350-401 Question 531
Single answerAn enterprise network is using EIGRP for its internal routing. The network administrator wants to configure dynamic EIGRP neighbors on a shared Ethernet segment to simplify neighbor discovery while ensuring the feature works as intended. Which configuration step is required to enable dynamic EIGRP neighbor discovery?
- A
Enable EIGRP on the Ethernet interface without specifying a neighbor command.
- B
Manually configure EIGRP neighbors using the 'neighbor' command on the interface.
- C
Enable the 'passive-interface' command on the Ethernet interface.
- D
Disable multicast on the Ethernet interface and use unicast for neighbor communication.
Show answer and explanation
Correct answer: A
Explanation
Dynamic neighbor discovery in EIGRP occurs automatically on broadcast and multi-access networks, such as Ethernet, when EIGRP is enabled on the interface. There is no need to manually configure neighbors or modify multicast settings. This simplifies neighbor establishment and reduces administrative overhead.
- A. Correct.
This is the correct answer because EIGRP supports dynamic neighbor discovery by default on broadcast and multi-access networks, such as Ethernet. Simply enabling EIGRP on the interface without specifying the 'neighbor' command allows dynamic neighbor relationships to form.
- B. Incorrect.
This is incorrect because manually configuring neighbors with the 'neighbor' command disables dynamic neighbor discovery and forces the router to use unicast communication for EIGRP updates.
- C. Incorrect.
This is incorrect because enabling the 'passive-interface' command prevents EIGRP from sending or receiving hello packets on the interface, which effectively disables dynamic neighbor discovery.
- D. Incorrect.
This is incorrect because disabling multicast on the interface and using unicast communication requires manually configured neighbors, which contradicts the goal of dynamic neighbor discovery.