What is the Best Firewall for Servers?

Sushant Bhatia asks: "I maintain a bunch of servers (Win 2003/XP Pro) at our labs in the university. Of late, the number of attacks on the computers has been more noticeable. The university provides firewall software (Kerio) but that doesn't work with Win 2003 (works with XP). And so we keep getting hit by zombie machines taken over in the Education Department or from Liberal Arts :-). So what does the Slashdot crowd use when they need to secure their Linux and Windows servers? Does it cost less than US$100?"

Comments

Re:at the risk of getting flamed into submission..

[nocomment]

I have an OpenBSD router here at work that I built, and I will vouch for it's performance. We have been hit by Drudge and /. a few times, and even though none of the websites or mail servers would work I was able to poke around in the firewall with no noticable lag. We had over 10,000 ACTIVE states in the table, and the performance of the server was pretty stable with no noticalbe lag on the console (couldn't ssh as the T1's were all maxed).

System specs are pretty normal, 1Ghz Athlon with 512MB RAM.