Advertising default route via OSPF

OSPF can advertise a default router on a router into the rest of the OSPF domain. The command default-information originate in the router configuration mode will advertise the default route.

The command on its own will only advertise a default route if the local router has a default route of its own in the routing table. This can be overridden by adding the keyword always to advertise a default route regardless if one is present.