There's a wealth of this information on the Internet, just plug "firewall block msn messenger" into Google and you'll get tons of hits.
Some stuff I came up with is:
Blocking MSN Messenger is pretty easy, and if you look at my other blocks for this, you will notice that I do a port block and a IP range block. This isn't really needed, but since this can be done, I do. Here are the things you should block to kill MSN Messenger:
· TCP Port 1863
· IP Range 64.4.13.0/24
So on the PIX that would equate to:
> access-list outbound deny tcp any any eq 1863
> access-list outbound deny ip any 64.4.13.0 255.255.255.0
> access-list outbound permit ip any any
> access-group outbound in interface inside
Jay
