We're excited to announce that we've fully migrated the Xbox Forums to their new home, here on the Microsoft Community forums!
As of today, going to forums.xbox.com will redirect you here to the Xbox area of the Community forums. We've moved all of your existing threads over so you can continue and start conversations with the new forums experience.
We sincerely appreciate the feedback you have provided over this transition and can't wait for you to check out the new Xbox Forums!
It's working OK for me, though last night my friend's game freaked out and dumped him to the Home screen while we were setting up the game. Restarting the Xbox fixed it.
One thing we noticed was that the Xbox One labeled both of our routers as "strict" (Settings -> Network). We both have Xbox 360s as well, and those always showed "open". Well, the issue is that the Xbox One and the Xbox 360 both use the same ports (The Xbox
One uses a couple of extra ones that the 360 didn't) so if your router is set up to forward the ports to the Xbox 360's IP address, then those ports are effectively closed for the Xbox One. Hence you get a "strict" NAT, which can cause issues with matchmaking
The Xbox One also doesn't use UPnP correctly (which would automatically configure the ports for you), so unfortunately the fix is that you have to go into your router's configuration and manually forward the ports to the Xbox One IP address. This also requires
that you give the Xbox One a fixed IP address instead of using DHCP.
There are more details about testing/fixing NAT issues