I was just fiddling around trying to open my NAT, and now my console won't connect to Live anymore. I use the wireless device. IP, DNS etc - everything is confirmed, but when it gets to Xbox Live it fails.
During the fiddling, I checked the DMZ box and entered my consoles IP as the DMZ IP. I tried switching on UPnP - and had them both on at the same time at one point (which is apparently not good) - and now it fails to connect.
I can't remember the IP that was previously in the DMZ, but I have tried unchecking the box and have had no luck... any help anyone can give me would be much appreciated. Until now it has always been working fine (although, annoyingly, with a strict NAT) - so it's presumably something I've done wrong.