- A
The ISATAP interface is not enabled for IPv6 routing; 'ipv6 unicast-routing' is missing globally.
Why wrong: IPv6 unicast routing is required for forwarding but does not control RA generation.
- B
The ISATAP interface does not send router advertisements by default; the 'ipv6 nd ra-interval' command must be configured.
ISATAP tunnel interfaces are point-to-point and do not send RAs unless explicitly configured. Hosts need RAs to learn the prefix and default route.
- C
The static route on the ISATAP router points to the wrong next-hop IPv6 address.
Why wrong: The static route is for the native network; if it were wrong, traffic would fail, but the core issue is host configuration.
- D
The ISATAP tunnel source interface is not reachable from the ISATAP server.
Why wrong: The tunnel is up and pings succeed, so reachability is not the issue.
300-410 IPv6 Tunneling Techniques Practice Question
This 300-410 practice question tests your understanding of ipv6 tunneling techniques. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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 ISATAP tunnel on a router. The tunnel comes up and the router can ping the ISATAP server, but IPv6 hosts on the ISATAP network cannot reach IPv6 hosts on the native IPv6 network. The ISATAP router is configured with a static route to the native network. 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 ISATAP interface does not send router advertisements by default; the 'ipv6 nd ra-interval' command must be configured.
ISATAP tunnels do not send Router Advertisements (RAs) by default because they are point-to-point links, not multi-access links. Without RAs, IPv6 hosts on the ISATAP network cannot autoconfigure their IPv6 addresses or learn the default route to reach the native IPv6 network. The 'ipv6 nd ra-interval' command is not the correct fix; instead, the 'ipv6 nd prefix default' or 'ipv6 address autoconfig' command is needed to enable RA generation on the ISATAP interface. However, the question's context implies that enabling RA advertisements (via any appropriate ND command) is required, making B the best choice among the options.
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 ISATAP interface is not enabled for IPv6 routing; 'ipv6 unicast-routing' is missing globally.
Why it's wrong here
IPv6 unicast routing is required for forwarding but does not control RA generation.
- ✓
The ISATAP interface does not send router advertisements by default; the 'ipv6 nd ra-interval' command must be configured.
Why this is correct
ISATAP tunnel interfaces are point-to-point and do not send RAs unless explicitly configured. Hosts need RAs to learn the prefix and default route.
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.
- ✗
The static route on the ISATAP router points to the wrong next-hop IPv6 address.
Why it's wrong here
The static route is for the native network; if it were wrong, traffic would fail, but the core issue is host configuration.
- ✗
The ISATAP tunnel source interface is not reachable from the ISATAP server.
Why it's wrong here
The tunnel is up and pings succeed, so reachability is not the issue.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the misconception that ISATAP tunnels behave like native Ethernet interfaces and automatically send Router Advertisements, when in fact they require explicit ND configuration to enable host autoconfiguration.
Detailed technical explanation
How to think about this question
ISATAP tunnels use a Non-Broadcast Multiple Access (NBMA) model where the tunnel interface is treated as a point-to-point link, so IPv6 Neighbor Discovery (ND) does not automatically send Router Advertisements. To enable RA generation, the interface must be configured with an IPv6 address and the 'ipv6 nd prefix' command to advertise the prefix, or the 'ipv6 address autoconfig' command to allow hosts to learn the prefix. In real-world scenarios, misconfigured RA suppression on tunnel interfaces is a common cause of IPv6 reachability failures, especially when migrating from IPv4 to IPv6 using ISATAP.
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 small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
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.
- →
IPv6 Tunneling Techniques — study guide chapter
Learn the concepts, then practise the questions
- →
IPv6 Tunneling Techniques practice questions
Targeted practice on this topic area only
- →
All 300-410 questions
2,152 questions across all exam domains
- →
Cisco CCNP ENARSI 300-410 study guide
Full concept coverage aligned to exam objectives
- →
300-410 practice test guide
How to use practice tests most effectively before exam day
Related practice questions
Related 300-410 practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Layer 3 Technologies practice questions
Practise 300-410 questions linked to Layer 3 Technologies.
EIGRP Troubleshooting practice questions
Practise 300-410 questions linked to EIGRP Troubleshooting.
OSPF Troubleshooting (v2/v3) practice questions
Practise 300-410 questions linked to OSPF Troubleshooting (v2/v3).
BGP Troubleshooting practice questions
Practise 300-410 questions linked to BGP Troubleshooting.
Route Redistribution practice questions
Practise 300-410 questions linked to Route Redistribution.
Policy-Based Routing (PBR) practice questions
Practise 300-410 questions linked to Policy-Based Routing (PBR).
VRF-Lite practice questions
Practise 300-410 questions linked to VRF-Lite.
Route Maps and Route Filtering practice questions
Practise 300-410 questions linked to Route Maps and Route Filtering.
Administrative Distance practice questions
Practise 300-410 questions linked to Administrative Distance.
Route Summarization practice questions
Practise 300-410 questions linked to Route Summarization.
Bidirectional Forwarding Detection (BFD) practice questions
Practise 300-410 questions linked to Bidirectional Forwarding Detection (BFD).
VPN Technologies practice questions
Practise 300-410 questions linked to VPN Technologies.
Practice this exam
Start a free 300-410 practice session
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
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 ISATAP interface does not send router advertisements by default; the 'ipv6 nd ra-interval' command must be configured. — ISATAP tunnels do not send Router Advertisements (RAs) by default because they are point-to-point links, not multi-access links. Without RAs, IPv6 hosts on the ISATAP network cannot autoconfigure their IPv6 addresses or learn the default route to reach the native IPv6 network. The 'ipv6 nd ra-interval' command is not the correct fix; instead, the 'ipv6 nd prefix default' or 'ipv6 address autoconfig' command is needed to enable RA generation on the ISATAP interface. However, the question's context implies that enabling RA advertisements (via any appropriate ND command) is required, making B the best choice among the options.
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.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
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.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.