To anyone looking for this page. I noticed that some people had searched for my tcpdfilter program as recent as 2007. I had assumed that fresh meat would keep it around forever, so I just left it there, and forgot about it. Seeing it is now gone, I got to thinking, and it's possible there's people out there that might have really old systems that they still need to support, via network debugging of some sort. If you have a more recent system, tcpdump will output hex and ascii, if that's all you need. Or, if you need packet decoding capability then ethereal or wireshark may be better choices for you. Still kicking myself for not making a GUI packet decoder like ethereal. ethereal came out relatively shortly after I wrote tcpdfilter. 😛
So, if you are still looking for it, let me know, and I can scrounge up the source for you. I do have it on my system.