recently my friend came over to my house and we were going to set up both 360s so we wouldnt have to split screen. my xbox was connected directly to the router via ethernet cable. since we didnt have a cable long enough to go from the router to the other tv, this is what i did. i hooked his xbox to my computer, which connects wirelessly and has a shared connection, and it worked. but when we tried to join each others parties, we couldnt. we both could get into matchmaking fine but couldnt get into each others parties. the error massge was saying something about my NAT not being opened but i could not figure out how to open it. and im not even sure if the NAT thing was the problem.