dear experts, i'm using ASA 5520 and i want to deny the msn and yahoo messengers without affecting the hotmail or yahoo websites access, so i want to know the specific ports which i should deny and on which transport layer protocols (tcp or udp), i appreciate ur urgent answer because this is very important for me in my security work, thanks alot
I think, you can get the list of port numbers from google.
But you can try the following:
class-map type inspect im match-any yahooandmsn
match protocol msn-im
match protocol yahoo-im
policy-map type inspect im yahoomsn