300-410 Layer 3 Technologies Practice Question
A network engineer is troubleshooting a DMVPN Phase 3 hub-and-spoke topology. Spoke routers are Cisco IOS devices running EIGRP as the routing protocol. The engineer wants to ensure that spoke-to-spoke traffic does not go through the hub after the initial path setup, and that spoke routers can dynamically form direct tunnels. Which NHRP command must be configured on the hub to enable this behavior?
⚠ Common exam trap
Many exam-takers confuse the roles of 'ip nhrp redirect' and 'ip nhrp shortcut', mistakenly placing the shortcut command on the hub instead of the spoke.
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
✓
ip nhrp redirect
For DMVPN Phase 3, the hub must be configured with 'ip nhrp redirect' to send redirect messages to spokes, allowing them to establish direct tunnels. Spokes must have 'ip nhrp shortcut' to act on those redirects. Without the hub redirect, spokes would continue sending traffic through the hub even after initial NHRP resolution.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
ip nhrp map multicast dynamic
Why it's wrong here
The 'ip nhrp map multicast dynamic' command enables the hub to replicate multicast packets to dynamically registered spokes, which is useful for routing protocols like EIGRP. However, it does not enable spoke-to-spoke direct tunnel formation or bypass the hub for data traffic; that requires NHRP redirect and shortcut.
- ✓
ip nhrp redirect
Why this is correct
The 'ip nhrp redirect' command on the hub enables NHRP redirect messages, which inform spokes of a better direct path to another spoke. This allows spoke-to-spoke communication without traversing the hub after initial resolution. It is essential for DMVPN Phase 3 and works with 'ip nhrp shortcut' on spokes.
- ✗
ip nhrp network-id 1
Why it's wrong here
The 'ip nhrp network-id' command assigns an NHRP network identifier and must match on all DMVPN routers for NHRP to function. While necessary for basic DMVPN operation, it does not enable spoke-to-spoke direct communication or bypass the hub; it is simply an identifier for the NHRP domain.
- ✗
ip nhrp shortcut
Why it's wrong here
The 'ip nhrp shortcut' command is configured on spoke routers, not the hub. It allows the spoke to use NHRP resolution to bypass the hub when sending traffic to another spoke. On the hub, this command has no effect for enabling spoke-to-spoke direct tunnels; the hub requires 'ip nhrp redirect' instead.
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
EIGRP Neighbor Adjacency and Basics
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
DMVPN Phase 3
DMVPN Phase 3 is a Cisco networking technology that allows branch offices to connect directly to each other without always going through a central hub, but with smarter routing that lets the hub control the traffic paths more efficiently.
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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.