Instant Messenger's ports - to block

AOL Instant Messenger



Prevent File Transfers: TCP 5190

IM images - TCP 4443
Disable all together - block login.oscar.aol.com on ALL ports.



MSN



Prevent File Transfers, disable incoming/outgoing TCP 6891
Prevent Audio/Video conferencing, block UDP 13324 and 13325
Prevent Application sharing block TCP 1503
Disable altogether deny access to hosts in the msgr.hotmail.com sub domain and block TCP 1863

ICQ

Prevent file transfers, block TCP 3574
Disable file sharing images, block TCP 7320
Disable ICQ completely, deny access to loign.icq.com on TCP 5190

Yahoo

Block Instant Messaging, block TCP port 5050
Block Yahoo Messenger completely, deny access to hosts in the *msg.*.yahoo.com sub domain



KaZaA



Block TCP sessions on port 1214



eDonkey



4661 TCP to connect with a server
4662 TCP to connect with other clients
4665 UDP to communicate with servers other than the "Main" server the client is connected to.
4663 TCP is used with the command line client when it is configured to allow remote connections.