Although you can block the default ports for each of these programs they all have the ability to easily be reconfigured to use any available port if the default is unavailable. For some it is an automatic process others it is in the preferences. You may be successful in blocking newbies but those who have used any of these programs for a while will be able to easily get by. Blocking by IP is possible but, is a real pain as you will have to find all of the possible IP addresses for each service and constantly monitor as the networks for these services are constantly growing and new addresses appear all the time. I personally wouldn't recommend it.
Wish there was an easy answer for you but, there just isn't.
I agree with you. It's very hard to block this kind of stuff. I strongly recommend that you contact your personnel (the guys who are in charge of newtork servers e workstations support) to avoid giving admin rights to users on windows workstations and stuff like that (using SMS, ZENworks, for example). This action will stop any unwanted software installation on those machines.
Also I was wondering if a firewall with content-inspection would block this issues (by using keywords like "napster", "morpheus", "mp3" and others).
Is NBAR going to be any good for you? We've tried it before, and it seemed to work really well just counting napster packets, but we didn't try and block any. You'll have to get the napster PDLM though.
Table of ContentsIntroductionVersion HistoryPossible Future
UpdatesDocuments PurposeNAT Operation in ASA 8.3+ SectionsRule Types
Network Object NATTwice NAT / Manual NATRule Types used per SectionNAT
Types used with Twice NAT / Manual NAT and Network Obje...
Table of Contents Introduction:This document describes details on how
NAT-T works. Background: ESP encrypts all critical information,
encapsulating the entire inner TCP/UDP datagram within an ESP header.
ESP is an IP protocol in the same sense that TCP an...