How do I fix the NAT type for xbox live/ Black ops?

You have to call your internet provider and they will walk you through it. Sometimes though it can turn from moderate to strict due to a power surge. Just take out the power source for your router and wait 10 seconds and then put it back in. Once it boots up see if its fixes. Hope this helped!

go to the network settings and select the first option to configure network. write down your xbox's IP address. then go to your PC and access your routers configuration page. (it like a website). find DMZ settings and turn it on and in the area to insert the IP address, type in the address from the xbox and you shouldnt have a problem ever again. NOTE: with some routers, if they lose power all together, you may have to go back in and enter this again. ALSO NOTE: your xbox's IP address will most likely be different sodo it all over again.

if you know your routers IP address theres a website for the numbers you enter into the address bar on you computer for google. you can then go there and open a special port that allows you to have you NAT type open. If you don't know your IP adress go to the dashboard of your 360 go to system settings. this happend to me and it took the longest time to fix. I hope i kinda helped..