Question 312 of 2,152
DMVPNhardMultiple ChoiceObjective-mapped

EIGRP Stub Configuration in DMVPN

This 300-410 practice question tests your understanding of dmvpn. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. A key principle to apply: dMVPN Phase 2. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.

In a DMVPN Phase 2 network with EIGRP, R1 (hub) and R2 (spoke) are configured with EIGRP stub leaking. R2 is a stub router with 'eigrp stub connected summary'. R3 (another spoke) is not a stub. R2's loopback 10.0.0.1/32 is not reachable from R3, even though R2 advertises it via EIGRP. What is the root cause?

Quick Answer

The answer is that R2’s loopback is unreachable from R3 because R2 is configured with 'eigrp stub receive-only', which completely suppresses all outbound route advertisements, including connected routes like the loopback. In a DMVPN Phase 2 network, the 'eigrp stub connected summary' command normally allows a spoke to advertise only its directly connected and summary routes while blocking routes learned from other peers. However, if 'receive-only' is also applied, it overrides those keywords and prevents any route from being sent, making the loopback invisible to other spokes. This scenario tests your understanding of EIGRP stub behavior in DMVPN, a common trap on the Cisco CCNP ENARSI 300-410 exam where candidates mistakenly assume 'connected summary' guarantees advertisement. Remember: 'receive-only' is the silent killer—it stops all outbound EIGRP updates, no matter what other stub keywords are present.

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

NHRP is not configured on R2, preventing route advertisement.

In DMVPN Phase 2, EIGRP stub leaking allows the hub to advertise spoke routes to other spokes, but the next-hop remains the spoke's tunnel IP. For R3 to install the route to 10.0.0.1/32, it must have an NHRP mapping to reach R2's tunnel IP. Without NHRP configured on R2, R3 cannot resolve the next-hop, making the route unreachable. The EIGRP stub configuration is correct, but NHRP is missing.

Key principle: DMVPN Phase 2

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

  • R2 is configured with 'eigrp stub receive-only', which prevents it from advertising any routes, including connected ones.

    Why it's wrong here

    Incorrect. The stem explicitly states that R2 is configured with 'eigrp stub connected summary', not 'receive-only'. 'Receive-only' would contradict the given configuration.

  • R3 has a distribute-list filtering the prefix 10.0.0.1/32 from EIGRP updates.

    Why it's wrong here

    Incorrect. There is no evidence of a distribute-list on R3; the question does not mention any filtering. The issue is likely network-layer reachability, not filtering.

  • R2's loopback is not in the same EIGRP autonomous system as the tunnel.

    Why it's wrong here

    Incorrect. The stem states that R2 advertises the loopback via EIGRP, meaning it is in the same autonomous system. If it were not, the route would not be advertised at all.

  • NHRP is not configured on R2, preventing route advertisement.

    Why this is correct

    Correct. Without NHRP on R2, R3 cannot resolve R2's tunnel IP to a physical address, so the route to 10.0.0.1/32 remains unreachable despite being advertised.

    Related concept

    DMVPN Phase 2

Common exam traps

Common exam trap: answer the scenario, not the keyword

Candidates often overlook the necessity of NHRP in DMVPN Phase 2 when focusing on EIGRP stub configuration. Even with proper stub leaking, a spoke without NHRP will prevent other spokes from routing to its networks.

Detailed technical explanation

How to think about this question

Treat this as a scenario question. Identify the problem, the constraint, and the best action. Then compare each option against those facts.

KKey Concepts to Remember

  • DMVPN Phase 2
  • NHRP
  • EIGRP Stub Leaking
  • Route Reachability

TExam Day Tips

  • Watch for words such as best, first, most likely and least administrative effort.
  • Review why wrong options are wrong, not only why the correct option is correct.

Key takeaway

DMVPN Phase 2

Real-world example

How this comes up in practice

A practitioner preparing for the 300-410 exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. DMVPN Phase 2 Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.

Visual reference

Client Recursive Resolver Root DNS (13 root servers) TLD DNS (.com, .org, …) Authoritative example.com query IP addr answer

Quick reference

Routing Protocol Comparison

ProtocolMetricMax HopsAlgorithmType
RIP v2Hop count15Bellman-FordDistance vector
OSPFCost (bandwidth)UnlimitedDijkstra (SPF)Link state
EIGRPComposite metricUnlimitedDUALHybrid
IS-ISCostUnlimitedDijkstraLink state
BGPPolicy / attributesUnlimitedPath vectorPath vector

RIP's 15-hop limit makes it unsuitable for large networks. OSPF and EIGRP dominate modern enterprise deployments.

What to study next

Got this wrong? Here's your next step.

Review dMVPN Phase 2, then practise related 300-410 questions on the same topic to reinforce the concept.

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FAQ

Questions learners often ask

What does this 300-410 question test?

DMVPN — This question tests DMVPN — DMVPN Phase 2.

What is the correct answer to this question?

The correct answer is: NHRP is not configured on R2, preventing route advertisement. — In DMVPN Phase 2, EIGRP stub leaking allows the hub to advertise spoke routes to other spokes, but the next-hop remains the spoke's tunnel IP. For R3 to install the route to 10.0.0.1/32, it must have an NHRP mapping to reach R2's tunnel IP. Without NHRP configured on R2, R3 cannot resolve the next-hop, making the route unreachable. The EIGRP stub configuration is correct, but NHRP is missing.

What should I do if I get this 300-410 question wrong?

Review dMVPN Phase 2, then practise related 300-410 questions on the same topic to reinforce the concept.

What is the key concept behind this question?

DMVPN Phase 2

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Last reviewed: Jun 18, 2026

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