hardMultiple ChoiceObjective-mapped
300-410 Practice Question: An engineer configures OSPFv3 with a filter-list…
An engineer configures OSPFv3 with a filter-list on an ABR to filter prefixes. After configuration, the routes are still being advertised. Which is the most likely explanation?
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 filter-list only filters inter-area prefixes, not external routes.
In OSPFv3, prefix filtering is done using the 'prefix-list' or 'filter-list' command under the area. However, the filter-list in OSPFv3 filters type 3 LSAs (inter-area prefixes) but not type 5 LSAs (external routes). If the routes being advertised are external, the filter-list will not affect them.
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 filter-list only filters inter-area prefixes, not external routes.
Why this is correct
Filter-list in OSPFv3 applies to type 3 LSAs only, not type 5 LSAs.
- ✗
The filter-list is applied to the wrong area.
Why it's wrong here
Even if applied correctly, it would not filter external routes.
- ✗
The filter-list uses an incorrect prefix-list.
Why it's wrong here
The prefix-list may be correct, but filter-list does not affect external routes.
- ✗
The OSPFv3 process needs to be restarted.
Why it's wrong here
Restarting OSPFv3 would not change the behavior for external routes.
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.
Go deeper
Related to this question
Learn chapter
OSPF Route Summarization and Filtering
Key term
IPv6 Routing OSPFv3
OSPFv3 is a routing protocol that lets routers share information about how to reach destinations in an IPv6 network, updating routes automatically as the network changes.
Key term
BGP Prefix Filtering
BGP Prefix Filtering is the practice of controlling which network routes (prefixes) a router accepts or advertises to its BGP neighbors, preventing unwanted or harmful routes from spreading across the internet.
About these practice questions
One of 1,966 original 300-410 practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
JA
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.