Occurs on latest dev build (Beta)
For some users (as reported here http://forums.bistudio.com/showthread.php?147537-Tutorial-How-to-run-ArmA3-on-a-dedicated-server&p=2422167&viewfull=1#post2422167) arma3server.exe fails to listen on steam ports. This means that clients cannot connect to the server.
This occurs when the steam client is running and the arma3server.exe is launched.
If the arma3server.exe is launched prior to the steam client, the server initializes correctly.
This occurs regardless of the steam port configuration in the server.cfg.
Note that the issue does not occur with arma3.exe -server.