hardMultiple ChoiceObjective-mapped
300-410 Practice Question: In a DMVPN network with VRF-Lite, Router R1 (hub)…
In a DMVPN network with VRF-Lite, Router R1 (hub) and R2 (spoke) are configured for VRF-A. The DMVPN tunnel is up, but spoke-to-spoke traffic between R2 and R3 (another spoke) fails. R1 has configuration: interface Tunnel0, ip vrf forwarding VRF-A, ip address 172.16.0.1 255.255.255.0, tunnel source Gig0/0, tunnel mode gre multipoint. R2 has similar configuration with tunnel destination dynamic. The NHRP map for R3 is missing on R2. What is the root 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 NHRP mapping for R3 is missing on R2, preventing direct spoke-to-spoke tunnel establishment.
In DMVPN, spoke-to-spoke tunnels require NHRP resolution. If R2 does not have an NHRP map for R3, it cannot establish a direct tunnel. The hub (R1) should facilitate NHRP resolution, but if the VRF configuration is not properly propagated, NHRP may fail. The root cause is that the NHRP mapping is missing, often due to VRF mismatch in NHRP configuration or because the hub is not properly forwarding NHRP requests.
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 NHRP mapping for R3 is missing on R2, preventing direct spoke-to-spoke tunnel establishment.
Why this is correct
Correct: Without NHRP mapping, R2 cannot send traffic directly to R3; it must go through the hub.
- ✗
The tunnel mode should be gre multipoint on all spokes.
Why it's wrong here
Incorrect: Spokes typically use tunnel mode gre multipoint or point-to-point; the issue is NHRP.
- ✗
The VRF must be removed from the tunnel interface for DMVPN to work.
Why it's wrong here
Incorrect: VRF can be used with DMVPN; the issue is NHRP.
- ✗
The hub router must have a static route for each spoke.
Why it's wrong here
Incorrect: DMVPN uses dynamic routing; static routes are not required.
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.
Key term
MPLS Layer 3 VPN
A technology that uses Multiprotocol Label Switching to create secure, scalable virtual private networks that connect multiple sites at the network layer, where the service provider manages routing between customer sites.
About these practice questions
Courseiva writes every 300-410 question from scratch — 1,966 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or 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.