Question:

We have a 2920n and want to know how to achieve failover order of:
WAN 2 (Primary WAN)
WAN 1 (Backup WAN #1)
WAN 3 (Backup WAN #2)

So when WAN 2 disconnects it tries to use WAN 1 and if it can’t get WAN 1 then it uses WAN 3.

Solution:

Set up WAN 1 and WAN 2 to be Always On (with WAN 3 listed at the Backup WAN for each).
Set WAN 3 to be a backup WAN with “When all WANs disconnect”.

Then set up a load balancing rule that says all traffic use WAN 2 and also enabled (ticked) “failover to use other WANs” in the rule.

So now traffic gets routed using WAN 2 but if the fails the load balancing rule then uses the other available WANs.

Then if both WAN 1 and 2 disconnect then WAN 3 connects.