I work for University and of couse we follow strict policies when it comes to copy write violations namely sharing pirated software on P2P file sharing software. I've had trouble with some users putting Kazaa, bearshare and limewire on computers on my network. Does anyone know if Kazaa,bearshare,napster,limewire and others use a common port to talk to each other? I'd like to block this at the router.

I welcome any experience or suggestions in the matter.