How to configure FortiGate SD-WAN for internet failover in FortiGate firewall

Prerequisite:

-There will be a network downtime needed to configure SD-WAN Failover.

-The 2nd WAN link should be active and connected on the firewall

1. We would need to create SD-WAN Members and we will start with the 2nd link WAN2

Configure SD-WAN Zone

Go to Network > SD-WAN then click create new zone and you can set any name

Create SD-WAN member

For this, we can't usually add the current WAN1 as it is linked to firewall rules. We will have some network downtime at this point to re-route the firewall rules to use the SD-WAN link.

We will start adding WAN2 for the SD-WAN member as it is a new link and not in any rule.

Interface: We will select WAN2

SD-WAN Zone: this is the zone we created for the SD-WAN

Gateway: Dynamic

Cost: 10 - We set this higher as this is the failover link

Priority: 10 - We set this higher as this is the failover link 

To add WAN1 on the member, we will need to modify the firewall rule and point it to SD-WAN. The traffic will be routed to the 2nd link and there will be some network downtime.

Go to Policy & Objects and edit the destination of the firewall rules to use the SD-WAN

After modifying the firewall rules, we can add WAN1 to the SD-WAN member

Create static route going to the internet using the SD-WAN

We will then create a network link monitoring