Blocking MSN Messenger?
Tekno2k3 asks: "As a sysadmin for a financial company, I have been tasked with removing Instant Messaging from our network. The only service that is being difficult is MSN Messenger. It uses many methods to get around being blocked. These include using port 80, using it's own DNS servers for lookup, using MANY logon servers, and using reverse DNS lookup. Has anyone had any success in blocking Messenger?"
Fire everyone who's caught using it. Eventually you'll fire enough people that they'll be afraid to open it. Just like the RIAA suing P2P users... eventually nobody will share because they'll be afraid of lawsuits.