After searching for an alternative way to play MoW online I managed only to find a few snippets of information, and it's not at all clear if the direct connect feature even works.

Fear not, however, since it still works perfectly and you don't need any additional software to play with your friends.

The host should begin by ensuring the following ports are open. Since every router has a different way of doing this, you're better off checking a guide specifically for your equipment.

TCP
6667
28910
29900
29920

UDP
3210
27900

NOTE: It's likely most of these (probably all the 2xxxx ones) are GameSpy related and not needed. However, I did not test this.

Then, start the game. Inside the Options menu, head to the Multiplayer tab and open the Game IP list. Ask your friends for their IP (it can be found by just typing "my ip" in google) and add it to the list.

In order to connect to your host, you do not need to open any ports. Simply add his IP to the Game IP list and you're done.

Open the LAN server browser and you should be able to see your host in the lobby (and the host should be able to see all the players in the lobby). The host then simply needs to create a game.

Optionally, if you're playing with several people, you can also add their IPs to the list in order to be able to see them in the lobby. However, even if you don't do this, as soon as you all connect to the server you'll be able to see everyone.

And that's it, you're pretty much done.

If you have any issues they are probably related with your port forwarding (it did not work at all for me before I found and forwarded the ports) or something related like anti-virus/firewall software you or your friends may be using.

Cheers, and have fun.