14.3.3 Checking routes resulting from SPF calculations on OSPF [SL-L3A]

If a filter invalidates an external AS route or NSSA route computed by the SPF algorithm of the OSPF protocol, the route is still entered into the routing table but as an invalid route. You can check the external AS routes and NSSA routes that the OSPF protocol has generated, including invalid routes, by executing the show ip route operation command with the all-routes and -T ospf external parameters specified.

Figure 14-4: Displaying external OSPF AS and NSSA routes
> show ip route all-routes -T ospf external Date 20XX/07/14 12:00:00 UTC Status Codes: * valid, > active, r RIB failure Total: 2 routes Destination Next Hop Interface Metric Protocol Age > 200.1/24 192.168.1.145 VLAN0007 1/1 OSPF ext2 52s, Tag: 10 200.200.1/24 192.168.1.145 VLAN0007 1/1 OSPF ext2 52s, Tag: 0

Figure 14-4: Displaying external OSPF AS and NSSA routes

> show ip route all-routes -T ospf external
Date 20XX/07/14 12:00:00 UTC
Status Codes: * valid, > active, r RIB failure
Total: 2 routes
   Destination       Next Hop        Interface   Metric  Protocol  Age
*> 200.1/24          192.168.1.145   VLAN0007    1/1     OSPF ext2 52s, Tag: 10
*  200.200.1/24      192.168.1.145   VLAN0007    1/1     OSPF ext2 52s, Tag:  0