I join his game and my player is invisible, i cant move or shoot and a few seconds later i disconnect is it possible for the game to be able to allow friends to join through steam as this would be much easier in my opinion as i am loosing faith using the online servers plus what is the best port to use 1234 is slow.

What you describe sounds same as what we've found a total of 3 people experiencing during the past year. For some unexplicable reason, some players when trying to join one another's game, manage to make the initial connection just fine, the correct map and resources load, but then when the game is to be synced, the client, as far as RWR sees, never receives the chunk of data coming from the hosting computer that would sync the games. We have traced it that the hosting computer does send the data.

A week ago we studied this with one player, but we couldn't pinpoint what it is that makes it happen. He could, for instance, join my game hosted server (Windows) just fine, but he couldn't join my Linux hosted dedicated server. He could join a game hosted server in Germany just fine, but he failed to join SAS Invasion hosted on a Windows based dedicated server in UK. Also he failed to join his friend's game. He himself was from UK. I personally can connect to SAS Invasion just fine, and JackMayol from Germany connects to SAS Invasion just fine. Moreover, JackMayol can connect to both my game hosted server and the Linux server.

We couldn't connect the dots what makes this happen. Based on feedback it's really rare which makes it difficult to understand and investigate. If there are more people out there with this issue, I would really want to hear about it.

Steam wouldn't help with making the data transfer work, that's the game's responsibility, and this issue is somewhere on that layer. Steam would help with sharing the right IP address to connect to, the RWR serverlist does the same thing basically.

Ports are pretty much equal, 1234 is as good as 45678, but the one doing hosting has to have his router set up for UDP port forwarding for the chosen port. It does sound this part is correctly configured in your case, as you are receiving data from the server as your map changes and so on.

Thanks for info my friend is also having the same problem but for some strange reason I can connect to my other friends games as we finished the campaign together hopefully it sorts its self out but I'm more than happy to play single player.