mediumMultiple Choice
300-410 Practice Question: Runs the following command on Router R1: R1# show…
A network engineer runs the following command on Router R1:
R1# show ipv6 eigrp neighbors
IPv6-EIGRP neighbors for process 100 H Address Interface Hold Uptime SRTT RTO Q Seq (sec) (ms) Cnt Num 0 FE80::A8BB:CCFF:FE00:2 Tunnel0 13 00:23:45 10 200 0 12 1 FE80::A8BB:CCFF:FE00:3 Tunnel1 12 00:22:10 15 200 0 15
Based on this output, which statement is correct?
⚠ Common exam trap
Cisco often tests the misconception that EIGRP for IPv6 uses global unicast addresses for neighbor adjacencies, but the output clearly shows link-local addresses, and candidates may incorrectly assume the tunnels must be GRE without evidence from the command output.
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
✓
EIGRP for IPv6 adjacencies are established over the tunnels.
The output shows two IPv6 EIGRP neighbors with link-local addresses (FE80::/10) on interfaces Tunnel0 and Tunnel1, and the adjacency is established and exchanging routes (Seq Num increasing). This confirms that EIGRP for IPv6 adjacencies are formed over these tunnel interfaces, making option C correct.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
EIGRP is not configured for IPv6.
Why it's wrong here
The output header 'IPv6-EIGRP neighbors for process 100' and the link-local FE80:: addresses confirm IPv6 EIGRP is running and has formed two adjacencies. The command itself only returns data when IPv6 EIGRP is configured. It would be the right conclusion if the command returned no neighbours or an error.
- ✗
The neighbors are using global unicast addresses.
Why it's wrong here
Both neighbour addresses begin with FE80::, the link-local prefix, so they are link-local addresses, not global unicast. EIGRPv6 forms adjacencies over link-local addresses by design. Global unicast addresses would appear only if the interfaces were configured with them and the command displayed those instead.
- ✓
EIGRP for IPv6 adjacencies are established over the tunnels.
Why this is correct
The neighbour table lists two adjacencies, each reachable via a tunnel interface (Tunnel0 and Tunnel1), with link-local next-hop addresses and non-zero uptime. This confirms EIGRP for IPv6 has formed neighbourships across the tunnel links, satisfying the scenario's requirement to verify adjacency establishment over those interfaces.
- ✗
The tunnels are using GRE encapsulation.
Why it's wrong here
The neighbour output shows link-local addresses on Tunnel interfaces and nothing about encapsulation, so GRE cannot be inferred; these could equally be IPsec or mGRE tunnels. GRE is chosen when you need to carry multicast or non-IP protocols across an IP-only transit network.
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.
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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.