Nat settings with x box live
Hey there 
You may find that you have an "Unknown" entry in the list of devices, this will be the Xbox. - Alternatively, there should be an option for "User Defined" - In here, you can manually type the IP address which the Xbox has.
Hope this helps
Matt
You may find that you have an "Unknown" entry in the list of devices, this will be the Xbox. - Alternatively, there should be an option for "User Defined" - In here, you can manually type the IP address which the Xbox has.
Hope this helps
Matt
Is the unknown device there? Are you hard wired to the router or on wireless? There's more questions than answers here 
Really though It sounds like you need to start from scratch, I'm assuming that you already have the the XBox connected to the router but issues with xbox live being the reason you want to DMZ it. Or have you never managed to get connected? Try connecting the xbox with a ethernet cable just for now if you are wireless and set the IP settings to auto. Once you have look at your connection status and see which IP the router has give you. Now you can cross reference that with an ip in the router devices list, the one that matches yours is the Xbox.
If you do all that and it still isn't showing up there must be something wrong router end. I'm not sure how xbox goes about it I don't have one. On the PS3 it tells you information about the connection so if you have that facility post the details of your connection from the xbox and post the devices that are listed on the router. There's a big difference between the xbox being connected but not showing in the list of devices on the router and it not showing up because it actually isn't if you get my drift.
Really though It sounds like you need to start from scratch, I'm assuming that you already have the the XBox connected to the router but issues with xbox live being the reason you want to DMZ it. Or have you never managed to get connected? Try connecting the xbox with a ethernet cable just for now if you are wireless and set the IP settings to auto. Once you have look at your connection status and see which IP the router has give you. Now you can cross reference that with an ip in the router devices list, the one that matches yours is the Xbox.
If you do all that and it still isn't showing up there must be something wrong router end. I'm not sure how xbox goes about it I don't have one. On the PS3 it tells you information about the connection so if you have that facility post the details of your connection from the xbox and post the devices that are listed on the router. There's a big difference between the xbox being connected but not showing in the list of devices on the router and it not showing up because it actually isn't if you get my drift.