border routers shouldn't announce default route into OSPF unless they have external connectivity.
Need to schedule this - missed it on 01/29. Paste in config snippet for review?
We'll be basing our conditional default routes on the presence of a core route from at least one of our three service providers.
The default-originate route-map must match on a route explicitly present in the routing table. Unfortunately, AS path and next-hop information are not valid parameters in this scenario.
We've chosen two core routes from each provider, routes which are integral to their backbones and extremely unlikely to disappear from BGP announcements:
As long as we are receiving one of these routes (from *any* source), we assume we still have a viable connection to the internet at large. The router will inject a default route into our internal OSPF areas as long as any of these provider routes are being learned via BGP.
ip access-list standard bgp-test-routes
permit 18.104.22.168 0.0.63.255
permit 22.214.171.124 0.0.63.255
permit 126.96.36.199 0.0.31.255
permit 188.8.131.52 0.0.31.255
permit 184.108.40.206 0.0.255.255
route-map bgp-active permit 10
match ip address bgp-test-routes
router ospf 1
default-information originate always route-map bgp-active
Changes applied to border1 and border2