> Nope, the protocols are reverse engineered and people create their own server software.
Which is one of two reasons (the other being anti-cheating) that newer games withhold a large part of the game logic on the server side. It is possible to reverse engineer game logic but impractical: you might as well rewrite the game.
If you have a look at efforts to reverse engineer Diablo 3, you'll see that most of the game is missing without the server. You can run around but you can't do anything.
Which is one of two reasons (the other being anti-cheating) that newer games withhold a large part of the game logic on the server side. It is possible to reverse engineer game logic but impractical: you might as well rewrite the game.
If you have a look at efforts to reverse engineer Diablo 3, you'll see that most of the game is missing without the server. You can run around but you can't do anything.