- Primary ISP - fiber
- Backup ISP - DSL
We have various apps/services like VPN, email, etc. that come in on various external IPs on the primary ISP.
Is there a way without BGP peering to have a way to allow failover of incoming services like the above?
For email I can't use secondary MX records, as we use a cloud service for email scrubbing and then email is sent to an external host record from them.
I don't think there's a way to create multiple Host A records with varying metrics, but that would be the logic I'm looking for. Something that says "vpn.domain.com resolves to 220.127.116.11 but that isn't responding so fail back to 18.104.22.168". Obviously, the complication is how does the app/service really know that 22.214.171.124 isn't responding.
Anyone figure out solutions to failover incoming apps/services between ISPs?