Configuring DynDNS on Fortigate FortiOS 5.0 and 5.2 in CLI Mode

The only way available to configure DynDNS or other providers in Fortigate 5 and 5.2 OS is by command line.
1) Connect to the device by telnet or SSH or GUI terminal and type the following command.

config system ddns  
edit 1      
set monitor-interface "wan1"        
set ddns-server dyndns.org        
set ddns-domain "hostname"        
set ddns-username "username"        
set ddns-password password

* edit 1 – 1 is the index number of DDNS settings. Start with 1 if its the first DDNS settings on the Fortigate box. This index number should be used later to modify anything related to this settings if required.
* wan1– is the port you need to configure DDNS and obviously connected to internet.
* ddns-server – dyndns.org is the server of DynDNS service provider. For other providers, see more detail below.
* hostname – is the one you have registered at dynamic DNS provider.
* username – user name of corresponding hostname at the provider.
* password – for the username and hostname from the provider.
The following DDNS servers can be used to configure Dynamic DNS in FortiOS 5 and later.

dhs.org — supports members.dhs.org and dnsalias.com.
dipdns.net — supports dipdnsserver.dipdns.com.
dyndns.org — supports members.dyndns.org.
dyns.net — supports www.dyns.net.
easydns.com — supports members.easydns.com.
FortiGuardDDNS — supports FortiGuard DDNS service.
genericDDNS — supports DDNS server (RFC 2136) defined in ddns-server-ip.
now.net.cn — supports ip.todayisp.com.
ods.org — supports ods.org.
tzo.com — supports rh.tzo.com.
vavic.com — supports ph001.oray.net.

Once you have configured DynDNS service as shown above, the WAN port of the device will be monitored and changed accordingly with the name and IP.

2) Typing,

show system ddns

will shows the ddns settings of the Fortigate device in CLI which can’t be seen in GUI mode.

3) To edit the same ddns entry, you can use

config system ddns  
edit 1

Make sure to enter correct index number ( eg 1) to modify.

It is recommended to take backup of the device configuration, so you can use it in future or while replacing the existing device. By using backup you do not need to configure dyndns again via CLI.