Technical Note: How to use FortiGuard DDNS when FortiGate WAN interface has a private IP address

[cramirez]

Description

This article describes how to use FortiGuard DDNS to resolve to the public IP of the FortiGate when the 'wan' interface is configured with a private IP. The goal is to get management access to a FortiGate using a domain name instead of IP address. 

Scope

FortiGate.

Solution

1. Configure a private IP address on the 'wan' interface.  Note that the FortiGate must be behind a NAT device using a public IP address.
2. Go to System -> DNS and configure the following:
   1. Make sure 'Use FortiGuard Servers' is selected.
   2. Select an interface (wan1 in this example).
   3. Select 'Use Public IP Address'.
      
   4. Select the 'Unique Location', for example, 'fgtest'.
3. Apply.
   
   

To configure in the CLI: 

config system ddns
    edit 1
        set ddns-server FortiGuardDDNS
        set ddns-domain fgtest.fortiddns.com
        set use-public-ip enable
        set monitor-interface wan1
    next
end

After it has been configured, 'fgtest.fortiddns.com' should resolve to the public IP address of the FortiGate.

Related article:
Troubleshooting Tip: DDNS Private IP Issue