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300-410 Practice Question: Which THREE symptoms indicate a potential issue…

Which THREE symptoms indicate a potential issue with NHRP registration in a DMVPN network? (Choose THREE.)

⚠ Common exam trap

300-410 often tests the confusion between tunnel interface status and NHRP registration status; candidates might think a tunnel being 'UP/UP' guarantees NHRP registration, but NHRP can still fail due to authentication or network ID mismatches.

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 spoke router does not receive an NHRP Registration Reply from the hub.

Option A is correct because a spoke initiates NHRP registration by sending an NHRP Registration Request to the hub's NBMA address, and the hub must respond with an NHRP Registration Reply; failure to receive that reply directly indicates the registration exchange is failing. Option B is correct because a successful registration causes the hub to install an NHRP cache entry mapping the spoke's tunnel IP to its NBMA address, so a missing entry confirms the spoke never successfully registered. Option C is correct because the tunnel interface can be UP/UP (mGRE is stateless and comes up regardless of NHRP), yet the NHRP registration status explicitly showing 'NOT REGISTERED' is a direct symptom of an NHRP registration problem. Option D is not correct because an UP/DOWN tunnel interface points to a Layer 1/2 or tunnel source/destination reachability problem rather than an NHRP registration failure. Option E is not correct because routes learned from the hub indicate that routing adjacencies and reachability are working, which is not a symptom of failed NHRP registration.

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 spoke router does not receive an NHRP Registration Reply from the hub.

    Why this is correct

    A missing NHRP Registration Reply directly evidences failed registration: the spoke sent a Registration Request but the hub never acknowledged it, so no mapping is installed. This satisfies the stem's requirement for a registration-specific symptom, distinguishing it from tunnel or routing faults that occur after successful registration.

  • ✓

    The hub router's NHRP cache does not contain an entry for the spoke.

    Why this is correct

    A missing hub NHRP cache entry for a spoke directly evidences failed registration, since the hub only populates its cache after receiving a valid NHRP Registration Request from that spoke's tunnel address. This satisfies the stem's requirement for a registration symptom, distinguishing it from data-plane or routing failures that leave registration intact.

  • ✓

    The spoke router's tunnel interface shows 'UP/UP' but NHRP registration status is 'NOT REGISTERED'.

    Why this is correct

    A tunnel interface can report UP/UP while NHRP registration has failed, because line protocol reflects only the underlying transport, not NBMA mapping success. The 'NOT REGISTERED' status directly evidences that the spoke's registration request to the hub was rejected or unanswered, satisfying the stem's requirement for an NHRP registration symptom.

  • ✗

    The spoke router's tunnel interface shows 'UP/DOWN'.

    Why it's wrong here

    An UP/DOWN tunnel state indicates a line-protocol or underlying transport failure, not an NHRP registration fault; NHRP issues typically leave the tunnel up while resolution fails. It is tempting because tunnel state is the first thing engineers check, and UP/DOWN would be the correct symptom when the physical or NBMA path itself is broken.

  • ✗

    The spoke router's routing table shows routes learned from the hub.

    Why it's wrong here

    Routes learned from the hub are the expected, healthy outcome of successful NHRP registration and dynamic routing, so their presence is not a symptom of failure. It is tempting because a missing route is a genuine indicator, and checking the routing table would be the correct step when verifying that spoke-to-spoke or hub reachability has actually propagated.

About these practice questions

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JA

Written and reviewed by Johnson Ajibi, MSc IT Security

Senior Network & Security Engineer · founder of Courseiva

Last reviewed September 2026 · checked against the official Cisco exam blueprint

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.