I have a problem with partying up with friends to play Gears of War 3. I can join random games without issue, sometimes I am even designated as the host and there is no problem at all.
I however cannot invite people to games where people have left, or host or join other peoples private games.
My NAT is OPEN, and I have tried port forwarding (which actually makes my nat go from OPEN to MODERATE) and port triggering (which does nothing).
Ports used following this guide http://support.xbox.com/en-US/xbox-live/troubleshoot/connection-issues/nat-type-strict
The only problem I can see is that when I test my Xbox connection right now, it goes through fine (NO NAT ISSUE) but has an error status report
W: 0000 - 000B
X: 0000 - F001
Y: 20A8 - 4840
Z: 0000 - 0000
ID: FFFF - FFFF
My router is a Netgear WNDR3700v2