FCSS – Network Security Specialist 7.4 — Question 60

What are two reasons that an OSPF router does not have any type 5 link-state advertisements (LSAs) in its link-state database (LSDB)? (Choose two.)

Answer options

• A. The local router is located in a stub area.
• B. IP protocol 89 is blocked between the local router and its peer.
• C. There is no autonomous system border router (ASBR) in the network.
• D. The peer of the local router is using a prefix-list-out configuration to prevent all type 5 LSAs to be advertised.

Correct answer: A, C

Explanation

The correct answers are A and C because a router in a stub area is designed to not receive type 5 LSAs, and having no ASBR means that type 5 LSAs are not generated at all. Options B and D are incorrect because they pertain to connectivity issues or configurations that do not inherently prevent the presence of type 5 LSAs in the LSDB.