Replay traffic captured using tcpreplay

0
votes

We have PCAP dump which has TCP packets. These packets are captured on a network interface.

Now i want to replay these packets from my "Server A" ----> "Server B". The server "A" and server "B" are in local LAN network and there is a switch in between.

Server A   <-------Switch-----> Server B

To send traffic from "A" to "B", we have changed the dst Ip and dst MAC of the packets in PCAP file to dst IP and dst MAC of server B.

Below is the command used

tcprewrite --infile=udp_lite_full_coverage_0.pcap --outfile=test_2.pcap --dstipmap=0.0.0.0/0:10.76.110.84/26 --enet-dmac=34:17:EB:AF:7E:EA

Then we replayed the traffic from server "A" eth0 using below command 

sudo tcpreplay --loop=0 --intf1=eth0 test_2.pcap

Eth0 of "B" is reachable from "B".

With the above i expect the packets to be seen at eth0 of server "B". But i am not seeing any packet at server B. Can you please help me in fixing this issue.

Thanks

1
networkingtcpnetwork-traffictcpreplay

1 Answers

0
votes

You cannot replay previously recorded traffic into a TCP server. TCP servers issue a random sequence number during 3-way handshake. Replayed traffic will be using a different starting sequence number, which the server will reject it.

UDP works, TCP doesn't.