You mean how to disable debug mode?
When debug mode is active there are messages printed to the chat bar about hit damage and such and everyone has GM rights...
You cannot really protect or close port 13001 since the game server uses it.
But you can disable debug mode in the CONFIG file by removeing the line "TEST_SERVER=1" (or like this) or using the command "/test_server 0" ingame.
You also can protect your server from API access which is cappable of activating debug mode and do bad stuff with your server.
There are plenty of tutorials here but this is for short:
Add following lines to the CONFIG file:
Code:
adminpage_password=<some random or secret stuff here>
adminpage_ip1=127.0.0.1
You can also patch your game file but therefore you really should read some tutorials...