tcpreplay and timestamps

Question

I want to use tcpreplay to replay a packet trace made of TCP and UPD packets.

Is there a way to attach a timestamp to each outgoing packet, so that I will be able to compute the round trip time once all replies have been received (and dumped)?

Otherwise, which other tool should I use?

Answer 1

If you sniff traffic at the same time with tcpdump or Wireshark, it will timestamp each packet on the way out and the replies.

Just a warning though, tcpreplay generally doesn't support replaying TCP streams to servers since it doesn't track state of the TCP stream. Generally all you'll get are Reset packets in reply. UDP should generally be ok. ICMP often works. If you want more information, be sure to check out the Tcpreplay FAQ:

http://tcpreplay.synfin.net/wiki/FAQ#Doestcpreplaysupportsendingtraffictoaserver