can ping both box's. on same lan and sub net. game starts it see the other game profile name then when you join comes back and says game no longer in session. tried 2 differnet games hosted and joined both ways

Some games suffer this issue if both boxes are not running the game from the same media. For instance:

The game Timesplitters 2, while attempting to system link can lose connection if xbox A is running the game from disc and xbox B is running the game from the hard drive. The player running the game from the disc typically gets kicked immediately after a system link match starts. I believe this is due to xbox B loading the game faster (from the HD) than xbox A.


I dunno if this is your problem but this is the first idea that popped into my head for some reason.