I decided to go for GTA IV for a fiver off Steam the other day and want to play online with a mate of mine but we cant seem to get it to work!! 
I can start a multiplayer game (for example the free roam one) but when I try to invite my mate through the Live invite system he just gets the message "Unable to connect to game session" and I get the same if we do it the other way around!
I've tried opening various ports but there are conflicting views on which ones need to be open!?!?! I know the multiplayer is working OK coz I started a deathmatch game and someone else dropped into the lobby and we started fine!!!!
Any help would be appreciated......
Thanks....
StevieP

I can start a multiplayer game (for example the free roam one) but when I try to invite my mate through the Live invite system he just gets the message "Unable to connect to game session" and I get the same if we do it the other way around!
I've tried opening various ports but there are conflicting views on which ones need to be open!?!?! I know the multiplayer is working OK coz I started a deathmatch game and someone else dropped into the lobby and we started fine!!!!
Any help would be appreciated......
Thanks....
StevieP
I must have done it previously and not changed it back!