp_session_close_out(self):
+        """ Close TCP session from outside network """
+        self.tcp_port_out = 10505
+        self.nat44_add_address(self.nat_addr)
+        self.nat44_add_static_mapping(self.pg0.remote_ip4,
+                                      self.nat_addr,
+                                      self.tcp_port_in,
+                                      self.tcp_port_out,
+                                      proto=IP_PROTOS.tcp,
+                                      twice_nat=1)
+        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
+                                                  is_inside=0)
 
-        self.nat44_add_address(nat_ip_vrf10, vrf_id=10)
-        self.nat44_add_address(nat_ip_vrf20, vrf_id=20)
-        self.vapi.nat44_interface_add_del_output_feature(self.pg4.sw_if_index)
-        self.vapi.nat44_interface_add_del_output_feature(self.pg6.sw_if_index)
-        self.vapi.nat44_interface_add_del_output_feature(self.pg3.sw_if_index,
-                                                         is_inside=0)
+        sessions = self.vapi.nat44_user_session_dump(self.pg0.remote_ip4n, 0)
+        start_sessnum = len(sessions)
 
-        # in2out VRF 10
-        pkts = self.create_stream_in(self.pg4, self.pg3)
-        self.pg4.add_stream(pkts)
-        self.pg_enable_capture(self.pg_interfaces)
-        self.pg_start()
-        capture = self.pg3.get_capture(len(pkts))
-        self.verify_capture_out(capture, nat_ip=nat_ip_vrf10)
+        self.initiate_tcp_session(self.pg0, self.pg1)
 
-        # out2in VRF 10
-        pkts = self.create_stream_out(self.pg3, dst_ip=nat_ip_vrf10)
-        self.pg3.add_stream(pkts)
+        # FIN packet out -> in
+        p = (Ether(src=self.pg1.remote_mac, dst=self.pg1.local_mac) /
+             IP(src=self.pg1.remote_ip4, dst=self.nat_addr) /
+             TCP(sport=self.tcp_external_port, dport=self.tcp_port_out,
+                 flags="FA", seq=100, ack=300))
+        self.pg1.add_stream(p)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        capture = self.pg4.get_capture(len(pkts))
-        self.verify_capture_in(capture, self.pg4)
+        self.pg0.get_capture(1)
+
+        # FIN+ACK packet in -> out
+        p = (Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac) /
+             IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4) /
+             TCP(sport=self.tcp_port_in, dport=self.tcp_external_port,
+                 flags="FA", seq=300, ack=101))
 
-        # in2out VRF 20
-        pkts = self.create_stream_in(self.pg6, self.pg3)
-        self.pg6.add_stream(pkts)
+        self.pg0.add_stream(p)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        capture = self.pg3.get_capture(len(pkts))
-        self.verify_capture_out(capture, nat_ip=nat_ip_vrf20)
+        self.pg1.get_capture(1)
 
-        # out2in VRF 20
-        pkts = self.create_stream_out(self.pg3, dst_ip=nat_ip_vrf20)
-        self.pg3.add_stream(pkts)
+        # ACK packet out -> in
+        p = (Ether(src=self.pg1.remote_mac, dst=self.pg1.local_mac) /
+             IP(src=self.pg1.remote_ip4, dst=self.nat_addr) /
+             TCP(sport=self.tcp_external_port, dport=self.tcp_port_out,
+                 flags="A", seq=101, ack=301))
+        self.pg1.add_stream(p)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        capture = self.pg6.get_capture(len(pkts))
-        self.verify_capture_in(capture, self.pg6)
+        self.pg0.get_capture(1)
 
-    def test_output_feature_hairpinning(self):
-        """ NAT44 interface output feature hairpinning (in2out postrouting) """
-        host = self.pg0.remote_hosts[0]
-        server = self.pg0.remote_hosts[1]
-        host_in_port = 1234
-        host_out_port = 0
-        server_in_port = 5678
-        server_out_port = 8765
+        sessions = self.vapi.nat44_user_session_dump(self.pg0.remote_ip4n,
+                                                     0)
+        self.assertEqual(len(sessions) - start_sessnum, 0)
 
+    def test_tcp_session_close_simultaneous(self):
+        """ Close TCP session from inside network """
+        self.tcp_port_out = 10505
         self.nat44_add_address(self.nat_addr)
-        self.vapi.nat44_interface_add_del_output_feature(self.pg0.sw_if_index)
-        self.vapi.nat44_interface_add_del_output_feature(self.pg1.sw_if_index,
-                                                         is_inside=0)
+        self.nat44_add_static_mapping(self.pg0.remote_ip4,
+                                      self.nat_addr,
+                                      self.tcp_port_in,
+                                      self.tcp_port_out,
+                                      proto=IP_PROTOS.tcp,
+                                      twice_nat=1)
+        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
+                                                  is_inside=0)
 
-        # add static mapping for server
-        self.nat44_add_static_mapping(server.ip4, self.nat_addr,
-                                      server_in_port, server_out_port,
-                                      proto=IP_PROTOS.tcp)
+        sessions = self.vapi.nat44_user_session_dump(self.pg0.remote_ip4n, 0)
+        start_sessnum = len(sessions)
 
-        # send packet from host to server
-        p = (Ether(src=host.mac, dst=self.pg0.local_mac) /
-             IP(src=host.ip4, dst=self.nat_addr) /
-             TCP(sport=host_in_port, dport=server_out_port))
+        self.initiate_tcp_session(self.pg0, self.pg1)
+
+        # FIN packet in -> out
+        p = (Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac) /
+             IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4) /
+             TCP(sport=self.tcp_port_in, dport=self.tcp_external_port,
+                 flags="FA", seq=100, ack=300))
         self.pg0.add_stream(p)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        capture = self.pg0.get_capture(1)
-        p = capture[0]
-        try:
-            ip = p[IP]
-            tcp = p[TCP]
-            self.assertEqual(ip.src, self.nat_addr)
-            self.assertEqual(ip.dst, server.ip4)
-            self.assertNotEqual(tcp.sport, host_in_port)
-            self.assertEqual(tcp.dport, server_in_port)
-            self.check_tcp_checksum(p)
-            host_out_port = tcp.sport
-        except:
-            self.logger.error(ppp("Unexpected or invalid packet:", p))
-            raise
+        self.pg1.get_capture(1)
 
-        # send reply from server to host
-        p = (Ether(src=server.mac, dst=self.pg0.local_mac) /
-             IP(src=server.ip4, dst=self.nat_addr) /
-             TCP(sport=server_in_port, dport=host_out_port))
+        # FIN packet out -> in
+        p = (Ether(src=self.pg1.remote_mac, dst=self.pg1.local_mac) /
+             IP(src=self.pg1.remote_ip4, dst=self.nat_addr) /
+             TCP(sport=self.tcp_external_port, dport=self.tcp_port_out,
+                 flags="FA", seq=300, ack=100))
+        self.pg1.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        self.pg0.get_capture(1)
+
+        # ACK packet in -> out
+        p = (Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac) /
+             IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4) /
+             TCP(sport=self.tcp_port_in, dport=self.tcp_external_port,
+                 flags="A", seq=101, ack=301))
         self.pg0.add_stream(p)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        capture = self.pg0.get_capture(1)
-        p = capture[0]
-        try:
-            ip = p[IP]
-            tcp = p[TCP]
-            self.assertEqual(ip.src, self.nat_addr)
-            self.assertEqual(ip.dst, host.ip4)
-            self.assertEqual(tcp.sport, server_out_port)
-            self.assertEqual(tcp.dport, host_in_port)
-            self.check_tcp_checksum(p)
-        except:
-            self.logger.error(ppp("Unexpected or invalid packet:", p))
-            raise
+        self.pg1.get_capture(1)
 
-    def test_output_feature_and_service(self):
-        """ NAT44 interface output feature and services """
-        external_addr = '1.2.3.4'
+        # ACK packet out -> in
+        p = (Ether(src=self.pg1.remote_mac, dst=self.pg1.local_mac) /
+             IP(src=self.pg1.remote_ip4, dst=self.nat_addr) /
+             TCP(sport=self.tcp_external_port, dport=self.tcp_port_out,
+                 flags="A", seq=301, ack=101))
+        self.pg1.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        self.pg0.get_capture(1)
+
+        sessions = self.vapi.nat44_user_session_dump(self.pg0.remote_ip4n,
+                                                     0)
+        self.assertEqual(len(sessions) - start_sessnum, 0)
+
+    def test_one_armed_nat44_static(self):
+        """ One armed NAT44 and 1:1 NAPT asymmetrical rule """
+        remote_host = self.pg4.remote_hosts[0]
+        local_host = self.pg4.remote_hosts[1]
         external_port = 80
         local_port = 8080
+        eh_port_in = 0
 
         self.vapi.nat44_forwarding_enable_disable(1)
-        self.nat44_add_address(self.nat_addr)
-        self.nat44_add_static_mapping(self.pg0.remote_ip4, external_addr,
+        self.nat44_add_address(self.nat_addr, twice_nat=1)
+        self.nat44_add_static_mapping(local_host.ip4, self.nat_addr,
                                       local_port, external_port,
-                                      proto=IP_PROTOS.tcp, out2in_only=1)
-        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
-        self.vapi.nat44_interface_add_del_output_feature(self.pg1.sw_if_index,
-                                                         is_inside=0)
+                                      proto=IP_PROTOS.tcp, out2in_only=1,
+                                      twice_nat=1)
+        self.vapi.nat44_interface_add_del_feature(self.pg4.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg4.sw_if_index,
+                                                  is_inside=0)
 
         # from client to service
-        p = (Ether(src=self.pg1.remote_mac, dst=self.pg1.local_mac) /
-             IP(src=self.pg1.remote_ip4, dst=external_addr) /
+        p = (Ether(src=self.pg4.remote_mac, dst=self.pg4.local_mac) /
+             IP(src=remote_host.ip4, dst=self.nat_addr) /
              TCP(sport=12345, dport=external_port))
-        self.pg1.add_stream(p)
+        self.pg4.add_stream(p)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        capture = self.pg0.get_capture(1)
+        capture = self.pg4.get_capture(1)
         p = capture[0]
-        server = None
         try:
             ip = p[IP]
             tcp = p[TCP]
-            self.assertEqual(ip.dst, self.pg0.remote_ip4)
+            self.assertEqual(ip.dst, local_host.ip4)
+            self.assertEqual(ip.src, self.nat_addr)
             self.assertEqual(tcp.dport, local_port)
-            self.check_tcp_checksum(p)
-            self.check_ip_checksum(p)
+            self.assertNotEqual(tcp.sport, 12345)
+            eh_port_in = tcp.sport
+            self.assert_packet_checksums_valid(p)
         except:
             self.logger.error(ppp("Unexpected or invalid packet:", p))
             raise
 
         # from service back to client
-        p = (Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac) /
-             IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4) /
-             TCP(sport=local_port, dport=12345))
-        self.pg0.add_stream(p)
+        p = (Ether(src=self.pg4.remote_mac, dst=self.pg4.local_mac) /
+             IP(src=local_host.ip4, dst=self.nat_addr) /
+             TCP(sport=local_port, dport=eh_port_in))
+        self.pg4.add_stream(p)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        capture = self.pg1.get_capture(1)
+        capture = self.pg4.get_capture(1)
         p = capture[0]
         try:
             ip = p[IP]
             tcp = p[TCP]
-            self.assertEqual(ip.src, external_addr)
+            self.assertEqual(ip.src, self.nat_addr)
+            self.assertEqual(ip.dst, remote_host.ip4)
             self.assertEqual(tcp.sport, external_port)
-            self.check_tcp_checksum(p)
-            self.check_ip_checksum(p)
+            self.assertEqual(tcp.dport, 12345)
+            self.assert_packet_checksums_valid(p)
         except:
             self.logger.error(ppp("Unexpected or invalid packet:", p))
             raise
 
-        # from local network host to external network
-        pkts = self.create_stream_in(self.pg0, self.pg1)
-        self.pg0.add_stream(pkts)
-        self.pg_enable_capture(self.pg_interfaces)
-        self.pg_start()
-        capture = self.pg1.get_capture(len(pkts))
-        self.verify_capture_out(capture)
-        pkts = self.create_stream_in(self.pg0, self.pg1)
-        self.pg0.add_stream(pkts)
-        self.pg_enable_capture(self.pg_interfaces)
-        self.pg_start()
-        capture = self.pg1.get_capture(len(pkts))
-        self.verify_capture_out(capture)
-
-        # from external network back to local network host
-        pkts = self.create_stream_out(self.pg1)
-        self.pg1.add_stream(pkts)
-        self.pg_enable_capture(self.pg_interfaces)
-        self.pg_start()
-        capture = self.pg0.get_capture(len(pkts))
-        self.verify_capture_in(capture, self.pg0)
-
-    def test_output_feature_and_service2(self):
-        """ NAT44 interface output feature and service host direct access """
-        self.vapi.nat44_forwarding_enable_disable(1)
-        self.nat44_add_address(self.nat_addr)
-        self.vapi.nat44_interface_add_del_output_feature(self.pg1.sw_if_index,
-                                                         is_inside=0)
-
-        # session initiaded from service host - translate
-        pkts = self.create_stream_in(self.pg0, self.pg1)
-        self.pg0.add_stream(pkts)
-        self.pg_enable_capture(self.pg_interfaces)
-        self.pg_start()
-        capture = self.pg1.get_capture(len(pkts))
-        self.verify_capture_out(capture)
-
-        pkts = self.create_stream_out(self.pg1)
-        self.pg1.add_stream(pkts)
-        self.pg_enable_capture(self.pg_interfaces)
-        self.pg_start()
-        capture = self.pg0.get_capture(len(pkts))
-        self.verify_capture_in(capture, self.pg0)
-
-        tcp_port_out = self.tcp_port_out
-        udp_port_out = self.udp_port_out
-        icmp_id_out = self.icmp_id_out
-
-        # session initiaded from remote host - do not translate
-        pkts = self.create_stream_out(self.pg1,
-                                      self.pg0.remote_ip4,
-                                      use_inside_ports=True)
-        self.pg1.add_stream(pkts)
-        self.pg_enable_capture(self.pg_interfaces)
-        self.pg_start()
-        capture = self.pg0.get_capture(len(pkts))
-        self.verify_capture_in(capture, self.pg0)
-
-        pkts = self.create_stream_in(self.pg0, self.pg1)
-        self.pg0.add_stream(pkts)
-        self.pg_enable_capture(self.pg_interfaces)
-        self.pg_start()
-        capture = self.pg1.get_capture(len(pkts))
-        self.verify_capture_out(capture, nat_ip=self.pg0.remote_ip4,
-                                same_port=True)
+    def test_static_with_port_out2(self):
+        """ 1:1 NAPT asymmetrical rule """
 
-    def test_output_feature_and_service3(self):
-        """ NAT44 interface output feature and DST NAT """
-        external_addr = '1.2.3.4'
         external_port = 80
         local_port = 8080
 
         self.vapi.nat44_forwarding_enable_disable(1)
-        self.nat44_add_address(self.nat_addr)
-        self.nat44_add_static_mapping(self.pg1.remote_ip4, external_addr,
+        self.nat44_add_static_mapping(self.pg0.remote_ip4, self.nat_addr,
                                       local_port, external_port,
                                       proto=IP_PROTOS.tcp, out2in_only=1)
         self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
-        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index,
+        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
                                                   is_inside=0)
-        self.vapi.nat44_interface_add_del_output_feature(self.pg1.sw_if_index,
-                                                         is_inside=0)
 
-        p = (Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac) /
-             IP(src=self.pg0.remote_ip4, dst=external_addr) /
+        # from client to service
+        p = (Ether(src=self.pg1.remote_mac, dst=self.pg1.local_mac) /
+             IP(src=self.pg1.remote_ip4, dst=self.nat_addr) /
              TCP(sport=12345, dport=external_port))
-        self.pg0.add_stream(p)
+        self.pg1.add_stream(p)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        capture = self.pg1.get_capture(1)
+        capture = self.pg0.get_capture(1)
         p = capture[0]
         try:
             ip = p[IP]
             tcp = p[TCP]
-            self.assertEqual(ip.src, self.pg0.remote_ip4)
-            self.assertEqual(tcp.sport, 12345)
-            self.assertEqual(ip.dst, self.pg1.remote_ip4)
+            self.assertEqual(ip.dst, self.pg0.remote_ip4)
             self.assertEqual(tcp.dport, local_port)
-            self.check_tcp_checksum(p)
-            self.check_ip_checksum(p)
+            self.assert_packet_checksums_valid(p)
         except:
             self.logger.error(ppp("Unexpected or invalid packet:", p))
             raise
 
-        p = (Ether(src=self.pg1.remote_mac, dst=self.pg1.local_mac) /
-             IP(src=self.pg1.remote_ip4, dst=self.pg0.remote_ip4) /
-             TCP(sport=local_port, dport=12345))
-        self.pg1.add_stream(p)
+        # ICMP error
+        p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
+             IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4) /
+             ICMP(type=11) / capture[0][IP])
+        self.pg0.add_stream(p)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        capture = self.pg0.get_capture(1)
+        capture = self.pg1.get_capture(1)
         p = capture[0]
         try:
-            ip = p[IP]
-            tcp = p[TCP]
-            self.assertEqual(ip.src, external_addr)
-            self.assertEqual(tcp.sport, external_port)
-            self.assertEqual(ip.dst, self.pg0.remote_ip4)
-            self.assertEqual(tcp.dport, 12345)
-            self.check_tcp_checksum(p)
-            self.check_ip_checksum(p)
+            self.assertEqual(p[IP].src, self.nat_addr)
+            inner = p[IPerror]
+            self.assertEqual(inner.dst, self.nat_addr)
+            self.assertEqual(inner[TCPerror].dport, external_port)
         except:
             self.logger.error(ppp("Unexpected or invalid packet:", p))
             raise
 
-    def test_one_armed_nat44(self):
-        """ One armed NAT44 """
-        remote_host = self.pg9.remote_hosts[0]
-        local_host = self.pg9.remote_hosts[1]
-        external_port = 0
-
-        self.nat44_add_address(self.nat_addr)
-        self.vapi.nat44_interface_add_del_feature(self.pg9.sw_if_index)
-        self.vapi.nat44_interface_add_del_feature(self.pg9.sw_if_index,
-                                                  is_inside=0)
-
-        # in2out
-        p = (Ether(src=self.pg9.remote_mac, dst=self.pg9.local_mac) /
-             IP(src=local_host.ip4, dst=remote_host.ip4) /
-             TCP(sport=12345, dport=80))
-        self.pg9.add_stream(p)
+        # from service back to client
+        p = (Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac) /
+             IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4) /
+             TCP(sport=local_port, dport=12345))
+        self.pg0.add_stream(p)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        capture = self.pg9.get_capture(1)
+        capture = self.pg1.get_capture(1)
         p = capture[0]
         try:
             ip = p[IP]
             tcp = p[TCP]
             self.assertEqual(ip.src, self.nat_addr)
-            self.assertEqual(ip.dst, remote_host.ip4)
-            self.assertNotEqual(tcp.sport, 12345)
-            external_port = tcp.sport
-            self.assertEqual(tcp.dport, 80)
-            self.check_tcp_checksum(p)
-            self.check_ip_checksum(p)
+            self.assertEqual(tcp.sport, external_port)
+            self.assert_packet_checksums_valid(p)
         except:
             self.logger.error(ppp("Unexpected or invalid packet:", p))
             raise
 
-        # out2in
-        p = (Ether(src=self.pg9.remote_mac, dst=self.pg9.local_mac) /
-             IP(src=remote_host.ip4, dst=self.nat_addr) /
-             TCP(sport=80, dport=external_port))
-        self.pg9.add_stream(p)
+        # ICMP error
+        p = (Ether(dst=self.pg1.local_mac, src=self.pg1.remote_mac) /
+             IP(src=self.pg1.remote_ip4, dst=self.nat_addr) /
+             ICMP(type=11) / capture[0][IP])
+        self.pg1.add_stream(p)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        capture = self.pg9.get_capture(1)
+        capture = self.pg0.get_capture(1)
         p = capture[0]
         try:
-            ip = p[IP]
-            tcp = p[TCP]
-            self.assertEqual(ip.src, remote_host.ip4)
-            self.assertEqual(ip.dst, local_host.ip4)
-            self.assertEqual(tcp.sport, 80)
-            self.assertEqual(tcp.dport, 12345)
-            self.check_tcp_checksum(p)
-            self.check_ip_checksum(p)
+            self.assertEqual(p[IP].dst, self.pg0.remote_ip4)
+            inner = p[IPerror]
+            self.assertEqual(inner.src, self.pg0.remote_ip4)
+            self.assertEqual(inner[TCPerror].sport, local_port)
         except:
             self.logger.error(ppp("Unexpected or invalid packet:", p))
             raise
 
-    def test_one_armed_nat44_static(self):
-        """ One armed NAT44 and 1:1 NAPT symmetrical rule """
-        remote_host = self.pg9.remote_hosts[0]
-        local_host = self.pg9.remote_hosts[1]
-        external_port = 80
-        local_port = 8080
-        eh_port_in = 0
-
-        self.vapi.nat44_forwarding_enable_disable(1)
-        self.nat44_add_address(self.nat_addr, twice_nat=1)
-        self.nat44_add_static_mapping(local_host.ip4, self.nat_addr,
-                                      local_port, external_port,
-                                      proto=IP_PROTOS.tcp, out2in_only=1,
-                                      twice_nat=1)
-        self.vapi.nat44_interface_add_del_feature(self.pg9.sw_if_index)
-        self.vapi.nat44_interface_add_del_feature(self.pg9.sw_if_index,
-                                                  is_inside=0)
-
-        # from client to service
-        p = (Ether(src=self.pg9.remote_mac, dst=self.pg9.local_mac) /
-             IP(src=remote_host.ip4, dst=self.nat_addr) /
-             TCP(sport=12345, dport=external_port))
-        self.pg9.add_stream(p)
+        # from client to server (no translation)
+        p = (Ether(src=self.pg1.remote_mac, dst=self.pg1.local_mac) /
+             IP(src=self.pg1.remote_ip4, dst=self.pg0.remote_ip4) /
+             TCP(sport=12346, dport=local_port))
+        self.pg1.add_stream(p)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        capture = self.pg9.get_capture(1)
+        capture = self.pg0.get_capture(1)
         p = capture[0]
-        server = None
         try:
             ip = p[IP]
             tcp = p[TCP]
-            self.assertEqual(ip.dst, local_host.ip4)
-            self.assertEqual(ip.src, self.nat_addr)
+            self.assertEqual(ip.dst, self.pg0.remote_ip4)
             self.assertEqual(tcp.dport, local_port)
-            self.assertNotEqual(tcp.sport, 12345)
-            eh_port_in = tcp.sport
-            self.check_tcp_checksum(p)
-            self.check_ip_checksum(p)
+            self.assert_packet_checksums_valid(p)
         except:
             self.logger.error(ppp("Unexpected or invalid packet:", p))
             raise
 
-        # from service back to client
-        p = (Ether(src=self.pg9.remote_mac, dst=self.pg9.local_mac) /
-             IP(src=local_host.ip4, dst=self.nat_addr) /
-             TCP(sport=local_port, dport=eh_port_in))
-        self.pg9.add_stream(p)
+        # from service back to client (no translation)
+        p = (Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac) /
+             IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4) /
+             TCP(sport=local_port, dport=12346))
+        self.pg0.add_stream(p)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        capture = self.pg9.get_capture(1)
+        capture = self.pg1.get_capture(1)
         p = capture[0]
         try:
             ip = p[IP]
             tcp = p[TCP]
-            self.assertEqual(ip.src, self.nat_addr)
-            self.assertEqual(ip.dst, remote_host.ip4)
-            self.assertEqual(tcp.sport, external_port)
-            self.assertEqual(tcp.dport, 12345)
-            self.check_tcp_checksum(p)
-            self.check_ip_checksum(p)
+            self.assertEqual(ip.src, self.pg0.remote_ip4)
+            self.assertEqual(tcp.sport, local_port)
+            self.assert_packet_checksums_valid(p)
         except:
             self.logger.error(ppp("Unexpected or invalid packet:", p))
             raise
 
-    def test_del_session(self):
-        """ Delete NAT44 session """
+    def test_output_feature(self):
+        """ NAT44 interface output feature (in2out postrouting) """
+        self.vapi.nat44_forwarding_enable_disable(1)
         self.nat44_add_address(self.nat_addr)
-        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
-        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
+        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index,
                                                   is_inside=0)
+        self.vapi.nat44_interface_add_del_output_feature(self.pg1.sw_if_index,
+                                                         is_inside=0)
 
+        # in2out
         pkts = self.create_stream_in(self.pg0, self.pg1)
         self.pg0.add_stream(pkts)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
         capture = self.pg1.get_capture(len(pkts))
-
-        sessions = self.vapi.nat44_user_session_dump(self.pg0.remote_ip4n, 0)
-        nsessions = len(sessions)
-
-        self.vapi.nat44_del_session(sessions[0].inside_ip_address,
-                                    sessions[0].inside_port,
-                                    sessions[0].protocol)
-        self.vapi.nat44_del_session(sessions[1].outside_ip_address,
-                                    sessions[1].outside_port,
-                                    sessions[1].protocol,
-                                    is_in=0)
-
-        sessions = self.vapi.nat44_user_session_dump(self.pg0.remote_ip4n, 0)
-        self.assertEqual(nsessions - len(sessions), 2)
-
-    def test_set_get_reass(self):
-        """ NAT44 set/get virtual fragmentation reassembly """
-        reas_cfg1 = self.vapi.nat_get_reass()
-
-        self.vapi.nat_set_reass(timeout=reas_cfg1.ip4_timeout + 5,
-                                max_reass=reas_cfg1.ip4_max_reass * 2,
-                                max_frag=reas_cfg1.ip4_max_frag * 2)
-
-        reas_cfg2 = self.vapi.nat_get_reass()
-
-        self.assertEqual(reas_cfg1.ip4_timeout + 5, reas_cfg2.ip4_timeout)
-        self.assertEqual(reas_cfg1.ip4_max_reass * 2, reas_cfg2.ip4_max_reass)
-        self.assertEqual(reas_cfg1.ip4_max_frag * 2, reas_cfg2.ip4_max_frag)
-
-        self.vapi.nat_set_reass(drop_frag=1)
-        self.assertTrue(self.vapi.nat_get_reass().ip4_drop_frag)
-
-    def test_frag_in_order(self):
-        """ NAT44 translate fragments arriving in order """
-        self.nat44_add_address(self.nat_addr)
-        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
-        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
-                                                  is_inside=0)
-
-        data = "A" * 4 + "B" * 16 + "C" * 3
-        self.tcp_port_in = random.randint(1025, 65535)
-
-        reass = self.vapi.nat_reass_dump()
-        reass_n_start = len(reass)
-
-        # in2out
-        pkts = self.create_stream_frag(self.pg0,
-                                       self.pg1.remote_ip4,
-                                       self.tcp_port_in,
-                                       20,
-                                       data)
-        self.pg0.add_stream(pkts)
-        self.pg_enable_capture(self.pg_interfaces)
-        self.pg_start()
-        frags = self.pg1.get_capture(len(pkts))
-        p = self.reass_frags_and_verify(frags,
-                                        self.nat_addr,
-                                        self.pg1.remote_ip4)
-        self.assertEqual(p[TCP].dport, 20)
-        self.assertNotEqual(p[TCP].sport, self.tcp_port_in)
-        self.tcp_port_out = p[TCP].sport
-        self.assertEqual(data, p[Raw].load)
-
-        # out2in
-        pkts = self.create_stream_frag(self.pg1,
-                                       self.nat_addr,
-                                       20,
-                                       self.tcp_port_out,
-                                       data)
-        self.pg1.add_stream(pkts)
-        self.pg_enable_capture(self.pg_interfaces)
-        self.pg_start()
-        frags = self.pg0.get_capture(len(pkts))
-        p = self.reass_frags_and_verify(frags,
-                                        self.pg1.remote_ip4,
-                                        self.pg0.remote_ip4)
-        self.assertEqual(p[TCP].sport, 20)
-        self.assertEqual(p[TCP].dport, self.tcp_port_in)
-        self.assertEqual(data, p[Raw].load)
-
-        reass = self.vapi.nat_reass_dump()
-        reass_n_end = len(reass)
-
-        self.assertEqual(reass_n_end - reass_n_start, 2)
-
-    def test_reass_hairpinning(self):
-        """ NAT44 fragments hairpinning """
-        host = self.pg0.remote_hosts[0]
-        server = self.pg0.remote_hosts[1]
-        host_in_port = random.randint(1025, 65535)
-        host_out_port = 0
-        server_in_port = random.randint(1025, 65535)
-        server_out_port = random.randint(1025, 65535)
-        data = "A" * 4 + "B" * 16 + "C" * 3
-
-        self.nat44_add_address(self.nat_addr)
-        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
-        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
-                                                  is_inside=0)
-        # add static mapping for server
-        self.nat44_add_static_mapping(server.ip4, self.nat_addr,
-                                      server_in_port, server_out_port,
-                                      proto=IP_PROTOS.tcp)
-
-        # send packet from host to server
-        pkts = self.create_stream_frag(self.pg0,
-                                       self.nat_addr,
-                                       host_in_port,
-                                       server_out_port,
-                                       data)
-        self.pg0.add_stream(pkts)
-        self.pg_enable_capture(self.pg_interfaces)
-        self.pg_start()
-        frags = self.pg0.get_capture(len(pkts))
-        p = self.reass_frags_and_verify(frags,
-                                        self.nat_addr,
-                                        server.ip4)
-        self.assertNotEqual(p[TCP].sport, host_in_port)
-        self.assertEqual(p[TCP].dport, server_in_port)
-        self.assertEqual(data, p[Raw].load)
-
-    def test_frag_out_of_order(self):
-        """ NAT44 translate fragments arriving out of order """
-        self.nat44_add_address(self.nat_addr)
-        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
-        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
-                                                  is_inside=0)
-
-        data = "A" * 4 + "B" * 16 + "C" * 3
-        random.randint(1025, 65535)
-
-        # in2out
-        pkts = self.create_stream_frag(self.pg0,
-                                       self.pg1.remote_ip4,
-                                       self.tcp_port_in,
-                                       20,
-                                       data)
-        pkts.reverse()
-        self.pg0.add_stream(pkts)
-        self.pg_enable_capture(self.pg_interfaces)
-        self.pg_start()
-        frags = self.pg1.get_capture(len(pkts))
-        p = self.reass_frags_and_verify(frags,
-                                        self.nat_addr,
-                                        self.pg1.remote_ip4)
-        self.assertEqual(p[TCP].dport, 20)
-        self.assertNotEqual(p[TCP].sport, self.tcp_port_in)
-        self.tcp_port_out = p[TCP].sport
-        self.assertEqual(data, p[Raw].load)
+        self.verify_capture_out(capture)
 
         # out2in
-        pkts = self.create_stream_frag(self.pg1,
-                                       self.nat_addr,
-                                       20,
-                                       self.tcp_port_out,
-                                       data)
-        pkts.reverse()
+        pkts = self.create_stream_out(self.pg1)
         self.pg1.add_stream(pkts)
-        self.pg_enable_capture(self.pg_interfaces)
-        self.pg_start()
-        frags = self.pg0.get_capture(len(pkts))
-        p = self.reass_frags_and_verify(frags,
-                                        self.pg1.remote_ip4,
-                                        self.pg0.remote_ip4)
-        self.assertEqual(p[TCP].sport, 20)
-        self.assertEqual(p[TCP].dport, self.tcp_port_in)
-        self.assertEqual(data, p[Raw].load)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg0.get_capture(len(pkts))
+        self.verify_capture_in(capture, self.pg0)
 
-    def test_port_restricted(self):
-        """ Port restricted NAT44 (MAP-E CE) """
+    def test_multiple_vrf(self):
+        """ Multiple VRF setup """
+        external_addr = '1.2.3.4'
+        external_port = 80
+        local_port = 8080
+        port = 0
+
+        self.vapi.nat44_forwarding_enable_disable(1)
         self.nat44_add_address(self.nat_addr)
         self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
-        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
+        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index,
+                                                  is_inside=0)
+        self.vapi.nat44_interface_add_del_output_feature(self.pg1.sw_if_index,
+                                                         is_inside=0)
+        self.vapi.nat44_interface_add_del_feature(self.pg5.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg5.sw_if_index,
+                                                  is_inside=0)
+        self.vapi.nat44_interface_add_del_feature(self.pg6.sw_if_index,
                                                   is_inside=0)
-        self.vapi.cli("nat addr-port-assignment-alg map-e psid 10 "
-                      "psid-offset 6 psid-len 6")
+        self.nat44_add_static_mapping(self.pg5.remote_ip4, external_addr,
+                                      local_port, external_port, vrf_id=1,
+                                      proto=IP_PROTOS.tcp, out2in_only=1)
+        self.nat44_add_static_mapping(
+             self.pg0.remote_ip4, external_sw_if_index=self.pg0.sw_if_index,
+             local_port=local_port, vrf_id=0, external_port=external_port,
+             proto=IP_PROTOS.tcp, out2in_only=1)
 
-        p = (Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac) /
-             IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4) /
-             TCP(sport=4567, dport=22))
-        self.pg0.add_stream(p)
+        # from client to service (both VRF1)
+        p = (Ether(src=self.pg6.remote_mac, dst=self.pg6.local_mac) /
+             IP(src=self.pg6.remote_ip4, dst=external_addr) /
+             TCP(sport=12345, dport=external_port))
+        self.pg6.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg5.get_capture(1)
+        p = capture[0]
+        try:
+            ip = p[IP]
+            tcp = p[TCP]
+            self.assertEqual(ip.dst, self.pg5.remote_ip4)
+            self.assertEqual(tcp.dport, local_port)
+            self.assert_packet_checksums_valid(p)
+        except:
+            self.logger.error(ppp("Unexpected or invalid packet:", p))
+            raise
+
+        # from service back to client (both VRF1)
+        p = (Ether(src=self.pg5.remote_mac, dst=self.pg5.local_mac) /
+             IP(src=self.pg5.remote_ip4, dst=self.pg6.remote_ip4) /
+             TCP(sport=local_port, dport=12345))
+        self.pg5.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg6.get_capture(1)
+        p = capture[0]
+        try:
+            ip = p[IP]
+            tcp = p[TCP]
+            self.assertEqual(ip.src, external_addr)
+            self.assertEqual(tcp.sport, external_port)
+            self.assert_packet_checksums_valid(p)
+        except:
+            self.logger.error(ppp("Unexpected or invalid packet:", p))
+            raise
+
+        # dynamic NAT from VRF1 to VRF0 (output-feature)
+        p = (Ether(src=self.pg5.remote_mac, dst=self.pg5.local_mac) /
+             IP(src=self.pg5.remote_ip4, dst=self.pg1.remote_ip4) /
+             TCP(sport=2345, dport=22))
+        self.pg5.add_stream(p)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
         capture = self.pg1.get_capture(1)
@@ -3833,232 +5651,405 @@ class TestNAT44(MethodHolder):
         try:
             ip = p[IP]
             tcp = p[TCP]
-            self.assertEqual(ip.dst, self.pg1.remote_ip4)
             self.assertEqual(ip.src, self.nat_addr)
-            self.assertEqual(tcp.dport, 22)
-            self.assertNotEqual(tcp.sport, 4567)
-            self.assertEqual((tcp.sport >> 6) & 63, 10)
-            self.check_tcp_checksum(p)
-            self.check_ip_checksum(p)
+            self.assertNotEqual(tcp.sport, 2345)
+            self.assert_packet_checksums_valid(p)
+            port = tcp.sport
         except:
             self.logger.error(ppp("Unexpected or invalid packet:", p))
             raise
 
-    def test_twice_nat(self):
-        """ Twice NAT44 """
-        twice_nat_addr = '10.0.1.3'
-        port_in = 8080
-        port_out = 80
-        eh_port_out = 4567
-        eh_port_in = 0
-        self.nat44_add_address(self.nat_addr)
-        self.nat44_add_address(twice_nat_addr, twice_nat=1)
-        self.nat44_add_static_mapping(self.pg0.remote_ip4, self.nat_addr,
-                                      port_in, port_out, proto=IP_PROTOS.tcp,
-                                      twice_nat=1)
-        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
-        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
-                                                  is_inside=0)
-
         p = (Ether(src=self.pg1.remote_mac, dst=self.pg1.local_mac) /
              IP(src=self.pg1.remote_ip4, dst=self.nat_addr) /
-             TCP(sport=eh_port_out, dport=port_out))
+             TCP(sport=22, dport=port))
         self.pg1.add_stream(p)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
+        capture = self.pg5.get_capture(1)
+        p = capture[0]
+        try:
+            ip = p[IP]
+            tcp = p[TCP]
+            self.assertEqual(ip.dst, self.pg5.remote_ip4)
+            self.assertEqual(tcp.dport, 2345)
+            self.assert_packet_checksums_valid(p)
+        except:
+            self.logger.error(ppp("Unexpected or invalid packet:", p))
+            raise
+
+        # from client VRF1 to service VRF0
+        p = (Ether(src=self.pg6.remote_mac, dst=self.pg6.local_mac) /
+             IP(src=self.pg6.remote_ip4, dst=self.pg0.local_ip4) /
+             TCP(sport=12346, dport=external_port))
+        self.pg6.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
         capture = self.pg0.get_capture(1)
         p = capture[0]
         try:
             ip = p[IP]
             tcp = p[TCP]
             self.assertEqual(ip.dst, self.pg0.remote_ip4)
-            self.assertEqual(ip.src, twice_nat_addr)
-            self.assertEqual(tcp.dport, port_in)
-            self.assertNotEqual(tcp.sport, eh_port_out)
-            eh_port_in = tcp.sport
-            self.check_tcp_checksum(p)
-            self.check_ip_checksum(p)
+            self.assertEqual(tcp.dport, local_port)
+            self.assert_packet_checksums_valid(p)
         except:
             self.logger.error(ppp("Unexpected or invalid packet:", p))
             raise
 
+        # from service VRF0 back to client VRF1
         p = (Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac) /
-             IP(src=self.pg0.remote_ip4, dst=twice_nat_addr) /
-             TCP(sport=port_in, dport=eh_port_in))
+             IP(src=self.pg0.remote_ip4, dst=self.pg6.remote_ip4) /
+             TCP(sport=local_port, dport=12346))
         self.pg0.add_stream(p)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        capture = self.pg1.get_capture(1)
+        capture = self.pg6.get_capture(1)
         p = capture[0]
         try:
             ip = p[IP]
             tcp = p[TCP]
-            self.assertEqual(ip.dst, self.pg1.remote_ip4)
-            self.assertEqual(ip.src, self.nat_addr)
-            self.assertEqual(tcp.dport, eh_port_out)
-            self.assertEqual(tcp.sport, port_out)
-            self.check_tcp_checksum(p)
-            self.check_ip_checksum(p)
+            self.assertEqual(ip.src, self.pg0.local_ip4)
+            self.assertEqual(tcp.sport, external_port)
+            self.assert_packet_checksums_valid(p)
         except:
             self.logger.error(ppp("Unexpected or invalid packet:", p))
             raise
 
-    def test_twice_nat_lb(self):
-        """ Twice NAT44 local service load balancing """
-        external_addr_n = socket.inet_pton(socket.AF_INET, self.nat_addr)
-        twice_nat_addr = '10.0.1.3'
-        local_port = 8080
-        external_port = 80
-        eh_port_out = 4567
-        eh_port_in = 0
-        server1 = self.pg0.remote_hosts[0]
-        server2 = self.pg0.remote_hosts[1]
+        # from client VRF0 to service VRF1
+        p = (Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac) /
+             IP(src=self.pg0.remote_ip4, dst=external_addr) /
+             TCP(sport=12347, dport=external_port))
+        self.pg0.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg5.get_capture(1)
+        p = capture[0]
+        try:
+            ip = p[IP]
+            tcp = p[TCP]
+            self.assertEqual(ip.dst, self.pg5.remote_ip4)
+            self.assertEqual(tcp.dport, local_port)
+            self.assert_packet_checksums_valid(p)
+        except:
+            self.logger.error(ppp("Unexpected or invalid packet:", p))
+            raise
 
-        locals = [{'addr': server1.ip4n,
-                   'port': local_port,
-                   'probability': 50},
-                  {'addr': server2.ip4n,
-                   'port': local_port,
-                   'probability': 50}]
+        # from service VRF1 back to client VRF0
+        p = (Ether(src=self.pg5.remote_mac, dst=self.pg5.local_mac) /
+             IP(src=self.pg5.remote_ip4, dst=self.pg0.remote_ip4) /
+             TCP(sport=local_port, dport=12347))
+        self.pg5.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg0.get_capture(1)
+        p = capture[0]
+        try:
+            ip = p[IP]
+            tcp = p[TCP]
+            self.assertEqual(ip.src, external_addr)
+            self.assertEqual(tcp.sport, external_port)
+            self.assert_packet_checksums_valid(p)
+        except:
+            self.logger.error(ppp("Unexpected or invalid packet:", p))
+            raise
 
-        self.nat44_add_address(self.nat_addr)
-        self.nat44_add_address(twice_nat_addr, twice_nat=1)
+        # from client to server (both VRF1, no translation)
+        p = (Ether(src=self.pg6.remote_mac, dst=self.pg6.local_mac) /
+             IP(src=self.pg6.remote_ip4, dst=self.pg5.remote_ip4) /
+             TCP(sport=12348, dport=local_port))
+        self.pg6.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg5.get_capture(1)
+        p = capture[0]
+        try:
+            ip = p[IP]
+            tcp = p[TCP]
+            self.assertEqual(ip.dst, self.pg5.remote_ip4)
+            self.assertEqual(tcp.dport, local_port)
+            self.assert_packet_checksums_valid(p)
+        except:
+            self.logger.error(ppp("Unexpected or invalid packet:", p))
+            raise
 
-        self.vapi.nat44_add_del_lb_static_mapping(external_addr_n,
-                                                  external_port,
-                                                  IP_PROTOS.tcp,
-                                                  twice_nat=1,
-                                                  local_num=len(locals),
-                                                  locals=locals)
-        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
-        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
-                                                  is_inside=0)
+        # from server back to client (both VRF1, no translation)
+        p = (Ether(src=self.pg5.remote_mac, dst=self.pg5.local_mac) /
+             IP(src=self.pg5.remote_ip4, dst=self.pg6.remote_ip4) /
+             TCP(sport=local_port, dport=12348))
+        self.pg5.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg6.get_capture(1)
+        p = capture[0]
+        try:
+            ip = p[IP]
+            tcp = p[TCP]
+            self.assertEqual(ip.src, self.pg5.remote_ip4)
+            self.assertEqual(tcp.sport, local_port)
+            self.assert_packet_checksums_valid(p)
+        except:
+            self.logger.error(ppp("Unexpected or invalid packet:", p))
+            raise
 
-        p = (Ether(src=self.pg1.remote_mac, dst=self.pg1.local_mac) /
-             IP(src=self.pg1.remote_ip4, dst=self.nat_addr) /
-             TCP(sport=eh_port_out, dport=external_port))
-        self.pg1.add_stream(p)
+        # from client VRF1 to server VRF0 (no translation)
+        p = (Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac) /
+             IP(src=self.pg0.remote_ip4, dst=self.pg6.remote_ip4) /
+             TCP(sport=local_port, dport=12349))
+        self.pg0.add_stream(p)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        capture = self.pg0.get_capture(1)
+        capture = self.pg6.get_capture(1)
         p = capture[0]
-        server = None
         try:
             ip = p[IP]
             tcp = p[TCP]
-            self.assertEqual(ip.src, twice_nat_addr)
-            self.assertIn(ip.dst, [server1.ip4, server2.ip4])
-            if ip.dst == server1.ip4:
-                server = server1
-            else:
-                server = server2
-            self.assertNotEqual(tcp.sport, eh_port_out)
-            eh_port_in = tcp.sport
-            self.assertEqual(tcp.dport, local_port)
-            self.check_tcp_checksum(p)
-            self.check_ip_checksum(p)
+            self.assertEqual(ip.src, self.pg0.remote_ip4)
+            self.assertEqual(tcp.sport, local_port)
+            self.assert_packet_checksums_valid(p)
         except:
             self.logger.error(ppp("Unexpected or invalid packet:", p))
             raise
 
-        p = (Ether(src=server.mac, dst=self.pg0.local_mac) /
-             IP(src=server.ip4, dst=twice_nat_addr) /
-             TCP(sport=local_port, dport=eh_port_in))
+        # from server VRF0 back to client VRF1 (no translation)
+        p = (Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac) /
+             IP(src=self.pg0.remote_ip4, dst=self.pg6.remote_ip4) /
+             TCP(sport=local_port, dport=12349))
         self.pg0.add_stream(p)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        capture = self.pg1.get_capture(1)
+        capture = self.pg6.get_capture(1)
         p = capture[0]
         try:
             ip = p[IP]
             tcp = p[TCP]
-            self.assertEqual(ip.src, self.nat_addr)
-            self.assertEqual(ip.dst, self.pg1.remote_ip4)
-            self.assertEqual(tcp.sport, external_port)
-            self.assertEqual(tcp.dport, eh_port_out)
-            self.check_tcp_checksum(p)
-            self.check_ip_checksum(p)
+            self.assertEqual(ip.src, self.pg0.remote_ip4)
+            self.assertEqual(tcp.sport, local_port)
+            self.assert_packet_checksums_valid(p)
         except:
             self.logger.error(ppp("Unexpected or invalid packet:", p))
             raise
 
-    def test_twice_nat_interface_addr(self):
-        """ Acquire twice NAT44 addresses from interface """
-        self.vapi.nat44_add_interface_addr(self.pg7.sw_if_index, twice_nat=1)
+        # from client VRF0 to server VRF1 (no translation)
+        p = (Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac) /
+             IP(src=self.pg0.remote_ip4, dst=self.pg5.remote_ip4) /
+             TCP(sport=12344, dport=local_port))
+        self.pg0.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg5.get_capture(1)
+        p = capture[0]
+        try:
+            ip = p[IP]
+            tcp = p[TCP]
+            self.assertEqual(ip.dst, self.pg5.remote_ip4)
+            self.assertEqual(tcp.dport, local_port)
+            self.assert_packet_checksums_valid(p)
+        except:
+            self.logger.error(ppp("Unexpected or invalid packet:", p))
+            raise
+
+        # from server VRF1 back to client VRF0 (no translation)
+        p = (Ether(src=self.pg5.remote_mac, dst=self.pg5.local_mac) /
+             IP(src=self.pg5.remote_ip4, dst=self.pg0.remote_ip4) /
+             TCP(sport=local_port, dport=12344))
+        self.pg5.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg0.get_capture(1)
+        p = capture[0]
+        try:
+            ip = p[IP]
+            tcp = p[TCP]
+            self.assertEqual(ip.src, self.pg5.remote_ip4)
+            self.assertEqual(tcp.sport, local_port)
+            self.assert_packet_checksums_valid(p)
+        except:
+            self.logger.error(ppp("Unexpected or invalid packet:", p))
+            raise
+
+    @unittest.skipUnless(running_extended_tests, "part of extended tests")
+    def test_session_timeout(self):
+        """ NAT44 session timeouts """
+        self.nat44_add_address(self.nat_addr)
+        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
+                                                  is_inside=0)
+        self.vapi.nat_set_timeouts(icmp=5)
+
+        max_sessions = 1000
+        pkts = []
+        for i in range(0, max_sessions):
+            src = "10.10.%u.%u" % ((i & 0xFF00) >> 8, i & 0xFF)
+            p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
+                 IP(src=src, dst=self.pg1.remote_ip4) /
+                 ICMP(id=1025, type='echo-request'))
+            pkts.append(p)
+        self.pg0.add_stream(pkts)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        self.pg1.get_capture(max_sessions)
+
+        sleep(10)
+
+        pkts = []
+        for i in range(0, max_sessions):
+            src = "10.11.%u.%u" % ((i & 0xFF00) >> 8, i & 0xFF)
+            p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
+                 IP(src=src, dst=self.pg1.remote_ip4) /
+                 ICMP(id=1026, type='echo-request'))
+            pkts.append(p)
+        self.pg0.add_stream(pkts)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        self.pg1.get_capture(max_sessions)
+
+        nsessions = 0
+        users = self.vapi.nat44_user_dump()
+        for user in users:
+            nsessions = nsessions + user.nsessions
+        self.assertLess(nsessions, 2 * max_sessions)
+
+    @unittest.skipUnless(running_extended_tests, "part of extended tests")
+    def test_session_rst_timeout(self):
+        """ NAT44 session RST timeouts """
+        self.nat44_add_address(self.nat_addr)
+        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
+                                                  is_inside=0)
+        self.vapi.nat_set_timeouts(tcp_transitory=5)
+
+        self.initiate_tcp_session(self.pg0, self.pg1)
+        p = (Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac) /
+             IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4) /
+             TCP(sport=self.tcp_port_in, dport=self.tcp_external_port,
+                 flags="R"))
+        self.pg0.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        self.pg1.get_capture(1)
 
-        # no address in NAT pool
-        adresses = self.vapi.nat44_address_dump()
-        self.assertEqual(0, len(adresses))
+        sleep(6)
 
-        # configure interface address and check NAT address pool
-        self.pg7.config_ip4()
-        adresses = self.vapi.nat44_address_dump()
-        self.assertEqual(1, len(adresses))
-        self.assertEqual(adresses[0].ip_address[0:4], self.pg7.local_ip4n)
-        self.assertEqual(adresses[0].twice_nat, 1)
+        p = (Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac) /
+             IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4) /
+             TCP(sport=self.tcp_port_in + 1, dport=self.tcp_external_port + 1,
+                 flags="S"))
+        self.pg0.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        self.pg1.get_capture(1)
 
-        # remove interface address and check NAT address pool
-        self.pg7.unconfig_ip4()
-        adresses = self.vapi.nat44_address_dump()
-        self.assertEqual(0, len(adresses))
+        nsessions = 0
+        users = self.vapi.nat44_user_dump()
+        self.assertEqual(len(users), 1)
+        self.assertEqual(users[0].ip_address, self.pg0.remote_ip4n)
+        self.assertEqual(users[0].nsessions, 1)
 
-    def test_ipfix_max_frags(self):
-        """ IPFIX logging maximum fragments pending reassembly exceeded """
+    @unittest.skipUnless(running_extended_tests, "part of extended tests")
+    def test_session_limit_per_user(self):
+        """ Maximum sessions per user limit """
         self.nat44_add_address(self.nat_addr)
         self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
         self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
                                                   is_inside=0)
-        self.vapi.nat_set_reass(max_frag=0)
-        self.vapi.set_ipfix_exporter(collector_address=self.pg3.remote_ip4n,
-                                     src_address=self.pg3.local_ip4n,
+        self.vapi.set_ipfix_exporter(collector_address=self.pg2.remote_ip4n,
+                                     src_address=self.pg2.local_ip4n,
                                      path_mtu=512,
                                      template_interval=10)
+        self.vapi.nat_set_timeouts(udp=5)
+
+        # get maximum number of translations per user
+        nat44_config = self.vapi.nat_show_config()
+
+        pkts = []
+        for port in range(0, nat44_config.max_translations_per_user):
+            p = (Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac) /
+                 IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4) /
+                 UDP(sport=1025 + port, dport=1025 + port))
+            pkts.append(p)
+
+        self.pg0.add_stream(pkts)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg1.get_capture(len(pkts))
+
         self.vapi.nat_ipfix(domain_id=self.ipfix_domain_id,
                             src_port=self.ipfix_src_port)
 
-        data = "A" * 4 + "B" * 16 + "C" * 3
-        self.tcp_port_in = random.randint(1025, 65535)
-        pkts = self.create_stream_frag(self.pg0,
-                                       self.pg1.remote_ip4,
-                                       self.tcp_port_in,
-                                       20,
-                                       data)
-        self.pg0.add_stream(pkts[-1])
+        p = (Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac) /
+             IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4) /
+             UDP(sport=3001, dport=3002))
+        self.pg0.add_stream(p)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        frags = self.pg1.get_capture(0)
+        capture = self.pg1.assert_nothing_captured()
+
+        # verify IPFIX logging
         self.vapi.cli("ipfix flush")  # FIXME this should be an API call
-        capture = self.pg3.get_capture(9)
+        sleep(1)
+        capture = self.pg2.get_capture(10)
         ipfix = IPFIXDecoder()
         # first load template
         for p in capture:
             self.assertTrue(p.haslayer(IPFIX))
-            self.assertEqual(p[IP].src, self.pg3.local_ip4)
-            self.assertEqual(p[IP].dst, self.pg3.remote_ip4)
-            self.assertEqual(p[UDP].sport, self.ipfix_src_port)
-            self.assertEqual(p[UDP].dport, 4739)
-            self.assertEqual(p[IPFIX].observationDomainID,
-                             self.ipfix_domain_id)
             if p.haslayer(Template):
                 ipfix.add_template(p.getlayer(Template))
         # verify events in data set
         for p in capture:
             if p.haslayer(Data):
                 data = ipfix.decode_data_set(p.getlayer(Set))
-                self.verify_ipfix_max_fragments_ip4(data, 0,
-                                                    self.pg0.remote_ip4n)
+                self.verify_ipfix_max_entries_per_user(
+                    data,
+                    nat44_config.max_translations_per_user,
+                    self.pg0.remote_ip4n)
+
+        sleep(6)
+        p = (Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac) /
+             IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4) /
+             UDP(sport=3001, dport=3002))
+        self.pg0.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        self.pg1.get_capture(1)
+
+    def test_syslog_sess(self):
+        """ Test syslog session creation and deletion """
+        self.vapi.syslog_set_filter(SYSLOG_SEVERITY.INFO)
+        self.vapi.syslog_set_sender(self.pg2.remote_ip4n, self.pg2.local_ip4n)
+        self.nat44_add_address(self.nat_addr)
+        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
+                                                  is_inside=0)
+
+        p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
+             IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4) /
+             TCP(sport=self.tcp_port_in, dport=self.tcp_external_port))
+        self.pg0.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg1.get_capture(1)
+        self.tcp_port_out = capture[0][TCP].sport
+        capture = self.pg2.get_capture(1)
+        self.verify_syslog_sess(capture[0][Raw].load)
+
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        self.nat44_add_address(self.nat_addr, is_add=0)
+        capture = self.pg2.get_capture(1)
+        self.verify_syslog_sess(capture[0][Raw].load, False)
 
     def tearDown(self):
-        super(TestNAT44, self).tearDown()
+        super(TestNAT44EndpointDependent, self).tearDown()
         if not self.vpp_dead:
             self.logger.info(self.vapi.cli("show nat44 addresses"))
             self.logger.info(self.vapi.cli("show nat44 interfaces"))
             self.logger.info(self.vapi.cli("show nat44 static mappings"))
             self.logger.info(self.vapi.cli("show nat44 interface address"))
             self.logger.info(self.vapi.cli("show nat44 sessions detail"))
-            self.logger.info(self.vapi.cli("show nat virtual-reassembly"))
-            self.vapi.cli("nat addr-port-assignment-alg default")
+            self.logger.info(self.vapi.cli("show nat44 hash tables detail"))
+            self.logger.info(self.vapi.cli("show nat timeouts"))
             self.clear_nat44()
+            self.vapi.cli("clear logging")
 
 
 class TestNAT44Out2InDPO(MethodHolder):
@@ -4072,6 +6063,7 @@ class TestNAT44Out2InDPO(MethodHolder):
     @classmethod
     def setUpClass(cls):
         super(TestNAT44Out2InDPO, cls).setUpClass()
+        cls.vapi.cli("set log class nat level debug")
 
         try:
             cls.tcp_port_in = 6303
@@ -4114,12 +6106,15 @@ class TestNAT44Out2InDPO(MethodHolder):
         self.src_ip6_pfx_len = 96
         self.vapi.map_add_domain(self.dst_ip6_pfx_n, self.dst_ip6_pfx_len,
                                  self.src_ip6_pfx_n, self.src_ip6_pfx_len,
-                                 '\x00\x00\x00\x00', 0, is_translation=1,
-                                 is_rfc6052=1)
+                                 '\x00\x00\x00\x00', 0)
 
+    @unittest.skip('Temporary disabled')
     def test_464xlat_ce(self):
         """ Test 464XLAT CE with NAT44 """
 
+        nat_config = self.vapi.nat_show_config()
+        self.assertEqual(1, nat_config.out2in_dpo)
+
         self.configure_xlat()
 
         self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
@@ -4152,6 +6147,7 @@ class TestNAT44Out2InDPO(MethodHolder):
             self.vapi.nat44_add_del_address_range(self.nat_addr_n,
                                                   self.nat_addr_n, is_add=0)
 
+    @unittest.skip('Temporary disabled')
     def test_464xlat_ce_no_nat(self):
         """ Test 464XLAT CE without NAT44 """
 
@@ -4189,6 +6185,7 @@ class TestDeterministicNAT(MethodHolder):
     @classmethod
     def setUpClass(cls):
         super(TestDeterministicNAT, cls).setUpClass()
+        cls.vapi.cli("set log class nat level debug")
 
         try:
             cls.tcp_port_in = 6303
@@ -4273,18 +6270,16 @@ class TestDeterministicNAT(MethodHolder):
 
         return pkts
 
-    def verify_capture_out(self, capture, nat_ip=None, packet_num=3):
+    def verify_capture_out(self, capture, nat_ip=None):
         """
         Verify captured packets on outside network
 
         :param capture: Captured packets
         :param nat_ip: Translated IP address (Default use global NAT address)
         :param same_port: Sorce port number is not translated (Default False)
-        :param packet_num: Expected number of packets (Default 3)
         """
         if nat_ip is None:
             nat_ip = self.nat_addr
-        self.assertEqual(packet_num, len(capture))
         for packet in capture:
             try:
                 self.assertEqual(packet[IP].src, nat_ip)
@@ -4299,67 +6294,6 @@ class TestDeterministicNAT(MethodHolder):
                                       "(outside network):", packet))
                 raise
 
-    def initiate_tcp_session(self, in_if, out_if):
-        """
-        Initiates TCP session
-
-        :param in_if: Inside interface
-        :param out_if: Outside interface
-        """
-        try:
-            # SYN packet in->out
-            p = (Ether(src=in_if.remote_mac, dst=in_if.local_mac) /
-                 IP(src=in_if.remote_ip4, dst=out_if.remote_ip4) /
-                 TCP(sport=self.tcp_port_in, dport=self.tcp_external_port,
-                     flags="S"))
-            in_if.add_stream(p)
-            self.pg_enable_capture(self.pg_interfaces)
-            self.pg_start()
-            capture = out_if.get_capture(1)
-            p = capture[0]
-            self.tcp_port_out = p[TCP].sport
-
-            # SYN + ACK packet out->in
-            p = (Ether(src=out_if.remote_mac, dst=out_if.local_mac) /
-                 IP(src=out_if.remote_ip4, dst=self.nat_addr) /
-                 TCP(sport=self.tcp_external_port, dport=self.tcp_port_out,
-                     flags="SA"))
-            out_if.add_stream(p)
-            self.pg_enable_capture(self.pg_interfaces)
-            self.pg_start()
-            in_if.get_capture(1)
-
-            # ACK packet in->out
-            p = (Ether(src=in_if.remote_mac, dst=in_if.local_mac) /
-                 IP(src=in_if.remote_ip4, dst=out_if.remote_ip4) /
-                 TCP(sport=self.tcp_port_in, dport=self.tcp_external_port,
-                     flags="A"))
-            in_if.add_stream(p)
-            self.pg_enable_capture(self.pg_interfaces)
-            self.pg_start()
-            out_if.get_capture(1)
-
-        except:
-            self.logger.error("TCP 3 way handshake failed")
-            raise
-
-    def verify_ipfix_max_entries_per_user(self, data):
-        """
-        Verify IPFIX maximum entries per user exceeded event
-
-        :param data: Decoded IPFIX data records
-        """
-        self.assertEqual(1, len(data))
-        record = data[0]
-        # natEvent
-        self.assertEqual(ord(record[230]), 13)
-        # natQuotaExceededEvent
-        self.assertEqual('\x03\x00\x00\x00', record[466])
-        # maxEntriesPerUser
-        self.assertEqual('\xe8\x03\x00\x00', record[473])
-        # sourceIPv4Address
-        self.assertEqual(self.pg0.remote_ip4n, record[8])
-
     def test_deterministic_mode(self):
         """ NAT plugin run deterministic mode """
         in_addr = '172.16.255.0'
@@ -4395,14 +6329,14 @@ class TestDeterministicNAT(MethodHolder):
 
     def test_set_timeouts(self):
         """ Set deterministic NAT timeouts """
-        timeouts_before = self.vapi.nat_det_get_timeouts()
+        timeouts_before = self.vapi.nat_get_timeouts()
 
-        self.vapi.nat_det_set_timeouts(timeouts_before.udp + 10,
-                                       timeouts_before.tcp_established + 10,
-                                       timeouts_before.tcp_transitory + 10,
-                                       timeouts_before.icmp + 10)
+        self.vapi.nat_set_timeouts(timeouts_before.udp + 10,
+                                   timeouts_before.tcp_established + 10,
+                                   timeouts_before.tcp_transitory + 10,
+                                   timeouts_before.icmp + 10)
 
-        timeouts_after = self.vapi.nat_det_get_timeouts()
+        timeouts_after = self.vapi.nat_get_timeouts()
 
         self.assertNotEqual(timeouts_before.udp, timeouts_after.udp)
         self.assertNotEqual(timeouts_before.icmp, timeouts_after.icmp)
@@ -4705,7 +6639,7 @@ class TestDeterministicNAT(MethodHolder):
             self.logger.error("TCP session termination failed")
             raise
 
-    @unittest.skipUnless(running_extended_tests(), "part of extended tests")
+    @unittest.skipUnless(running_extended_tests, "part of extended tests")
     def test_session_timeout(self):
         """ Deterministic NAT session timeouts """
         self.vapi.nat_det_add_del_map(self.pg0.remote_ip4n,
@@ -4717,7 +6651,7 @@ class TestDeterministicNAT(MethodHolder):
                                                   is_inside=0)
 
         self.initiate_tcp_session(self.pg0, self.pg1)
-        self.vapi.nat_det_set_timeouts(5, 5, 5, 5)
+        self.vapi.nat_set_timeouts(5, 5, 5, 5)
         pkts = self.create_stream_in(self.pg0, self.pg1)
         self.pg0.add_stream(pkts)
         self.pg_enable_capture(self.pg_interfaces)
@@ -4728,7 +6662,7 @@ class TestDeterministicNAT(MethodHolder):
         dms = self.vapi.nat_det_map_dump()
         self.assertEqual(0, dms[0].ses_num)
 
-    @unittest.skipUnless(running_extended_tests(), "part of extended tests")
+    @unittest.skipUnless(running_extended_tests, "part of extended tests")
     def test_session_limit_per_user(self):
         """ Deterministic NAT maximum sessions per user limit """
         self.vapi.nat_det_add_del_map(self.pg0.remote_ip4n,
@@ -4794,14 +6728,16 @@ class TestDeterministicNAT(MethodHolder):
         for p in capture:
             if p.haslayer(Data):
                 data = ipfix.decode_data_set(p.getlayer(Set))
-                self.verify_ipfix_max_entries_per_user(data)
+                self.verify_ipfix_max_entries_per_user(data,
+                                                       1000,
+                                                       self.pg0.remote_ip4n)
 
     def clear_nat_det(self):
         """
         Clear deterministic NAT configuration.
         """
         self.vapi.nat_ipfix(enable=0)
-        self.vapi.nat_det_set_timeouts()
+        self.vapi.nat_set_timeouts()
         deterministic_mappings = self.vapi.nat_det_map_dump()
         for dsm in deterministic_mappings:
             self.vapi.nat_det_add_del_map(dsm.in_addr,
@@ -4820,10 +6756,9 @@ class TestDeterministicNAT(MethodHolder):
         super(TestDeterministicNAT, self).tearDown()
         if not self.vpp_dead:
             self.logger.info(self.vapi.cli("show nat44 interfaces"))
+            self.logger.info(self.vapi.cli("show nat timeouts"))
             self.logger.info(
                 self.vapi.cli("show nat44 deterministic mappings"))
-            self.logger.info(
-                self.vapi.cli("show nat44 deterministic timeouts"))
             self.logger.info(
                 self.vapi.cli("show nat44 deterministic sessions"))
             self.clear_nat_det()
@@ -4849,6 +6784,7 @@ class TestNAT64(MethodHolder):
             cls.udp_port_out = 6304
             cls.icmp_id_in = 6305
             cls.icmp_id_out = 6305
+            cls.tcp_external_port = 80
             cls.nat_addr = '10.0.0.3'
             cls.nat_addr_n = socket.inet_pton(socket.AF_INET, cls.nat_addr)
             cls.vrf1_id = 10
@@ -4858,7 +6794,7 @@ class TestNAT64(MethodHolder):
             cls.ipfix_src_port = 4739
             cls.ipfix_domain_id = 1
 
-            cls.create_pg_interfaces(range(5))
+            cls.create_pg_interfaces(range(6))
             cls.ip6_interfaces = list(cls.pg_interfaces[0:1])
             cls.ip6_interfaces.append(cls.pg_interfaces[2])
             cls.ip4_interfaces = list(cls.pg_interfaces[1:2])
@@ -4885,10 +6821,65 @@ class TestNAT64(MethodHolder):
             cls.pg3.config_ip6()
             cls.pg3.configure_ipv6_neighbors()
 
+            cls.pg5.admin_up()
+            cls.pg5.config_ip6()
+
         except Exception:
             super(TestNAT64, cls).tearDownClass()
             raise
 
+    def test_nat64_inside_interface_handles_neighbor_advertisement(self):
+        """ NAT64 inside interface handles Neighbor Advertisement """
+
+        self.vapi.nat64_add_del_interface(self.pg5.sw_if_index)
+
+        # Try to send ping
+        ping = (Ether(dst=self.pg5.local_mac, src=self.pg5.remote_mac) /
+                IPv6(src=self.pg5.remote_ip6, dst=self.pg5.local_ip6) /
+                ICMPv6EchoRequest())
+        pkts = [ping]
+        self.pg5.add_stream(pkts)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+
+        # Wait for Neighbor Solicitation
+        capture = self.pg5.get_capture(len(pkts))
+        packet = capture[0]
+        try:
+            self.assertEqual(packet[IPv6].src, self.pg5.local_ip6)
+            self.assertEqual(packet.haslayer(ICMPv6ND_NS), 1)
+            tgt = packet[ICMPv6ND_NS].tgt
+        except:
+            self.logger.error(ppp("Unexpected or invalid packet:", packet))
+            raise
+
+        # Send Neighbor Advertisement
+        p = (Ether(dst=self.pg5.local_mac, src=self.pg5.remote_mac) /
+             IPv6(src=self.pg5.remote_ip6, dst=self.pg5.local_ip6) /
+             ICMPv6ND_NA(tgt=tgt) /
+             ICMPv6NDOptDstLLAddr(lladdr=self.pg5.remote_mac))
+        pkts = [p]
+        self.pg5.add_stream(pkts)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+
+        # Try to send ping again
+        pkts = [ping]
+        self.pg5.add_stream(pkts)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+
+        # Wait for ping reply
+        capture = self.pg5.get_capture(len(pkts))
+        packet = capture[0]
+        try:
+            self.assertEqual(packet[IPv6].src, self.pg5.local_ip6)
+            self.assertEqual(packet[IPv6].dst, self.pg5.remote_ip6)
+            self.assertEqual(packet.haslayer(ICMPv6EchoReply), 1)
+        except:
+            self.logger.error(ppp("Unexpected or invalid packet:", packet))
+            raise
+
     def test_pool(self):
         """ Add/delete address to NAT64 pool """
         nat_addr = socket.inet_pton(socket.AF_INET, '1.2.3.4')
@@ -4958,6 +6949,8 @@ class TestNAT64(MethodHolder):
                 self.assertEqual(bibe.i_port, in_port)
                 self.assertEqual(bibe.o_port, out_port)
         self.assertEqual(static_bib_num, 1)
+        bibs = self.statistics.get_counter('/nat64/total-bibs')
+        self.assertEqual(bibs[0][0], 1)
 
         self.vapi.nat64_add_del_static_bib(in_addr,
                                            out_addr,
@@ -4971,26 +6964,26 @@ class TestNAT64(MethodHolder):
             if bibe.is_static:
                 static_bib_num += 1
         self.assertEqual(static_bib_num, 0)
+        bibs = self.statistics.get_counter('/nat64/total-bibs')
+        self.assertEqual(bibs[0][0], 0)
 
     def test_set_timeouts(self):
         """ Set NAT64 timeouts """
         # verify default values
-        timeouts = self.vapi.nat64_get_timeouts()
+        timeouts = self.vapi.nat_get_timeouts()
         self.assertEqual(timeouts.udp, 300)
         self.assertEqual(timeouts.icmp, 60)
-        self.assertEqual(timeouts.tcp_trans, 240)
-        self.assertEqual(timeouts.tcp_est, 7440)
-        self.assertEqual(timeouts.tcp_incoming_syn, 6)
+        self.assertEqual(timeouts.tcp_transitory, 240)
+        self.assertEqual(timeouts.tcp_established, 7440)
 
         # set and verify custom values
-        self.vapi.nat64_set_timeouts(udp=200, icmp=30, tcp_trans=250,
-                                     tcp_est=7450, tcp_incoming_syn=10)
-        timeouts = self.vapi.nat64_get_timeouts()
+        self.vapi.nat_set_timeouts(udp=200, icmp=30, tcp_transitory=250,
+                                   tcp_established=7450)
+        timeouts = self.vapi.nat_get_timeouts()
         self.assertEqual(timeouts.udp, 200)
         self.assertEqual(timeouts.icmp, 30)
-        self.assertEqual(timeouts.tcp_trans, 250)
-        self.assertEqual(timeouts.tcp_est, 7450)
-        self.assertEqual(timeouts.tcp_incoming_syn, 10)
+        self.assertEqual(timeouts.tcp_transitory, 250)
+        self.assertEqual(timeouts.tcp_established, 7450)
 
     def test_dynamic(self):
         """ NAT64 dynamic translation test """
@@ -5006,6 +6999,12 @@ class TestNAT64(MethodHolder):
         self.vapi.nat64_add_del_interface(self.pg1.sw_if_index, is_inside=0)
 
         # in2out
+        tcpn = self.statistics.get_counter('/err/nat64-in2out/TCP packets')
+        udpn = self.statistics.get_counter('/err/nat64-in2out/UDP packets')
+        icmpn = self.statistics.get_counter('/err/nat64-in2out/ICMP packets')
+        totaln = self.statistics.get_counter(
+            '/err/nat64-in2out/good in2out packets processed')
+
         pkts = self.create_stream_in_ip6(self.pg0, self.pg1)
         self.pg0.add_stream(pkts)
         self.pg_enable_capture(self.pg_interfaces)
@@ -5014,7 +7013,23 @@ class TestNAT64(MethodHolder):
         self.verify_capture_out(capture, nat_ip=self.nat_addr,
                                 dst_ip=self.pg1.remote_ip4)
 
+        err = self.statistics.get_counter('/err/nat64-in2out/TCP packets')
+        self.assertEqual(err - tcpn, 1)
+        err = self.statistics.get_counter('/err/nat64-in2out/UDP packets')
+        self.assertEqual(err - udpn, 1)
+        err = self.statistics.get_counter('/err/nat64-in2out/ICMP packets')
+        self.assertEqual(err - icmpn, 1)
+        err = self.statistics.get_counter(
+            '/err/nat64-in2out/good in2out packets processed')
+        self.assertEqual(err - totaln, 3)
+
         # out2in
+        tcpn = self.statistics.get_counter('/err/nat64-out2in/TCP packets')
+        udpn = self.statistics.get_counter('/err/nat64-out2in/UDP packets')
+        icmpn = self.statistics.get_counter('/err/nat64-out2in/ICMP packets')
+        totaln = self.statistics.get_counter(
+            '/err/nat64-out2in/good out2in packets processed')
+
         pkts = self.create_stream_out(self.pg1, dst_ip=self.nat_addr)
         self.pg1.add_stream(pkts)
         self.pg_enable_capture(self.pg_interfaces)
@@ -5023,6 +7038,21 @@ class TestNAT64(MethodHolder):
         ip = IPv6(src=''.join(['64:ff9b::', self.pg1.remote_ip4]))
         self.verify_capture_in_ip6(capture, ip[IPv6].src, self.pg0.remote_ip6)
 
+        err = self.statistics.get_counter('/err/nat64-out2in/TCP packets')
+        self.assertEqual(err - tcpn, 1)
+        err = self.statistics.get_counter('/err/nat64-out2in/UDP packets')
+        self.assertEqual(err - udpn, 1)
+        err = self.statistics.get_counter('/err/nat64-out2in/ICMP packets')
+        self.assertEqual(err - icmpn, 1)
+        err = self.statistics.get_counter(
+            '/err/nat64-out2in/good out2in packets processed')
+        self.assertEqual(err - totaln, 3)
+
+        bibs = self.statistics.get_counter('/nat64/total-bibs')
+        self.assertEqual(bibs[0][0], 3)
+        sessions = self.statistics.get_counter('/nat64/total-sessions')
+        self.assertEqual(sessions[0][0], 3)
+
         # in2out
         pkts = self.create_stream_in_ip6(self.pg0, self.pg1)
         self.pg0.add_stream(pkts)
@@ -5119,7 +7149,7 @@ class TestNAT64(MethodHolder):
 
         self.assertEqual(ses_num_end - ses_num_start, 3)
 
-    @unittest.skipUnless(running_extended_tests(), "part of extended tests")
+    @unittest.skipUnless(running_extended_tests, "part of extended tests")
     def test_session_timeout(self):
         """ NAT64 session timeout """
         self.icmp_id_in = 1234
@@ -5127,7 +7157,7 @@ class TestNAT64(MethodHolder):
                                                 self.nat_addr_n)
         self.vapi.nat64_add_del_interface(self.pg0.sw_if_index)
         self.vapi.nat64_add_del_interface(self.pg1.sw_if_index, is_inside=0)
-        self.vapi.nat64_set_timeouts(icmp=5)
+        self.vapi.nat_set_timeouts(icmp=5, tcp_transitory=5, tcp_established=5)
 
         pkts = self.create_stream_in_ip6(self.pg0, self.pg1)
         self.pg0.add_stream(pkts)
@@ -5139,9 +7169,9 @@ class TestNAT64(MethodHolder):
 
         sleep(15)
 
-        # ICMP session after timeout
+        # ICMP and TCP session after timeout
         ses_num_after_timeout = self.nat64_get_ses_num()
-        self.assertNotEqual(ses_num_before_timeout, ses_num_after_timeout)
+        self.assertEqual(ses_num_before_timeout - ses_num_after_timeout, 2)
 
     def test_icmp_error(self):
         """ NAT64 ICMP Error message translation """
@@ -5149,8 +7179,6 @@ class TestNAT64(MethodHolder):
         self.udp_port_in = 6304
         self.icmp_id_in = 6305
 
-        ses_num_start = self.nat64_get_ses_num()
-
         self.vapi.nat64_add_del_pool_addr_range(self.nat_addr_n,
                                                 self.nat_addr_n)
         self.vapi.nat64_add_del_interface(self.pg0.sw_if_index)
@@ -5193,7 +7221,7 @@ class TestNAT64(MethodHolder):
                 inner = packet[IPerror]
                 self.assertEqual(inner.src, self.pg1.remote_ip4)
                 self.assertEqual(inner.dst, self.nat_addr)
-                self.check_icmp_checksum(packet)
+                self.assert_packet_checksums_valid(packet)
                 if inner.haslayer(TCPerror):
                     self.assertEqual(inner[TCPerror].dport, self.tcp_port_out)
                 elif inner.haslayer(UDPerror):
@@ -5222,7 +7250,7 @@ class TestNAT64(MethodHolder):
                 inner = icmp[IPerror6]
                 self.assertEqual(inner.src, self.pg0.remote_ip6)
                 self.assertEqual(inner.dst, ip.src)
-                self.check_icmpv6_checksum(packet)
+                self.assert_icmpv6_checksum_valid(packet)
                 if inner.haslayer(TCPerror):
                     self.assertEqual(inner[TCPerror].sport, self.tcp_port_in)
                 elif inner.haslayer(UDPerror):
@@ -5284,15 +7312,14 @@ class TestNAT64(MethodHolder):
             try:
                 self.assertEqual(packet[IPv6].src, nat_addr_ip6)
                 self.assertEqual(packet[IPv6].dst, server.ip6)
+                self.assert_packet_checksums_valid(packet)
                 if packet.haslayer(TCP):
                     self.assertNotEqual(packet[TCP].sport, client_tcp_in_port)
                     self.assertEqual(packet[TCP].dport, server_tcp_in_port)
-                    self.check_tcp_checksum(packet)
                     client_tcp_out_port = packet[TCP].sport
                 else:
                     self.assertNotEqual(packet[UDP].sport, client_udp_in_port)
                     self.assertEqual(packet[UDP].dport, server_udp_in_port)
-                    self.check_udp_checksum(packet)
                     client_udp_out_port = packet[UDP].sport
             except:
                 self.logger.error(ppp("Unexpected or invalid packet:", packet))
@@ -5316,14 +7343,13 @@ class TestNAT64(MethodHolder):
             try:
                 self.assertEqual(packet[IPv6].src, nat_addr_ip6)
                 self.assertEqual(packet[IPv6].dst, client.ip6)
+                self.assert_packet_checksums_valid(packet)
                 if packet.haslayer(TCP):
                     self.assertEqual(packet[TCP].sport, server_tcp_out_port)
                     self.assertEqual(packet[TCP].dport, client_tcp_in_port)
-                    self.check_tcp_checksum(packet)
                 else:
                     self.assertEqual(packet[UDP].sport, server_udp_out_port)
                     self.assertEqual(packet[UDP].dport, client_udp_in_port)
-                    self.check_udp_checksum(packet)
             except:
                 self.logger.error(ppp("Unexpected or invalid packet:", packet))
                 raise
@@ -5347,7 +7373,7 @@ class TestNAT64(MethodHolder):
                 inner = icmp[IPerror6]
                 self.assertEqual(inner.src, server.ip6)
                 self.assertEqual(inner.dst, nat_addr_ip6)
-                self.check_icmpv6_checksum(packet)
+                self.assert_packet_checksums_valid(packet)
                 if inner.haslayer(TCPerror):
                     self.assertEqual(inner[TCPerror].sport, server_tcp_in_port)
                     self.assertEqual(inner[TCPerror].dport,
@@ -5469,8 +7495,8 @@ class TestNAT64(MethodHolder):
         try:
             self.assertEqual(packet[IP].src, self.nat_addr)
             self.assertEqual(packet[IP].dst, self.pg1.remote_ip4)
-            self.assertTrue(packet.haslayer(GRE))
-            self.check_ip_checksum(packet)
+            self.assertEqual(packet.haslayer(GRE), 1)
+            self.assert_packet_checksums_valid(packet)
         except:
             self.logger.error(ppp("Unexpected or invalid packet:", packet))
             raise
@@ -5608,8 +7634,7 @@ class TestNAT64(MethodHolder):
             self.assertNotEqual(tcp.sport, 12345)
             external_port = tcp.sport
             self.assertEqual(tcp.dport, 80)
-            self.check_tcp_checksum(p)
-            self.check_ip_checksum(p)
+            self.assert_packet_checksums_valid(p)
         except:
             self.logger.error(ppp("Unexpected or invalid packet:", p))
             raise
@@ -5630,7 +7655,7 @@ class TestNAT64(MethodHolder):
             self.assertEqual(ip.dst, self.pg3.remote_ip6)
             self.assertEqual(tcp.sport, 80)
             self.assertEqual(tcp.dport, 12345)
-            self.check_tcp_checksum(p)
+            self.assert_packet_checksums_valid(p)
         except:
             self.logger.error(ppp("Unexpected or invalid packet:", p))
             raise
@@ -5688,7 +7713,6 @@ class TestNAT64(MethodHolder):
     def test_reass_hairpinning(self):
         """ NAT64 fragments hairpinning """
         data = 'a' * 200
-        client = self.pg0.remote_hosts[0]
         server = self.pg0.remote_hosts[1]
         server_in_port = random.randint(1025, 65535)
         server_out_port = random.randint(1025, 65535)
@@ -5786,7 +7810,7 @@ class TestNAT64(MethodHolder):
         addresses = self.vapi.nat64_pool_addr_dump()
         self.assertEqual(0, len(adresses))
 
-    @unittest.skipUnless(running_extended_tests(), "part of extended tests")
+    @unittest.skipUnless(running_extended_tests, "part of extended tests")
     def test_ipfix_max_bibs_sessions(self):
         """ IPFIX logging maximum session and BIB entries exceeded """
         max_bibs = 1280
@@ -5830,7 +7854,8 @@ class TestNAT64(MethodHolder):
         self.pg0.add_stream(p)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        self.pg1.get_capture(0)
+        self.pg1.assert_nothing_captured()
+        sleep(1)
         self.vapi.cli("ipfix flush")  # FIXME this should be an API call
         capture = self.pg3.get_capture(9)
         ipfix = IPFIXDecoder()
@@ -5857,7 +7882,8 @@ class TestNAT64(MethodHolder):
         self.pg0.add_stream(p)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        self.pg1.get_capture(0)
+        self.pg1.assert_nothing_captured()
+        sleep(1)
         self.vapi.cli("ipfix flush")  # FIXME this should be an API call
         capture = self.pg3.get_capture(1)
         # verify events in data set
@@ -5879,7 +7905,7 @@ class TestNAT64(MethodHolder):
                                                 self.nat_addr_n)
         self.vapi.nat64_add_del_interface(self.pg0.sw_if_index)
         self.vapi.nat64_add_del_interface(self.pg1.sw_if_index, is_inside=0)
-        self.vapi.nat_set_reass(max_frag=0, is_ip6=1)
+        self.vapi.nat_set_reass(max_frag=1, is_ip6=1)
         self.vapi.set_ipfix_exporter(collector_address=self.pg3.remote_ip4n,
                                      src_address=self.pg3.local_ip4n,
                                      path_mtu=512,
@@ -5890,10 +7916,12 @@ class TestNAT64(MethodHolder):
         data = 'a' * 200
         pkts = self.create_stream_frag_ip6(self.pg0, self.pg1.remote_ip4,
                                            self.tcp_port_in, 20, data)
-        self.pg0.add_stream(pkts[-1])
+        pkts.reverse()
+        self.pg0.add_stream(pkts)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        self.pg1.get_capture(0)
+        self.pg1.assert_nothing_captured()
+        sleep(1)
         self.vapi.cli("ipfix flush")  # FIXME this should be an API call
         capture = self.pg3.get_capture(9)
         ipfix = IPFIXDecoder()
@@ -5912,7 +7940,7 @@ class TestNAT64(MethodHolder):
         for p in capture:
             if p.haslayer(Data):
                 data = ipfix.decode_data_set(p.getlayer(Set))
-                self.verify_ipfix_max_fragments_ip6(data, 0,
+                self.verify_ipfix_max_fragments_ip6(data, 1,
                                                     self.pg0.remote_ip6n)
 
     def test_ipfix_bib_ses(self):
@@ -6000,6 +8028,39 @@ class TestNAT64(MethodHolder):
                 else:
                     self.logger.error(ppp("Unexpected or invalid packet: ", p))
 
+    def test_syslog_sess(self):
+        """ Test syslog session creation and deletion """
+        self.tcp_port_in = random.randint(1025, 65535)
+        remote_host_ip6 = self.compose_ip6(self.pg1.remote_ip4,
+                                           '64:ff9b::',
+                                           96)
+
+        self.vapi.nat64_add_del_pool_addr_range(self.nat_addr_n,
+                                                self.nat_addr_n)
+        self.vapi.nat64_add_del_interface(self.pg0.sw_if_index)
+        self.vapi.nat64_add_del_interface(self.pg1.sw_if_index, is_inside=0)
+        self.vapi.syslog_set_filter(SYSLOG_SEVERITY.INFO)
+        self.vapi.syslog_set_sender(self.pg3.remote_ip4n, self.pg3.local_ip4n)
+
+        p = (Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac) /
+             IPv6(src=self.pg0.remote_ip6, dst=remote_host_ip6) /
+             TCP(sport=self.tcp_port_in, dport=self.tcp_external_port))
+        self.pg0.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        p = self.pg1.get_capture(1)
+        self.tcp_port_out = p[0][TCP].sport
+        capture = self.pg3.get_capture(1)
+        self.verify_syslog_sess(capture[0][Raw].load, is_ip6=True)
+
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        self.vapi.nat64_add_del_pool_addr_range(self.nat_addr_n,
+                                                self.nat_addr_n,
+                                                is_add=0)
+        capture = self.pg3.get_capture(1)
+        self.verify_syslog_sess(capture[0][Raw].load, False, True)
+
     def nat64_get_ses_num(self):
         """
         Return number of active NAT64 sessions.
@@ -6016,7 +8077,9 @@ class TestNAT64(MethodHolder):
         self.ipfix_src_port = 4739
         self.ipfix_domain_id = 1
 
-        self.vapi.nat64_set_timeouts()
+        self.vapi.syslog_set_filter(SYSLOG_SEVERITY.EMERG)
+
+        self.vapi.nat_set_timeouts()
 
         interfaces = self.vapi.nat64_interface_dump()
         for intf in interfaces:
@@ -6053,6 +8116,11 @@ class TestNAT64(MethodHolder):
                                            vrf_id=prefix.vrf_id,
                                            is_add=0)
 
+        bibs = self.statistics.get_counter('/nat64/total-bibs')
+        self.assertEqual(bibs[0][0], 0)
+        sessions = self.statistics.get_counter('/nat64/total-sessions')
+        self.assertEqual(sessions[0][0], 0)
+
     def tearDown(self):
         super(TestNAT64, self).tearDown()
         if not self.vpp_dead:
@@ -6076,7 +8144,7 @@ class TestDSlite(MethodHolder):
             cls.nat_addr = '10.0.0.3'
             cls.nat_addr_n = socket.inet_pton(socket.AF_INET, cls.nat_addr)
 
-            cls.create_pg_interfaces(range(2))
+            cls.create_pg_interfaces(range(3))
             cls.pg0.admin_up()
             cls.pg0.config_ip4()
             cls.pg0.resolve_arp()
@@ -6084,13 +8152,41 @@ class TestDSlite(MethodHolder):
             cls.pg1.config_ip6()
             cls.pg1.generate_remote_hosts(2)
             cls.pg1.configure_ipv6_neighbors()
+            cls.pg2.admin_up()
+            cls.pg2.config_ip4()
+            cls.pg2.resolve_arp()
 
         except Exception:
             super(TestDSlite, cls).tearDownClass()
             raise
 
+    def verify_syslog_apmadd(self, data, isaddr, isport, xsaddr, xsport,
+                             sv6enc, proto):
+        message = data.decode('utf-8')
+        try:
+            message = SyslogMessage.parse(message)
+            self.assertEqual(message.severity, SyslogSeverity.info)
+            self.assertEqual(message.appname, 'NAT')
+            self.assertEqual(message.msgid, 'APMADD')
+            sd_params = message.sd.get('napmap')
+            self.assertTrue(sd_params is not None)
+            self.assertEqual(sd_params.get('IATYP'), 'IPv4')
+            self.assertEqual(sd_params.get('ISADDR'), isaddr)
+            self.assertEqual(sd_params.get('ISPORT'), "%d" % isport)
+            self.assertEqual(sd_params.get('XATYP'), 'IPv4')
+            self.assertEqual(sd_params.get('XSADDR'), xsaddr)
+            self.assertEqual(sd_params.get('XSPORT'), "%d" % xsport)
+            self.assertEqual(sd_params.get('PROTO'), "%d" % proto)
+            self.assertTrue(sd_params.get('SSUBIX') is not None)
+            self.assertEqual(sd_params.get('SV6ENC'), sv6enc)
+        except ParseError as e:
+            self.logger.error(e)
+
     def test_dslite(self):
         """ Test DS-Lite """
+        nat_config = self.vapi.nat_show_config()
+        self.assertEqual(0, nat_config.dslite_ce)
+
         self.vapi.dslite_add_del_pool_addr_range(self.nat_addr_n,
                                                  self.nat_addr_n)
         aftr_ip4 = '192.0.0.1'
@@ -6098,6 +8194,7 @@ class TestDSlite(MethodHolder):
         aftr_ip6 = '2001:db8:85a3::8a2e:370:1'
         aftr_ip6_n = socket.inet_pton(socket.AF_INET6, aftr_ip6)
         self.vapi.dslite_set_aftr_addr(aftr_ip6_n, aftr_ip4_n)
+        self.vapi.syslog_set_sender(self.pg2.remote_ip4n, self.pg2.local_ip4n)
 
         # UDP
         p = (Ether(dst=self.pg1.local_mac, src=self.pg1.remote_mac) /
@@ -6114,8 +8211,12 @@ class TestDSlite(MethodHolder):
         self.assertEqual(capture[IP].dst, self.pg0.remote_ip4)
         self.assertNotEqual(capture[UDP].sport, 20000)
         self.assertEqual(capture[UDP].dport, 10000)
-        self.check_ip_checksum(capture)
+        self.assert_packet_checksums_valid(capture)
         out_port = capture[UDP].sport
+        capture = self.pg2.get_capture(1)
+        self.verify_syslog_apmadd(capture[0][Raw].load, '192.168.1.1',
+                                  20000, self.nat_addr, out_port,
+                                  self.pg1.remote_hosts[0].ip6, IP_PROTOS.udp)
 
         p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
              IP(dst=self.nat_addr, src=self.pg0.remote_ip4) /
@@ -6131,7 +8232,7 @@ class TestDSlite(MethodHolder):
         self.assertEqual(capture[IP].dst, '192.168.1.1')
         self.assertEqual(capture[UDP].sport, 10000)
         self.assertEqual(capture[UDP].dport, 20000)
-        self.check_ip_checksum(capture)
+        self.assert_packet_checksums_valid(capture)
 
         # TCP
         p = (Ether(dst=self.pg1.local_mac, src=self.pg1.remote_mac) /
@@ -6148,8 +8249,7 @@ class TestDSlite(MethodHolder):
         self.assertEqual(capture[IP].dst, self.pg0.remote_ip4)
         self.assertNotEqual(capture[TCP].sport, 20001)
         self.assertEqual(capture[TCP].dport, 10001)
-        self.check_ip_checksum(capture)
-        self.check_tcp_checksum(capture)
+        self.assert_packet_checksums_valid(capture)
         out_port = capture[TCP].sport
 
         p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
@@ -6166,8 +8266,7 @@ class TestDSlite(MethodHolder):
         self.assertEqual(capture[IP].dst, '192.168.1.1')
         self.assertEqual(capture[TCP].sport, 10001)
         self.assertEqual(capture[TCP].dport, 20001)
-        self.check_ip_checksum(capture)
-        self.check_tcp_checksum(capture)
+        self.assert_packet_checksums_valid(capture)
 
         # ICMP
         p = (Ether(dst=self.pg1.local_mac, src=self.pg1.remote_mac) /
@@ -6183,8 +8282,7 @@ class TestDSlite(MethodHolder):
         self.assertEqual(capture[IP].src, self.nat_addr)
         self.assertEqual(capture[IP].dst, self.pg0.remote_ip4)
         self.assertNotEqual(capture[ICMP].id, 4000)
-        self.check_ip_checksum(capture)
-        self.check_icmp_checksum(capture)
+        self.assert_packet_checksums_valid(capture)
         out_id = capture[ICMP].id
 
         p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
@@ -6200,8 +8298,7 @@ class TestDSlite(MethodHolder):
         self.assertEqual(capture[IP].src, self.pg0.remote_ip4)
         self.assertEqual(capture[IP].dst, '192.168.1.1')
         self.assertEqual(capture[ICMP].id, 4000)
-        self.check_ip_checksum(capture)
-        self.check_icmp_checksum(capture)
+        self.assert_packet_checksums_valid(capture)
 
         # ping DS-Lite AFTR tunnel endpoint address
         p = (Ether(dst=self.pg1.local_mac, src=self.pg1.remote_mac) /
@@ -6211,12 +8308,16 @@ class TestDSlite(MethodHolder):
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
         capture = self.pg1.get_capture(1)
-        self.assertEqual(1, len(capture))
         capture = capture[0]
         self.assertEqual(capture[IPv6].src, aftr_ip6)
         self.assertEqual(capture[IPv6].dst, self.pg1.remote_hosts[1].ip6)
         self.assertTrue(capture.haslayer(ICMPv6EchoReply))
 
+        b4s = self.statistics.get_counter('/dslite/total-b4s')
+        self.assertEqual(b4s[0][0], 2)
+        sessions = self.statistics.get_counter('/dslite/total-sessions')
+        self.assertEqual(sessions[0][0], 3)
+
     def tearDown(self):
         super(TestDSlite, self).tearDown()
         if not self.vpp_dead:
@@ -6255,6 +8356,9 @@ class TestDSliteCE(MethodHolder):
     def test_dslite_ce(self):
         """ Test DS-Lite CE """
 
+        nat_config = self.vapi.nat_show_config()
+        self.assertEqual(1, nat_config.dslite_ce)
+
         b4_ip4 = '192.0.0.2'
         b4_ip4_n = socket.inet_pton(socket.AF_INET, b4_ip4)
         b4_ip6 = '2001:db8:62aa::375e:f4c1:1'
@@ -6288,7 +8392,7 @@ class TestDSliteCE(MethodHolder):
         self.assertEqual(capture[IP].dst, self.pg1.remote_ip4)
         self.assertEqual(capture[UDP].sport, 10000)
         self.assertEqual(capture[UDP].dport, 20000)
-        self.check_ip_checksum(capture)
+        self.assert_packet_checksums_valid(capture)
 
         # UDP decapsulation
         p = (Ether(dst=self.pg1.local_mac, src=self.pg1.remote_mac) /
@@ -6305,7 +8409,7 @@ class TestDSliteCE(MethodHolder):
         self.assertEqual(capture[IP].dst, self.pg0.remote_ip4)
         self.assertEqual(capture[UDP].sport, 20000)
         self.assertEqual(capture[UDP].dport, 10000)
-        self.check_ip_checksum(capture)
+        self.assert_packet_checksums_valid(capture)
 
         # ping DS-Lite B4 tunnel endpoint address
         p = (Ether(dst=self.pg1.local_mac, src=self.pg1.remote_mac) /
@@ -6315,7 +8419,6 @@ class TestDSliteCE(MethodHolder):
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
         capture = self.pg1.get_capture(1)
-        self.assertEqual(1, len(capture))
         capture = capture[0]
         self.assertEqual(capture[IPv6].src, b4_ip6)
         self.assertEqual(capture[IPv6].dst, self.pg1.remote_hosts[0].ip6)
@@ -6386,12 +8489,7 @@ class TestNAT66(MethodHolder):
             try:
                 self.assertEqual(packet[IPv6].src, self.nat_addr)
                 self.assertEqual(packet[IPv6].dst, self.pg1.remote_ip6)
-                if packet.haslayer(TCP):
-                    self.check_tcp_checksum(packet)
-                elif packet.haslayer(UDP):
-                    self.check_udp_checksum(packet)
-                elif packet.haslayer(ICMPv6EchoRequest):
-                    self.check_icmpv6_checksum(packet)
+                self.assert_packet_checksums_valid(packet)
             except:
                 self.logger.error(ppp("Unexpected or invalid packet:", packet))
                 raise
@@ -6422,12 +8520,7 @@ class TestNAT66(MethodHolder):
             try:
                 self.assertEqual(packet[IPv6].src, self.pg1.remote_ip6)
                 self.assertEqual(packet[IPv6].dst, self.pg0.remote_ip6)
-                if packet.haslayer(TCP):
-                    self.check_tcp_checksum(packet)
-                elif packet.haslayer(UDP):
-                    self.check_udp_checksum(packet)
-                elif packet.haslayer(ICMPv6EchoReply):
-                    self.check_icmpv6_checksum(packet)
+                self.assert_packet_checksums_valid(packet)
             except:
                 self.logger.error(ppp("Unexpected or invalid packet:", packet))
                 raise
@@ -6436,6 +8529,29 @@ class TestNAT66(MethodHolder):
         self.assertEqual(len(sm), 1)
         self.assertEqual(sm[0].total_pkts, 8)
 
+    def test_check_no_translate(self):
+        """ NAT66 translate only when egress interface is outside interface """
+        self.vapi.nat66_add_del_interface(self.pg0.sw_if_index)
+        self.vapi.nat66_add_del_interface(self.pg1.sw_if_index)
+        self.vapi.nat66_add_del_static_mapping(self.pg0.remote_ip6n,
+                                               self.nat_addr_n)
+
+        # in2out
+        p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
+             IPv6(src=self.pg0.remote_ip6, dst=self.pg1.remote_ip6) /
+             UDP())
+        self.pg0.add_stream([p])
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg1.get_capture(1)
+        packet = capture[0]
+        try:
+            self.assertEqual(packet[IPv6].src, self.pg0.remote_ip6)
+            self.assertEqual(packet[IPv6].dst, self.pg1.remote_ip6)
+        except:
+            self.logger.error(ppp("Unexpected or invalid packet:", packet))
+            raise
+
     def clear_nat66(self):
         """
         Clear NAT66 configuration.
@@ -6460,5 +8576,6 @@ class TestNAT66(MethodHolder):
             self.logger.info(self.vapi.cli("show nat66 static mappings"))
             self.clear_nat66()
 
+
 if __name__ == '__main__':
     unittest.main(testRunner=VppTestRunner)