Ok I checked and they do have the same mac address. how do i fix this where i can play system link. Also the games have the same title updates and I have tried other games and still no system link. Thanks for the help Gazcoigne.
LOL stop shareing the same SMC_Config.bin.
Help: there is a option in the advance network called alter mac address, just put a diffrent value that the other xbox but make it the same lenth as every other mac address.