Blocking Windows Live Messenger Usage in a corporate or home site.

Windows Live Messenger is an updated version of MSN Messenger and uses similar ports. It seems that Windows Live Messenger uses:

Messenger server: port 1493, 1542, 1863, 1963, 80 TCP and 443 TCP
File Transfer/Sharing Folders: local: 1544 and 6891 – in fact 6720-65535 TCP from one source
Messenger Update: remote: 80 local: 1457
Remote Assistance If available): 3389 TCP
Audio: local: , 1556, 11771, 13803 and generally 5004-65535 UDP
Remote Desktop and whiteboard: local/remote: 389, 522, 1503, 1720, and 1731
Launching Games: 80
Video Conference: TCP 9000-9999, 5004-65535 UDP + 80
Sign-In: remote: 443 local: 1484, 2400

Note – blocking TCP port 80 will stop users accessing web sites using Internet Explorer and other browsers.