How do I play COD 4 with my friend at a different house?

Solution 1:

You can join online servers in "Join Game" and "Internet" section, and also you can use online parties like Garena or Gameranger. you can also host your own server so you can play 1v1 on free.war24.net/create/cod4. you can also create a server on a web host if you host one.