Chapter 10 Install and System Administration for FortiOS 5.0 : Basic Administration : Administrators : Security Precautions : Disable the console interface
  
Disable the console interface
To prevent any unwanted login attempts using the COM communication port, you can disable login connections to the FortiGate unit.
This command is specifically for the COM port. You can still use FortiExplorer to connect and configure the FortiGate unit if required.
To disable an interface:
config system console
set login disable
end
See Also
• Security Precautions
• Passwords
•  
• Disable admin services
• Disable interfaces
• SSH login time out
• Administrator lockout
• Idle time-out
• Administrative ports
• Segregated administrative roles