I am trying to setup a rule on our ISA 2006 server to block Windows Live Messenger.
I have been able to setup the Deny MSN Messenger rule on ports 1863 & 443 and I can see when monitoring my IP connection that it is identifying these and blocking them at this point - however once this deny rule runs it proceeds to connect using an HTTP Proxy connection.
I have followed instructions in http://support.microsoft.com/kb/925120
and setup a block msn rule (which doesn't seem to have any effect).
I have filtered through sites and found a list of Signatures for different versions of Messenger - added those to the configure HTTP rule - however still no luck.
Any help on blocking the current MSN/Live Messenger using ISA 2006 server level would be fantastic.
I see a similar question on https://www.experts-exchange.com/Microsoft/Windows_Security/Q_24513167.html
however it doesn't seem to have an answer.