Good network analyzer

[mancombseepgood]

Does anyone know of a good (free?) network analyzer?
I have had a look at eEye's iris and it is fab but costly. I'm not looking for a packet capture interface - those are common, I want one that can reconstruct the packets from a source as iris can...
Thanks in advance!

 

[gregmcc]

have you tried packer player
http://www.colasoft.com/packet_player/