OSPF NSSA ABR advertises default route
In an NSSA OSPF topology, the following command will generate a Type 7 default route:
router ospf 1 area 1 nssa default-information-originate
The following rules apply:
- When applied to an NSSA ASBR, this will only generate a default route if:
- there is a valid default route in the routing table that has been learned through a non-OSPF protocol.
- the keyword
always
is added at the end of the command.
- When applied to an NSSA ABR, this will generate a default route with or without a valid default route in the routing table.
Links:
https://www.cisco.com/c/en/us/support/docs/ip/open-shortest-path-first-ospf/6208-nssa.html#type7
https://networklessons.com/ospf/how-to-configure-ospf-nssa-not-so-stubby-area/
https://forum.networklessons.com/t/how-to-configure-ospf-nssa-not-so-stubby-area/938/41?u=lagapides