does graal not work for 2 people playing under a shared network connection?

I have a cable modem under a shared connection, and my friend and I can't see each other talk or move or anything on graal... It kinda works when I check use fixed port for data packages and don't use UDP data packages, but then everyone is jumpy and stuff, and we still can't really do anything with each other...

help?

did u download that 3 party software or whatever?

no... should I? I remmeber trying it long long ago....