hardMultiple Choice
300-410 Practice Question: Runs the following command to troubleshoot OSPF…
A network engineer runs the following command to troubleshoot OSPF route redistribution:
R1# show ip ospf database external 5.5.5.5
OSPF Router with ID (1.1.1.1) (Process ID 1)
Type-5 AS External Link States
LS age: 120 Options: (No TOS-capability, DC, Upward) LS Type: AS External Link Link State ID: 5.5.5.5 (External Network Number) Advertising Router: 3.3.3.3 LS Seq Number: 80000001 Checksum: 0xABCD Length: 36 Network Mask: /32 Metric Type: 2 (Larger than any link state path) TOS: 0 Metric: 20 Forward Address: 0.0.0.0 External Route Tag: 0
What does this output indicate?
⚠ Common exam trap
The trap is misreading the Forward Address field — candidates often assume 0.0.0.0 means the destination itself, when it actually means 'use the advertising ASBR as next-hop,' and they may also confuse Type-5 external LSAs with Type-4 ASBR summary LSAs.
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 was redistributed into OSPF by router 3.3.3.3 with a metric of 20.
The output shows a Type-5 AS External LSA for 5.5.5.5/32, advertised by router 3.3.3.3, with Metric Type 2 and a metric of 20. This means 3.3.3.3 (an ASBR) redistributed the external prefix into OSPF, and the cost of 20 is the external metric carried in the LSA. The Forward Address of 0.0.0.0 indicates the route should be reached via the advertising ASBR itself.
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 prefix 5.5.5.5/32 is a network inside the OSPF domain.
Why it's wrong here
The Type-5 AS External LSA with Advertising Router 3.3.3.3 and Metric Type 2 describes a prefix redistributed into OSPF from outside the domain, not an internal network. It is tempting because the Link State ID resembles an internal prefix, but Type-5 LSAs by definition originate externally.
- ✓
The route was redistributed into OSPF by router 3.3.3.3 with a metric of 20.
Why this is correct
The Type-5 AS External Link State Advertised by Advertising Router 3.3.3.3 confirms that router originated the redistribution, while Metric Type 2 with Metric 20 shows the external cost assigned. The Forward Address of 0.0.0.0 means traffic reaches 5.5.5.5 via the advertising router itself, satisfying the stem's redistribution query.
- ✗
The forward address indicates the next-hop is 5.5.5.5.
Why it's wrong here
The Forward Address field reads 0.0.0.0, meaning the forwarding next hop is the Advertising Router (3.3.3.3), not 5.5.5.5, which is only the Link State ID naming the external prefix. It is tempting because the prefix value appears prominent in the output.
- ✗
This is a Type 4 Summary ASBR LSA.
Why it's wrong here
The output explicitly shows LS Type: AS External Link, a Type 5 LSA originated by an ASBR, not a Type 4 Summary ASBR LSA. It is tempting because both are ASBR-related and generated by boundary routers, but Type 4 is flooded only within an area by an ABR.
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.
Go deeper
Related to this question
Learn chapter
OSPF Neighbor Adjacency and Basics
Key term
Route Redistribution Between Protocols
Route redistribution between protocols is the process of taking routes learned from one routing protocol and injecting them into another routing protocol so that networks using different protocols can communicate.
About these practice questions
This 300-410 question is part of Courseiva's 1,401-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam dumps. Learn why practice questions differ from exam dumps →
JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Cisco exam blueprint
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.