I'm trying to solve an issue with a failover setup that I can't get to work properly on my test bench. I'm testing pending deployment. There will also be a backup link between router 1 & 2 installed at some point.

If the link drops between router 1 & 2 I want traffic to revert to the 2 DSL connections on Router 3.

OSPF is set up and working on all devices. OSPF is propagating the default Internet gateway to all devices correctly. Router 1 is set to redistribute as Type 1 but I can't work out how to have traffic route via Router 3 if the link between routers 1 & 2 drops out.

Can anyone give me some suggestions as to how best resolve this?

Saw this didn’t get any sort of reply; figured I’d take a shot if you still are looking for help. What exactly isn’t working? You mentioned BGP but also that default was being redistributed into OSPF. Is BGP only eBGP with upstream providers?

If both router 1 and router 3 are originating default in OSPF and this is all the OSPF backbone area, I would expect the failure of the router1/router2 link to cause traffic to shift traffic towards router 3 after the SPF calculation. What happens when you cut the link? Configs and OSPF state output would be helpful.