1. go to run > cmd > ipconfig /all get your default gateway
2. put your default gateway in your URL (internet browser)
3. Hop on your console and assign it a Static IP if its not already..
4. Get back onto the computer and login to your router.
5. Find DMZ It's usually under tools: and put in the IP.. Then click enable/allow
You NAT is now open.
Im too lazy to upload pictures, and this tutorial should be easy enough to follow.