OSPF default routes

1. To have an OSPF default route when redistributing, you will need an ip route or ip default-network.
2. OSPF creates an LSA type 5.
3. Does not generate default routes in stubby, totally stubby areas [no 5 allowed].
4. If you need a default route make the OSPF area an nssa area, then type 7 default.
5. The "area x nssa default-information-originate" will always generate a default route into the nssa area, whether there is a default or not.
6. The area x nssa defa-info orig generates default route based on following condition:
   • If it is an NSSA ASBR: it will generate the default only if it has one itself.
   • If it is an NSSA ABR: it will generate default route irrespective of it having it.