OSPF ABR Type 3 LSA Filtering on Cisco IOS

[fugazz (Michal P)]

Hi Mercedes,
based on your first post…

@90forlifemcarreno

R4#sh ip route 3.3.3.3
Routing entry for 3.3.3.3/32
Known via “ospf 1”, distance 110, metric 2, type intra area
Last update from 192.168.34.3 on FastEthernet1/0, 01:53:04 ago
Routing Descriptor Blocks:

• 192.168.34.3, from 3.3.3.3, 01:53:04 ago, via FastEthernet1/0
  Route metric is 2, traffic share count is 1

R4 has routing entry for 3.3.3.3/32 in database, it is because R4 has interface in OSPF area 3.
R4 is an ABR router and ABRs always have OSPF database for all the areas they have interfaces in.
Because 4.4.4.4/32 is loopback on R4 then reachability is going to be there.

You can add another router, lets say R5 and interconnect it with R4. R4 and R5 interconnecting interfaces should belong to area 0. Because R4 is filtering 3.3.3.3/32 (based on seq 5 in OUT-AREA3) then R5 should not have reachability to 3.3.3.3/32.