Using nc (netcat) to emulate NTP server response

Question

I want to test some security on an NTP client developed in-house and would like to use netcat to do it. I have packets captured with Wireshark from previous NTP exchanges that I tried to feed to the client but that doesn't appear to be working.

Answer 1

Perhaps these tools can help you:

PlayCap
Playback for Wireshark Captures

Tcpreplay

Answer 2

Here is another great tool:
Ostinato, packet crafter and traffic generator