- A
The distribute-list is applied to the wrong direction; it should be outbound to filter routes being advertised.
Why wrong: Inbound distribute-lists filter routes received, which should prevent installation. The issue is that the route may be learned from another source.
- B
The route is also learned via another OSPF neighbor that is not filtered by the distribute-list.
A distribute-list only affects routes received on the specific interface. If the same route is learned from another neighbor, it will still be installed.
- C
The distribute-list uses an ACL that does not match the route exactly, so the route is permitted.
Why wrong: If the ACL does not match, the route would be permitted by default (implicit permit), but the problem states the engineer intended to filter it.
- D
The distribute-list is applied after the route is already installed in the routing table, so it has no effect.
Why wrong: Distribute-lists affect the installation process; they are applied before the route is added to the routing table.
Quick Answer
The answer is that the route is also learned via another OSPF neighbor not filtered by the distribute-list. This occurs because an OSPF distribute-list applied inbound on a specific interface only filters routes received from that particular neighbor; it does not prevent the router from installing the same route if it is also learned from a different OSPF neighbor or process. On the Cisco CCNP ENARSI 300-410 exam, this scenario tests your understanding that OSPF route filtering is neighbor-specific, not global—a common trap is assuming a distribute-list blocks the route entirely, when in fact OSPF will still select the best metric route from any unfiltered source. For OSPF distribute-list filtering with multiple sources, remember that each neighbor is an independent path; filtering one does not block the others. Memory tip: “Filter the neighbor, not the network”—the distribute-list silences the speaker, not the song.
300-410 Device Access Control Practice Question
This 300-410 practice question tests your understanding of device access control. 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 a route-map to filter OSPF routes using a distribute-list. The distribute-list is applied inbound on an OSPF interface. Unexpectedly, the router still installs the filtered routes. Which is the most likely explanation?
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 route is also learned via another OSPF neighbor that is not filtered by the distribute-list.
When a distribute-list is applied inbound on an OSPF interface, it filters routes received from that specific neighbor only. If the same route is also learned from another OSPF neighbor (or via a different OSPF process) that is not covered by the distribute-list, the router will still install that route from the unfiltered source. This is because OSPF installs the best route based on metric, regardless of the filtering applied to a single neighbor.
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 distribute-list is applied to the wrong direction; it should be outbound to filter routes being advertised.
Why it's wrong here
Inbound distribute-lists filter routes received, which should prevent installation. The issue is that the route may be learned from another source.
- ✓
The route is also learned via another OSPF neighbor that is not filtered by the distribute-list.
Why this is correct
A distribute-list only affects routes received on the specific interface. If the same route is learned from another neighbor, it will still be installed.
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 distribute-list uses an ACL that does not match the route exactly, so the route is permitted.
Why it's wrong here
If the ACL does not match, the route would be permitted by default (implicit permit), but the problem states the engineer intended to filter it.
- ✗
The distribute-list is applied after the route is already installed in the routing table, so it has no effect.
Why it's wrong here
Distribute-lists affect the installation process; they are applied before the route is added to the routing table.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the misconception that a distribute-list applied inbound on one interface will globally prevent a route from being installed, when in fact it only filters routes from that specific neighbor, and the route may still be installed from another neighbor.
Detailed technical explanation
How to think about this question
OSPF distribute-lists under the 'router ospf' process use the 'distribute-list' command with an ACL or prefix-list, and when applied inbound on an interface, they filter routes received via that specific interface only. The router maintains separate LSDB entries per neighbor, and the SPF algorithm computes routes from all LSAs; a distribute-list only prevents a route from being installed if all sources of that route are filtered. In real-world scenarios, this often happens in multi-homed OSPF designs where a route is learned from two neighbors, and the engineer applies the distribute-list to only one interface, expecting it to block the route entirely.
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.
- →
Device Access Control — study guide chapter
Learn the concepts, then practise the questions
- →
Device Access Control 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?
Device Access Control — This question tests Device Access Control — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The route is also learned via another OSPF neighbor that is not filtered by the distribute-list. — When a distribute-list is applied inbound on an OSPF interface, it filters routes received from that specific neighbor only. If the same route is also learned from another OSPF neighbor (or via a different OSPF process) that is not covered by the distribute-list, the router will still install that route from the unfiltered source. This is because OSPF installs the best route based on metric, regardless of the filtering applied to a single neighbor.
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.