ZDoom

It almost sounds like the fault isn't zdoom, but something else interfering (like some shitty firewall or something).

I walked him through to allow port 5029 UDP on his router, and we're just basically doing gzdoom.exe -host 2 (or gzdoom.exe -join [IP])... we both tried interchangably hosting and joining, both didn't work...

5029 UDP pinhole'd though your router, and allowed on what ever kind of firewall you may or may not have. If it's still not working, you will have to tell us exactly how you are trying to play multiplayer.

Nash and I were trying to test out GZDoom multiplayer over the internet (not LAN), and he said that he tried it with someone else and it worked, but when I tried it, it just kinda hung at the "finding host" step. I added an exception to the Windows firewall, and even the firewall on my router, but still no luck. How do I fix this?