Is there a way to block MSN Messanger through an Airport Extreme Base Station? I have a teacher-friend who is having problems with students using their personal laptops to instant message through MSN Messanger during class. The school does not block IM, its actually used by alot of the administration offices to communicate between each other. Any idea on what port MSN uses? The school's IT guy (yes guy, not a department) has no idea on how to block it for just one classroom. The airport base station is hers, personally, and is connected directly to the school's ethernet network.