350-401 Question 604
Select 3A network administrator is troubleshooting SNMP communication issues between a network management system (NMS) and a router. The NMS is configured to use SNMPv3 for secure communication. However, SNMP queries are failing, and no responses are returned from the router. Upon verifying the configuration, the administrator confirms that the SNMPv3 user and group are correctly configured on the router. Which of the following could be the cause of the issue?
- A
The SNMPv3 authentication protocol is mismatched between the NMS and the router.
- B
The SNMPv3 privacy (encryption) protocol is disabled on the router.
- C
The SNMPv3 user is not assigned the appropriate access control permissions on the router.
- D
The router's SNMP agent is configured with an access list that blocks requests from the NMS.
- E
The SNMP community string is mismatched between the NMS and the router.
Show answer and explanation
Correct answers: A, C, D
Explanation
SNMPv3 uses secure methods for authentication and optional encryption. Communication issues can arise if the authentication protocols are mismatched, the SNMPv3 user lacks appropriate access permissions, or if an access list blocks requests. SNMPv3 does not use community strings, so mismatched community strings only apply to SNMPv1/v2c and are irrelevant here.
- A. Correct.
Correct. SNMPv3 requires both the NMS and the router to use the same authentication protocol (e.g., MD5 or SHA). A mismatch will prevent successful communication.
- B. Incorrect.
Incorrect. While SNMPv3 supports optional encryption, disabling the privacy protocol does not prevent SNMP queries from functioning unless encryption is specifically required by the NMS.
- C. Correct.
Correct. In SNMPv3, the user must be assigned the correct access privileges (e.g., read-only or read-write) to successfully respond to queries.
- D. Correct.
Correct. An access list on the router could restrict SNMP traffic from the NMS if the NMS IP is not explicitly permitted.
- E. Incorrect.
Incorrect. SNMP community strings are used in SNMPv1/v2c, not SNMPv3, so this is not relevant for the given scenario.