Dual ISP

Forum|Forum|4 months ago
December 28, 2025
1 reply
322 views

When i have dual ISP, let say ISP-A and ISP-B then which ISP will be used for forti DDNS source?

FortiGate

AEK

SuperUser

The interface is selected in the DDNS config, as show in the tech tip.

https://community.fortinet.com/t5/FortiGate/Technical-Tip-How-to-configure-Dynamic-DNS-FortiGate/ta-p/208780

AEK

HS08Author

Visitor III

Example I set ISP-A and ISP-B on the interface, then forti ddns will use ISP-A and if ISP-A down then the record will use public ip from ISP-B?

Toshi_Esumi

SuperUser

As the KB @AEK referred, you have to specify a unique name for each interface/ISP, like "isp-a.fortiddns.com" and "isp-b.fortiddns.com", which can be used to set up like IPsec or other VPN connection from outside.
In other words, both are up unless you configured for the secondary to be down while the primary is up.

Toshi

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