neither of us have firewall on and i have a built in router :S is it possible to talk to someone on msn or teamspeak about this?

<t> Ive played sp a few times a couple of years ago im back to it today.But the problem is i cant connect to my friends ip.I tried to connect to the ip he was given thru his game.And he tried what the game said was my ip.We cant connect still our games run fine and we have the latest release and ...