JN0-106 Routing Fundamentals Practice Question
A network administrator is troubleshooting a missing route in the routing table. The route is learned via OSPF, and the OSPF neighbor adjacency is up. Which command would help determine if OSPF received the route?
⚠ Common exam trap
A common mix-up: candidates confuse 'show route protocol ospf' (which shows installed routes) with 'show ospf database' (which shows received LSAs), leading them to pick option A when the route is missing from the routing table but still present in the LSDB.
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
✓
show ospf database
The OSPF link-state database (LSDB) contains all received LSAs, including Type 1 (Router) and Type 3 (Summary) LSAs that advertise routes. Even if a route is not installed in the routing table (e.g., due to a higher administrative distance or a missing route preference), the 'show ospf database' command confirms whether OSPF has received the LSA carrying that route. This directly answers the question of whether OSPF received the route, independent of route installation.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
show route protocol ospf
Why it's wrong here
In Junos, 'show route protocol ospf' displays only the active OSPF routes that have been selected and placed into the routing table, not every route received or advertised. Routes hidden due to higher preference, unreachable next hops, or import policy are omitted. Therefore, if the OSPF LSA exists but the route is not installed, this command will not provide the needed diagnostic insight.
- ✗
show ospf neighbor
Why it's wrong here
This command focuses on the state of OSPF neighbor adjacencies, such as Full or ExStart, and verifies hello timers, dead intervals, and area membership. It does not expose the contents of LSAs or the prefix information learned from those neighbors. A missing route can occur even when all neighbors show Full, so this command cannot directly confirm whether a specific prefix was received.
- ✓
show ospf database
Why this is correct
The OSPF database command reveals the link-state advertisements (LSAs) stored in the router's OSPF LSDB, including Router, Network, and Summary LSAs that contain the actual prefix information. This is the authoritative source to verify whether a route's LSA has been received and is present in the network topology. If the prefix appears here but not in the routing table, the troubleshooting focus shifts to route selection or policy, making this the correct diagnostic step.
- ✗
show interface terse
Why it's wrong here
This command displays the administrative and operational status of interfaces, along with their configured IP addresses and protocol flags, but it carries no OSPF-specific state or route information. Checking interface terse only tells you whether the physical or logical interfaces are up, not whether OSPF has learned or processed any routes. The missing route would not be visible here, and an interface being down alone does not explain an OSPF LSA's absence from the database.
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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About these practice questions
Courseiva writes every JN0-106 question from scratch — 156 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This JN0-106 practice question is part of Courseiva's free Juniper Networks 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 JN0-106 exam.