Technical Tip: How to update changing dynamic IP when using third-party DDNS service

[sjoshi]

Description

This article describes how to monitor WAN interface of the device and update the changing IP address accordingly with the domain name when using third-party DDNS service.

Scope

FortiOS.

Solution

When Dynamic IP that is provided by ISP changes frequently it will be difficult to keep in track for the incoming connection.

Using FortiGate DDNS service, and register a domain name from the DDNS provider to link the Dynamic Changing IP with a unique  fully qualified domain names (FQDN).
Whenever there is an IP change in WAN interface, FortiGate will automatically notify DDNS service provider to update the IP address with the unique fully qualified domain names (FQDN).

In this article, DynDNS DDNS will be used on FortiGate.

The configuration part: 

config system ddns
    edit 1
        set ddns-server dyndns.org <--- Select a DDNS service provider
        set ddns-domain "fortinet" <--- The domain name assigned for this FortiGate which has been configured in DDNS Server( So the full FQDN will be fortinet.dyndns.org)
        set ddns-username "admin" <--- DDNS user name provided by DDNS provider for the domain
        set ddns-password admin@123 <--- DDNS password provided by DDNS provider for the domain
        set update-interval 60 <--- DDNS update interval
        set monitor-interface "port1"  <--- Monitored interface name
    end

After configuring DynDNS in FortiGate, the WAN interface of the device will be monitored and change accordingly with the domain-name and IP address.
If there is any IP change in WAN interface then FortiGate will notify the DDNS provider to update accordingly to the IP address currently received on WAN interface.

Select the correct WAN interface under DDNS settings in set monitor-interface !

Supported providers:

( options in set ddns-server , listing sample from FortiOS 7.2.8 - 2024.05):

dyndns.org	members.dyndns.org and dnsalias.com
Option	Comment
dyns.net	www.dyns.net
tzo.com	rh.tzo.com
vavic.com	Peanut Hull
dipdns.net	dipdnsserver.dipdns.com
now.net.cn	ip.todayisp.com
dhs.org	members.dhs.org
easydns.com	members.easydns.com
genericDDNS	Generic DDNS based on RFC2136.
FortiGuardDDNS	FortiGuard DDNS service.
noip.com	dynupdate.no-ip.com