So in my scenario I have the following rough layout:
I’m doing IPSEC Site-to-Site VPN only.
My Local VyOS site has 2 ISPs. ISPA is on eth0, ISPB is on eth1. Static IPs on both.
My Remote Watchguard site has 2 ISPs. ISPA is on eth0, ISPC is on eth1. Static IPs on both.
The Remote Unknown site is a hosted AWS instance from a third-party, they are sending me config information for a single endpoint tunnel.
From my Local VyOS a Site-to-Site IPSEC VPN via ISPA (1 WAN at a time) is easy, but I’m wanting to make the IPSEC tunnel automatically failover to ISPB.
The Watchguard Branch Office VPN does this fairly easy, in their Gateway settings, you just list additional local gateways and remote gateways.
If the failover can be figured out, I assume my second question (Local ISPA to Remote ISPA, failover Local ISPB to Remote ISPA, failover Local ISPB to Remote ISPA, failover Local ISPB to Remote ISPB) will be possible.