cd ${ROOTDIR}/nsh_sfc_tests/sfc_scripts/
sudo rm -f temp_packet.pcap
-sudo tcpdump -i $1 -c 1 -w temp_packet.pcap dst host $2 >/dev/null 2>&1 &
+sudo /usr/sbin/tcpdump -i $1 -c 1 -w temp_packet.pcap dst host $2 &
+
+if [ ! $? -eq 0 ]; then
+ echo "Start the tcpdump failed!!!"
+ exit 1
+fi
cd ${PWDDIR}