In your control panel --> Configuration Tab.
You can set a RCON password.
If you did so and restarted your game server to make sure the new rcon password is applied.
You can use tools like BERCon to connect to your game server to administrate it.
Download the attached file and run it.
It will ask you for the IP address, port number and RCON password. All those you can find in your control panel.
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Last updated Thu 8 May 2014