The following article will guide you through the process of password protecting your Host Havoc Garry's mod server.
Step 1: Log into your Host Havoc control panel (https://gamepanel.hosthavoc.com).
Step 2: View your game service.
Step 3: Click on the 'Configuration Files' module.
Step 4: Open the server.cfg file in the text editor.
Step 5: Edit the sv_pasword setting to equal whatever you'd like the password to be.
Step 6: Save the file.
Step 7: Restart the server.
Step 8: To disable the password, set the sv_password setting to be empty ("").