Network tester passes, can't host or join games.

[Pellucid]

So I used to have my ports closed and consequently could only join other peoples' games in Automatch. I decided I'd like to be able to host games so I took all the steps in here, opened my ports, ran the network tester with all passes and no NAT detected, and now not only can I not host games, I also can't join them either. Windows firewall is off, I have a pretty good Linksys router that works just fine for every other game I play, and I have no idea what could possibly be the problem. Can anyone help me?

[GroundZero]

Which Linksys Router do you have??

[Pellucid]

I believe it's this one: http://www.amazon.com/Linksys-WRT54G-Wireless-G-Router/dp/B00007KDVI

I tried putting myself in the DMZ on the router and that worked, but I'd really like to have a solution that doesn't completely expose my computer to internet threats. :nyah: