- A
The tunnel interface does not have an IPv6 address configured; manual tunnels require an IPv6 address on the tunnel interface for the connected route to exist.
Without an IPv6 address on the tunnel interface, there is no connected route to redistribute. The tunnel may still pass traffic using the tunnel source/destination, but no IPv6 subnet is directly connected.
- B
OSPFv3 does not support redistribution of connected routes from tunnel interfaces.
Why wrong: OSPFv3 supports redistribution from any interface, including tunnels.
- C
The 'redistribute connected' command must include the 'metric-type' keyword to be effective.
Why wrong: The metric-type is optional; redistribution still occurs without it.
- D
The tunnel interface is in a different OSPFv3 process than the one where redistribution is configured.
Why wrong: If the tunnel interface is in the same OSPFv3 process, redistribution should work.
Quick Answer
The answer is that the tunnel interface lacks an IPv6 address, which prevents the connected route from existing for redistribution. In a manual IPv6 tunnel, the tunnel interface itself must be assigned an IPv6 address; without it, there is no connected IPv6 route associated with that interface. The `redistribute connected` command under OSPFv3 can only advertise routes that are directly connected to an interface, so if the tunnel interface has no IPv6 address, no such route exists to redistribute—even though the tunnel is up and the endpoints can ping each other’s tunnel addresses. On the Cisco CCNP ENARSI 300-410 exam, this scenario tests your understanding that a tunnel’s operational status is separate from its addressing; a common trap is assuming a working tunnel implies a connected route. Remember: for redistribution, a tunnel interface must have its own IPv6 address—think “no address, no route to redistribute.”
300-410 IPv6 Tunneling Techniques Practice Question
This 300-410 practice question tests your understanding of ipv6 tunneling techniques. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. 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.
An engineer configures an IPv6 manual tunnel between two routers. The tunnel is up and both routers can ping each other's tunnel IPv6 addresses. However, when the engineer tries to redistribute a connected IPv6 route from the tunnel into OSPFv3, the route is not advertised. The OSPFv3 process includes the tunnel interface. What is the most likely cause?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"most likely"Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
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 tunnel interface does not have an IPv6 address configured; manual tunnels require an IPv6 address on the tunnel interface for the connected route to exist.
For a manual IPv6 tunnel, the tunnel interface must have an IPv6 address configured. Without an IPv6 address on the tunnel interface, there is no connected IPv6 route for that interface, so the 'redistribute connected' command under OSPFv3 has no route to advertise. The tunnel being up and pingable between tunnel IPv6 addresses indicates the tunnel itself is operational, but the absence of an IPv6 address on the tunnel interface means no connected route exists to redistribute.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
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 tunnel interface does not have an IPv6 address configured; manual tunnels require an IPv6 address on the tunnel interface for the connected route to exist.
Why this is correct
Without an IPv6 address on the tunnel interface, there is no connected route to redistribute. The tunnel may still pass traffic using the tunnel source/destination, but no IPv6 subnet is directly connected.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
OSPFv3 does not support redistribution of connected routes from tunnel interfaces.
Why it's wrong here
OSPFv3 supports redistribution from any interface, including tunnels.
- ✗
The 'redistribute connected' command must include the 'metric-type' keyword to be effective.
Why it's wrong here
The metric-type is optional; redistribution still occurs without it.
- ✗
The tunnel interface is in a different OSPFv3 process than the one where redistribution is configured.
Why it's wrong here
If the tunnel interface is in the same OSPFv3 process, redistribution should work.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the misconception that a tunnel being up and pingable implies a connected IPv6 route exists, but in manual tunnels, the tunnel interface must have its own IPv6 address for a connected route to be present and redistributable.
Detailed technical explanation
How to think about this question
A manual IPv6 tunnel (RFC 4213) requires an IPv6 address on the tunnel interface to generate a connected route; without it, the interface is considered unnumbered for IPv6, and no connected prefix exists. Under the hood, OSPFv3's 'redistribute connected' command only injects routes from the IPv6 unicast routing table that are marked as connected (C), which are absent if the tunnel interface lacks an IPv6 address. In real-world scenarios, this often occurs when engineers focus on tunnel source/destination and IPv4 reachability but forget to assign an IPv6 address to the tunnel interface itself.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
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
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A network engineer at a university connects two campus buildings via a fibre link. Both routers run OSPF, but no adjacency forms — even though both routers can ping each other. The engineer finds one router is in area 0 and the other in area 1. OSPF adjacency requires matching area numbers, hello/dead timers, and network type. IP reachability alone is not enough.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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IPv6 Tunneling Techniques — study guide chapter
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FAQ
Questions learners often ask
What does this 300-410 question test?
IPv6 Tunneling Techniques — This question tests IPv6 Tunneling Techniques — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The tunnel interface does not have an IPv6 address configured; manual tunnels require an IPv6 address on the tunnel interface for the connected route to exist. — For a manual IPv6 tunnel, the tunnel interface must have an IPv6 address configured. Without an IPv6 address on the tunnel interface, there is no connected IPv6 route for that interface, so the 'redistribute connected' command under OSPFv3 has no route to advertise. The tunnel being up and pingable between tunnel IPv6 addresses indicates the tunnel itself is operational, but the absence of an IPv6 address on the tunnel interface means no connected route exists to redistribute.
What should I do if I get this 300-410 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 24, 2026
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.
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