Here you can get the steps to find the Mac Address on New Xbox 360
Step 1 :
In the Xbox Dashboard go to My Xbox and further select System Settings.
Click Network Settings and then Configure Network.
Go to Additional Settings tab and select Advanced Settings from that , then next select Alternate Mac Address.
You will see title called Wired MAC below this screen.
Alright now you get connect. Enter your queries about the connection in bellow comment box.