netsed - 1.2-3 main

NetSED is a small and handy utility designed to alter, in real time,
the contents of packets forwarded through your network. It is really
useful for network packet alteration, forging, or manipulation.
NetSED supports:
.
* black-box protocol auditing - whenever there are two or more
proprietary boxes communicating using some undocumented protocol.
By enforcing changes in ongoing transmissions, you will be able
to test if the examined application can be claimed secure;
* fuzz generating experiments, integrity tests - whenever you do
stability tests of an application to see how it cares for data
integrity;
* other common use-cases: deceptive transfers, content filtering,
protocol conversion - whatever best fits your task at hand.
.
It ideally complements a tool suite based on ngrep, netcat, and tcpdump.