X-Git-Url: https://gerrit.fd.io/r/gitweb?a=blobdiff_plain;f=test%2Ftest_nat.py;h=ad2b9649b7de53c5c8d063d6584f935644575154;hb=73710c7da2f8deaea83dbbbfce8737c9c6cd2949;hp=59641a26d5a04730d6762d901c60c1fbc41ebb3b;hpb=d81ae41825f6d276ec778caa2e77a28f66f0ad28;p=vpp.git

diff --git a/test/test_nat.py b/test/test_nat.py
index 59641a26d5a..ad2b9649b7d 100644
--- a/test/test_nat.py
+++ b/test/test_nat.py
@@ -826,6 +826,7 @@ class TestNAT44(MethodHolder):
     @classmethod
     def setUpClass(cls):
         super(TestNAT44, cls).setUpClass()
+        cls.vapi.cli("set log class nat level debug")
 
         try:
             cls.tcp_port_in = 6303
@@ -1302,6 +1303,19 @@ class TestNAT44(MethodHolder):
             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,
@@ -1737,6 +1751,18 @@ class TestNAT44(MethodHolder):
             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"""
@@ -2073,6 +2099,7 @@ 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)
@@ -2556,7 +2583,8 @@ 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()
@@ -2613,7 +2641,8 @@ 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()
@@ -2672,7 +2701,7 @@ class TestNAT44(MethodHolder):
         self.pg2.add_stream(p)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        capture = self.pg1.get_capture(0)
+        self.pg1.assert_nothing_captured()
 
         # remove addresses and verify
         self.nat44_add_address(self.nat_addr, is_add=0)
@@ -2685,7 +2714,7 @@ class TestNAT44(MethodHolder):
         self.pg1.add_stream(p)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        capture = self.pg1.get_capture(0)
+        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,
@@ -2693,7 +2722,7 @@ class TestNAT44(MethodHolder):
         self.pg1.add_stream(p)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        capture = self.pg1.get_capture(0)
+        self.pg1.assert_nothing_captured()
 
     def test_vrf_mode(self):
         """ NAT44 tenant VRF aware address pool mode """
@@ -3091,7 +3120,7 @@ class TestNAT44(MethodHolder):
         self.pg0.add_stream(p)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        capture = self.pg0.get_capture(1)
+        self.pg0.get_capture(1)
 
         p = (Ether(dst=self.pg0.local_mac, src=host.mac) /
              IP(src=host.ip4, dst=server_nat_ip) /
@@ -3582,7 +3611,7 @@ class TestNAT44(MethodHolder):
         self.pg0.add_stream(pkts)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        capture = self.pg1.get_capture(len(pkts))
+        self.pg1.get_capture(len(pkts))
 
         sessions = self.vapi.nat44_user_session_dump(self.pg0.remote_ip4n, 0)
         nsessions = len(sessions)
@@ -3908,6 +3937,20 @@ class TestNAT44(MethodHolder):
             self.logger.error(ppp("Unexpected or invalid packet:", p))
             raise
 
+        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()
@@ -3978,7 +4021,8 @@ class TestNAT44(MethodHolder):
         self.pg0.add_stream(pkts[-1])
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
-        frags = 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()
@@ -4002,7 +4046,14 @@ class TestNAT44(MethodHolder):
 
     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.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)
@@ -4012,60 +4063,61 @@ class TestNAT44(MethodHolder):
 
         self.initiate_tcp_session(self.pg0, self.pg1)
 
-        # close the session from inside
-        try:
-            # 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"))
-            self.pg0.add_stream(p)
-            self.pg_enable_capture(self.pg_interfaces)
-            self.pg_start()
-            self.pg1.get_capture(1)
+        # 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()
+        self.pg1.get_capture(1)
 
-            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"))
-            pkts.append(p)
+        # 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"))
-            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()
-            self.pg0.get_capture(2)
+        self.pg1.add_stream(pkts)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        self.pg0.get_capture(2)
 
-            # 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"))
-            self.pg0.add_stream(p)
-            self.pg_enable_capture(self.pg_interfaces)
-            self.pg_start()
-            self.pg1.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()
+        self.pg1.get_capture(1)
 
-            self.initiate_tcp_session(self.pg0, self.pg1)
-            sessions = self.vapi.nat44_user_session_dump(self.pg0.remote_ip4n,
-                                                         0)
-            self.assertEqual(len(sessions) - start_sessnum, 1)
-        except:
-            self.logger.error("TCP session termination failed")
-            raise
+        sessions = self.vapi.nat44_user_session_dump(self.pg0.remote_ip4n,
+                                                     0)
+        self.assertEqual(len(sessions) - start_sessnum, 0)
 
     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)
@@ -4075,60 +4127,51 @@ class TestNAT44(MethodHolder):
 
         self.initiate_tcp_session(self.pg0, self.pg1)
 
-        # close the session from outside
-        try:
-            # 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"))
-            self.pg1.add_stream(p)
-            self.pg_enable_capture(self.pg_interfaces)
-            self.pg_start()
-            self.pg0.get_capture(1)
-
-            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"))
-            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=100, ack=300))
+        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="FA"))
-            pkts.append(p)
+        # 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))
 
-            self.pg0.add_stream(pkts)
-            self.pg_enable_capture(self.pg_interfaces)
-            self.pg_start()
-            self.pg1.get_capture(2)
+        self.pg0.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        self.pg1.get_capture(1)
 
-            # 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"))
-            self.pg1.add_stream(p)
-            self.pg_enable_capture(self.pg_interfaces)
-            self.pg_start()
-            self.pg0.get_capture(1)
+        # 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()
+        self.pg0.get_capture(1)
 
-            self.initiate_tcp_session(self.pg0, self.pg1)
-            sessions = self.vapi.nat44_user_session_dump(self.pg0.remote_ip4n,
-                                                         0)
-            self.assertEqual(len(sessions) - start_sessnum, 1)
-        except:
-            self.logger.error("TCP session termination failed")
-            raise
+        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.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)
@@ -4138,55 +4181,49 @@ class TestNAT44(MethodHolder):
 
         self.initiate_tcp_session(self.pg0, self.pg1)
 
-        # close the session from inside
-        try:
-            # 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"))
-            self.pg0.add_stream(p)
-            self.pg_enable_capture(self.pg_interfaces)
-            self.pg_start()
-            self.pg1.get_capture(1)
+        # 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()
+        self.pg1.get_capture(1)
 
-            # 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"))
-            self.pg1.add_stream(p)
-            self.pg_enable_capture(self.pg_interfaces)
-            self.pg_start()
-            self.pg0.get_capture(1)
+        # 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"))
-            self.pg0.add_stream(p)
-            self.pg_enable_capture(self.pg_interfaces)
-            self.pg_start()
-            self.pg1.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()
+        self.pg1.get_capture(1)
 
-            # 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"))
-            self.pg1.add_stream(p)
-            self.pg_enable_capture(self.pg_interfaces)
-            self.pg_start()
-            self.pg0.get_capture(1)
+        # 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)
 
-            self.initiate_tcp_session(self.pg0, self.pg1)
-            sessions = self.vapi.nat44_user_session_dump(self.pg0.remote_ip4n,
-                                                         0)
-            self.assertEqual(len(sessions) - start_sessnum, 1)
-        except:
-            self.logger.error("TCP session termination failed")
-            raise
+        sessions = self.vapi.nat44_user_session_dump(self.pg0.remote_ip4n,
+                                                     0)
+        self.assertEqual(len(sessions) - start_sessnum, 0)
 
     def tearDown(self):
         super(TestNAT44, self).tearDown()
@@ -4197,8 +4234,10 @@ class TestNAT44(MethodHolder):
             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.vapi.cli("nat addr-port-assignment-alg default")
             self.clear_nat44()
+            self.vapi.cli("clear logging")
 
 
 class TestNAT44Out2InDPO(MethodHolder):
@@ -4212,6 +4251,7 @@ 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
@@ -4329,6 +4369,7 @@ 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
@@ -5920,7 +5961,8 @@ 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()
@@ -5947,7 +5989,8 @@ 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
@@ -5983,7 +6026,8 @@ class TestNAT64(MethodHolder):
         self.pg0.add_stream(pkts[-1])
         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()