This method works 100% just follow my steps :D
Step 1 Press Windows Key+R and Type "CMD" then press Enter
https://img829.imageshack.us/img829/8378/tifi.png
Step 2 When the window is open Type in "Ipconfig" and press Enter
https://img46.imageshack.us/img46/432/mriq.png
https://img195.imageshack.us/img195/1814/53d.png
https://img27.imageshack.us/img27/6656/7p5.png
Step 3 now copy the IPv4 Adress we will need it
https://img96.imageshack.us/img96/2499/3bk.png
Step 4 open Start and Type in Network
https://img29.imageshack.us/img29/4913/3ep.png
Step 5 press Enter
https://img856.imageshack.us/img856/7720/9bq5.png
Step 6 Press Right Click And then Properties
https://img600.imageshack.us/img600/2959/jw3x.png
https://img12.imageshack.us/img12/2383/vvxh.png
Step 7 Press Settings
https://img593.imageshack.us/img593/5219/u5f.png
Step 8 Press Add
https://img10.imageshack.us/img10/1064/3x6g.png
Step 9 Enter the name you want in Description Of Service EG: Blackops2
https://img707.imageshack.us/img707/5497/hiy.png
Step 10 Paste The IPv4 Adress we copied in step 3 in Name or IP Adress
https://img802.imageshack.us/img802/9004/inyi.png
Step 11 In both fields paste that port "3074"
https://img12.imageshack.us/img12/4489/842c.png
Step 12 Make sure you have UDP selected and not TCP
https://img194.imageshack.us/img194/5071/f8xo.png
Step 13 Now press Ok
https://img94.imageshack.us/img94/3779/djh4.png
Step 14 Just enjoy the game with your friends you Nat type is now open
Credits: ME :D bobo
Press Thanks if i helped you :)