I know what you guys are thinking... "FFS! Another idiot that doesn't know how to open his f**king ports!" Well, my NAT is open and my only problem is that every time I restart my XBox, my XBox's local IP changes, so I have to go into my router setting and change it every time I turn on my XBox. This becomes a pain really fast! Is anyone else hving the same problem or have a solution?
The problem you face is probably that your 360 does not have a static IP. On the dashboard, go to System, Network Settings, Edit Settings. Look at "Basic Settings." If the IP settings are set to "Automatic" that is your problem right there. Switch to "Manual" and enter your desired IP address in the appropriate slot. Then, type the router's IP in the "Default Gateway" and type the router's "Subnet Mask" and enter it in the appropriate slot. After you open the ports, run the test, and your NAT should be open.