300-410 VPN Technologies Practice Question
A network administrator is troubleshooting a DMVPN Phase 3 hub-and-spoke deployment where the hub uses mGRE and spokes use mGRE. Spoke-to-spoke traffic works, but the administrator notices that the spokes are installing host routes for other spokes in their routing tables. Which DMVPN Phase 3 feature is responsible for adding these specific host routes?
⚠ Common exam trap
It's easy for candidates to confuse the hub-side redirect trigger with the spoke-side shortcut that actually installs the host route in the routing table.
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 shortcut on the spokes
In DMVPN Phase 3, the hub uses NHRP redirect to inform a spoke that a better path exists, and the spokes use NHRP shortcut to resolve the destination and install a host route for the peer tunnel address. Those host routes are what let the spoke forward traffic directly to another spoke. Without NHRP shortcut on the spokes, the redirect messages would not result in usable direct paths.
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 registration no-unique on the spokes
Why it's wrong here
The ip nhrp registration no-unique command allows multiple spokes to register with the same tunnel address, which is useful behind NAT or for redundancy. It does not create host routes for peer tunnel addresses on the spokes; that behavior comes from the shortcut mechanism after NHRP resolution succeeds.
- ✗
ip nhrp map multicast dynamic on the hub
Why it's wrong here
The ip nhrp map multicast dynamic command lets the hub dynamically create multicast NHRP mappings for registering spokes. It affects how multicast traffic is replicated to spokes and does not cause spokes to install host routes for peer tunnel addresses, so it is unrelated to the observed host routes.
- ✓
NHRP shortcut on the spokes
Why this is correct
With NHRP shortcut, the spoke installs a host route for the destination spoke tunnel address after successful NHRP resolution. This route points at the tunnel interface and allows the spoke to send traffic directly to the peer, bypassing the hub. The host routes observed in the routing table are the visible result of NHRP shortcut operation.
- ✗
NHRP redirect on the hub
Why it's wrong here
NHRP redirect is the hub-side mechanism that tells a spoke that a more optimal path exists for a flow it sent through the hub. It triggers the spoke to initiate NHRP resolution, but redirect itself does not install host routes in the routing table; it is the shortcut mechanism that consumes the resolution result.
Visual reference
Go deeper
Related to this question
Learn chapter
OSPF Route Summarization and Filtering
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.
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.
About these practice questions
This 300-410 question is part of Courseiva's 1,401-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam dumps. Learn why practice questions differ from exam dumps →
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.