mediumMultiple Choice
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 learning the loopback interface routes from the spokes via EIGRP. The spokes have EIGRP configured on the tunnel interface and are advertising their loopback0 interface. The hub's EIGRP neighbor relationship with the spokes is established. However, the hub's routing table does not contain the loopback routes. The engineer checks the spoke's EIGRP configuration and sees that the loopback interface is not included in any network statement. What is the most likely cause?
⚠ Common exam trap
300-410 often tests the assumption that EIGRP automatically advertises all connected interfaces, when in fact it only advertises those matched by network statements, leading candidates to overlook missing network commands.
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's EIGRP network statement does not include the loopback subnet.
The hub is not learning the loopback routes because the spoke's EIGRP configuration does not include the loopback subnet in any network statement. EIGRP only advertises interfaces that are explicitly matched by a network command. Since the loopback is not included, it is not advertised to the hub.
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's EIGRP network statement does not include the loopback subnet.
Why this is correct
EIGRP advertises only interfaces matched by a network statement. The loopback0 subnet is absent from any network statement on the spoke, so it is never placed into EIGRP and cannot be advertised to the hub, despite the neighbour adjacency being up.
- ✗
The hub's EIGRP is configured with a distribute-list that filters the loopback routes.
Why it's wrong here
A hub distribute-list would filter routes the hub receives, but the spoke never advertises loopback0 since no network statement includes it, so nothing reaches the hub to filter. Distribute-lists are tempting for controlling EIGRP advertisements, yet they cannot explain a route absent at the source.
- ✗
The tunnel interface on the spoke has 'no ip split-horizon' configured.
Why it's wrong here
Split-horizon suppression applies to routes learned out the same interface, but the loopback is never advertised because no network statement covers it, so the hub receives nothing regardless. Disabling split-horizon is tempting in NBMA designs, yet it cannot inject a route the spoke never originates.
- ✗
The loopback interface on the spoke is in a different VRF than the tunnel interface.
Why it's wrong here
VRF separation would break the EIGRP neighbour relationship or place the route in another table, yet the stem confirms neighbours are established and the loopback simply is not matched by any network statement. VRF mismatch is tempting in segmented designs, but it does not fit the stated configuration.
Visual reference
Quick reference
Routing Protocol Comparison
| Protocol | Metric | Max Hops | Algorithm | Type |
|---|---|---|---|---|
| RIP v2 | Hop count | 15 | Bellman-Ford | Distance vector |
| OSPF | Cost (bandwidth) | Unlimited | Dijkstra (SPF) | Link state |
| EIGRP | Composite metric | Unlimited | DUAL | Hybrid |
| IS-IS | Cost | Unlimited | Dijkstra | Link state |
| BGP | Policy / attributes | Unlimited | Path vector | Path vector |
RIP's 15-hop limit makes it unsuitable for large networks. OSPF and EIGRP dominate modern enterprise deployments.
Go deeper
Related to this question
Learn chapter
ACL-Based Traffic Filtering and Policy-Based Routing
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.
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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.