Packet Filter On University Network

sachsmachine explains: "I'm a student at a major university where the network admins are thinking of moving to a packet filtering system, one that would block non-university computers from connecting to machines on the student subnets. There will be a meeting to discuss the proposal on Tuesday, but to be fully prepared going in, I'd like to be sure what impacts the move would have. Some of the things that might be broken (depending on what ports get left open) are pretty clear -- remote logins of various sorts, file sharing, Web sharing, instant messaging, Napster and everything else P2P -- but are there any important/unusual/cool/academically useful applications whose ports we should lobby to protect?" By the nature of university (and corporate) rule making, once a policy is in place, it's much harder to dislodge or amend than it might be beforehand. Steve has listed a fair number of applications which could be tossed out by this; how would you suggest saving university bandwidth without losing them all? How would you convince a skeptical audience that remote access is not all of a piece?