Changing the server user limit
Simply use a hex editor to replace the first occurrence of "80 f9 1f" with "80 f9 ff" in server.exe. Take a backup in case it goes wrong, so you won't have to reinstall. This sets the limit to 255. Note that servers may lag very much and/or use tremendous amounts of bandwidth when more than a few dozen players are connected.
Source:
http://aceofspadeswiki.com/index.php?ti ... :Bildramer