said by DaveX510 :
Ya both xboxs need ports 3074 etc
Actually if your router is using UPnP then only the 1st one turned on needs 3074, the 2nd one will get another port, the details of the port selection the Xbox'es use is not listed in a doc.
thus if you want multiple Xboxes to all be open-nat then you sadly have to use UPnP.--
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