mediumMultiple ChoiceObjective-mapped
300-410 Practice Question: Is troubleshooting a DMVPN phase 2 network where…
A network engineer is troubleshooting a DMVPN phase 2 network where the hub router is not forming an NHRP adjacency with a spoke. The spoke router is configured with 'ip nhrp nhs 10.0.0.1' and 'ip nhrp map 10.0.0.1 192.168.1.1'. The hub's tunnel interface IP is 10.0.0.1, and the physical interface IP is 192.168.1.1. The engineer pings the hub's tunnel IP from the spoke and it succeeds. However, 'show ip nhrp' on the spoke shows no NHRP entries. What is the most likely cause?
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The hub router has 'ip nhrp authentication DMVPN' configured, but the spoke does not.
NHRP registration requires the spoke to send a Registration Request to the hub. If the hub does not respond, the spoke will not have NHRP entries. A common cause is that the hub's NHRP authentication is configured with a password, but the spoke's NHRP authentication is missing or mismatched.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
The hub router has 'ip nhrp authentication DMVPN' configured, but the spoke does not.
Why this is correct
Correct because NHRP authentication must match between hub and spoke for registration to succeed.
- ✗
The spoke's tunnel interface is in a different VRF than the hub's.
Why it's wrong here
Incorrect because VRF mismatch would prevent ping, but ping succeeds.
- ✗
The hub's tunnel interface has 'no ip nhrp server-only' configured.
Why it's wrong here
Incorrect because 'ip nhrp server-only' is not a standard command; the hub is the NHS by default.
- ✗
The spoke's NHRP map is incorrect; it should map the hub's tunnel IP to the hub's tunnel IP.
Why it's wrong here
Incorrect because the NHRP map maps the tunnel IP to the physical IP, which is correct.
Go deeper
Related to this question
Learn chapter
Introduction to ENARSI Exam and Network Fundamentals
Key term
DMVPN Phase 2
DMVPN Phase 2 is an advanced Cisco routing technology that allows spoke routers to communicate directly with one another without sending traffic through a central hub, using dynamic routing protocols and multipoint GRE tunnels.
About these practice questions
This 300-410 question is part of Courseiva's 1,966-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam dumps. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 300-410 practice question is part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 300-410 exam.