Sniffit is a network sniffer for TCP/UDP/ICMP packets.

Sniffit produces very detailed technical details about the packets flowing
through your network (SEQ, ACK, TTL, Window, ...) and also packet contents
in different formats (hex or plain text, ...)

WWW-404: http://reptile.rug.ac.be/~coder/sniffit/sniffit.html
FAQ-404: http://reptile.rug.ac.be/~coder/sniffit/sniffit-FAQ.html
     or  http://reptile.rug.ac.be/~wvdputte/sniffit_addicts_anonymous/