How to route to backup lan interface
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We have 3 offices with VPN connections between every pair. We use OSPF to configure routing. We are adding backup routers with a CARP configuration in each office. Each backup router has OSPF triggering on the CARP IP so it is not active. The VPN connections are also not active until the backup becomes primary.
My question is how can I route from one office to another office's backup firewall's LAN interface?
One thought has been to add a static route to the full internal IP address range (10.0.0.0/8) to the LAN CARP IP - and then perhaps have an OSPF filter to prevent that route from propagating - but I'm a little unsure of how to configure that.
Any other suggestions?
FWIW - I'm not syncing state because the firewalls are not identical hardware (at least at the moment)