300-440 Question 203
Select 2An organization has deployed an OSPF-based routing environment. To improve infrastructure security, the network administrator decides to authenticate OSPF neighbor relationships. Which of the following configurations will ensure OSPF authentication is properly implemented?
- A
Configure MD5 authentication on the OSPF interfaces with the same key on both ends.
- B
Enable OSPFv3 encryption-only mode to secure all communication.
- C
Use plaintext passwords for OSPF authentication.
- D
Apply an authentication configuration under the OSPF process and ensure interfaces use the same key.
- E
Use SHA-based authentication to replace MD5 in OSPFv2.
Show answer and explanation
Correct answers: A, D
Explanation
OSPF authentication is essential for securing routing exchanges and preventing unauthorized devices from forming OSPF adjacencies. MD5 authentication (for OSPFv2) or IPsec (for OSPFv3) are commonly used methods. Correctly configuring the authentication at the interface or process level with matching keys ensures secure OSPF neighbor relationships while avoiding potential misconfigurations or vulnerabilities.
- A. Correct.
Correct: Configuring MD5 authentication ensures OSPF messages are authenticated using a shared key, preventing unauthorized routers from forming adjacencies. The key must match on both ends.
- B. Incorrect.
Incorrect: OSPFv3 supports IPsec for authentication and encryption, but 'encryption-only' does not secure authentication. Authentication must be explicitly configured.
- C. Incorrect.
Incorrect: Using plaintext passwords is insecure and not recommended. OSPF supports MD5 or IPsec for secure authentication.
- D. Correct.
Correct: Applying authentication at the OSPF process level ensures all related OSPF interfaces must use the same authentication method and key.
- E. Incorrect.
Incorrect: OSPFv2 does not support SHA-based authentication. MD5 remains the standard for OSPFv2 in most implementations.