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300-410 Practice Question: An engineer is troubleshooting an OSPFv2…
An engineer is troubleshooting an OSPFv2 adjacency that remains stuck in EXSTART state. Which TWO actions should the engineer take to resolve the issue? (Choose TWO.)
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
✓
Verify that the MTU on both interfaces is identical.
An EXSTART state indicates a problem with the Database Description (DD) packet exchange, often due to MTU mismatch or mismatched interface MTU values. Also, mismatched OSPF network types can cause DD packet issues. The other options are either unrelated or incorrect.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Verify that the MTU on both interfaces is identical.
Why this is correct
Correct. An MTU mismatch can prevent DD packets from being exchanged properly, causing the adjacency to stay in EXSTART.
- ✗
Ensure that the OSPF hello and dead intervals match on both routers.
Why it's wrong here
Incorrect. Mismatched hello/dead intervals cause the adjacency to stick in INIT or 2-WAY, not EXSTART.
- ✓
Check that the OSPF network type is the same on both interfaces.
Why this is correct
Correct. Mismatched network types (e.g., broadcast vs. point-to-point) can lead to DD packet negotiation failures, causing EXSTART.
- ✗
Confirm that the OSPF router IDs are unique across the network.
Why it's wrong here
Incorrect. Duplicate router IDs cause the adjacency to flap or fail to form, but typically not a stuck EXSTART.
- ✗
Increase the OSPF retransmit interval on both routers.
Why it's wrong here
Incorrect. The retransmit interval affects retransmission of LSAs, not the DD exchange process that occurs in EXSTART.
Visual reference
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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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.