Here is the new firewall at the school. It is running OpenBSD 3.6 and has no ip addresses at all. Completely transparent. When I get the rules set up on it, there will be no way around it because it sits between the router and the bridgehead switch.
Here are the specs:
Digital 3000 PC
Intel Pentium I MMX 200mHz
96 megs of ram
2 gig hard drive
2 DEC 10/100 network adapters