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DDNS updates on second WAN interface

Hi All,


We have dual WAN setup with primary being an MPLS tail (WAN1) and the secondary being a 4G/LTE connection (say WAN2 - via FortiExtender) which is used for failover.


To keep both in routing table, default route is maintained for both with identical distance ->  lower priority is assigned to WAN1. This allows us remote access to both interface via both with WAN1 being used unless it drops.


As the 4G uses PPPoE, the IP assigned is dynamic and we've setup a corresponding DDNS entry using inbuilt FortiDDNS.


I've noticed the fortiddns DNS value doesn't seem to update when both interfaces are up, reflected in log entry 'DDNS update domain=xxxx on FortiGuardDDNS failed'


I'm guessing it because of the routing.  ie when both interfaces are up, the device is still trying to send the update OUT the WAN2 interface rather than just querying the IP of that interface (as per the monitor-interface setting).


Any ideas or workarounds?   Or would a 3rd party provider look at the interface IP specified (WAN2), and successfully send the update out WAN1 as per the routing table?









with both ports being up, shouldn't sending out wan2 succeed? The FGT will definitely expect the reply on wan2 as well.

Have you checked that the 4G WAN address is public and not private?


I once had issues with DDNS against until I realized that the 'domain' field needed to be the FQDN, i.e. '' and not just 'host'...

Ede Kernel panic: Aiee, killing interrupt handler!
Ede Kernel panic: Aiee, killing interrupt handler!

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