My university has an all encompassing computer account system, meaning our computer accounts, email accounts, and VPN authentication (i think) all have the same username and password.

The problem comes from what I think is the vpn authentication. To go on the internet using the university's network, one must supply their username and password somehow. Basically this involves opening up firefox, and a window appears prompting for your login info. However, this username and password is sent in plain text.

The campus networks are wireless and, I believe, unswitched. They may be switched, but in any case I am receiving traffic from other computers. This poses a couple of problems.

1) Sometimes (not always, it is very strange), I receive shitloads of traffic, causing my own connection to slow to a crawl.
2) I can open up wireshark or ettercap and see what everyone is doing. I can also get their school user name and pasword this way, and thus have access to their email accounts and lab computer accounts.

As you can see, this is frighteningly retarded. First of all, how do I stop my own network interface by being flooded with other people's traffic? Second of all, how do I prevent other people from monitoring me and getting my username and password?

EDIT: If it makes any difference I'm running Linux/GNU

Get as many usernames/passwords as you can

Post them on a very public website from a completely anonymous computer.

Your institution will change its policies shortly.

That isn't VPN.

Your uni is very lax.

All of our shit is extremely well hidden/encrypted/locked down.

IT is in one building (where we get our shit fixed), while all the servers and computers that run the campus are stored behind a triple lock bullet proof door that only 5 individuals including the president have access to. If you need to talk to the network administrator (his office is behind the glass), you need to stand at the door, use the mounted phone to call the secretary who will have him come and talk to you through the glass.