Firewalling Q

[Schizik]

Greetings, gurus!

I do need to limit people from my internal LAN to access
filesharing services like eDonkey, Mule, Kaza, etc

The problem is that it is can not be done with port ranges
based ipfw rules, because ports can be changed by users
in this programs.

What is I need some sort of setup which will analyze traffic
going to and from people and based on recognition apply
different firewall rules.

Can anyone recommend me an approach for this?


Alex.