Loopback Address at SD-WAN

The SD-WAN itself shouldn't require a loopback interface/address on a FGT. But if you have set up two FGTs connected together over multiple VPNs and you put the multiple VPNs in an SD-WAN zone, you might want to set up a common interface/IP on the remote end to ping to with a performance SLA health-check rules so that the local end can measure which path/VPN is the best at a time in order to prefer that path.

My home FGT has SD-WAN for internet traffic steered but no VPNs to the other FGT is a member of a zone. So I don't have/need any loopback interface.

Toshi