Chapter 10 Install and System Administration for FortiOS 5.0 : Basic Administration : General Settings : Administrative port settings
  
Administrative port settings
The Administrative Settings enable you to change the default port configurations for administrative connections to the FortiGate unit for added security. When connecting to the FortiGate unit when the port has changed, the port must be included, such as https://<ip_address>:<port>. For example, if you are connecting to the FortiGate unit using port 99, the url would be https://192.168.1.99:99.
If you make a change to the default port number for HTTP, HTTPS, Telnet, or SSH, ensure that the port number is unique.
See Also
Administrative port settings
Administrator configuration
Administrator profiles
Adding administrators
Administrative port settings