How should I use these OSPF practice questions?

Read each scenario carefully and choose your answer before revealing the explanation. Then check why your choice was right or wrong. Repeat until the reasoning feels automatic.

Can I practise just OSPF questions in a focused session?

Yes — use the session launcher on this page to start a 10-, 20-, 30- or 50-question session drawn entirely from the OSPF domain.

JNCIS-ENT · topic practice

OSPF practice questions

Practise JNCIS-ENT Juniper Networks Enterprise Routing and Switching, Specialist (JNCIS-ENT, JN0-352) (JNCIS-ENT) OSPF questions covering neighbour states, router IDs, areas, timers, passive interfaces, OSPF cost, route selection, and command-output troubleshooting.

Courseiva uses original exam-style practice questions designed for learning and revision. The goal is to understand the concepts, recognise exam patterns, and improve through explanations — not memorise copied exam dumps.

Reviewed byJohnson Ajibi· MSc IT Security

20 questionsDomain: OSPF

Practice 10 questions Browse domain →

What the exam tests

What to know about OSPF

OSPF questions usually test neighbour formation, areas, router IDs, route preference, metrics and command-output interpretation.

How OSPF neighbours form and why adjacency can fail.

How router ID, area ID, timers, passive interfaces and authentication affect OSPF.

How OSPF cost influences route selection.

How to read show ip route and show ip ospf neighbor output.

Why learners struggle

Why OSPF questions are commonly missed

OSPF questions are often missed because learners confuse neighbour states, route selection rules, router IDs, areas, timers, and cost calculations. A question may look like it is testing OSPF, but the real decision may depend on administrative distance, route specificity, passive interfaces, DR/BDR behaviour, or command-output interpretation.

·OSPF cost vs administrative distance — they measure different things and compare differently
·2-Way vs FULL neighbour state — 2-Way is not always a failed adjacency
·DR vs BDR vs DROTHER — election depends on network type and interface priority
·Area mismatch vs timer mismatch — both prevent adjacency but for different reasons
·Passive interface vs failed adjacency — passive interfaces intentionally suppress hello packets
·Router ID selection — highest loopback address wins unless manually configured
·show ip route OSPF codes — O, O IA, O E1, O E2 describe different route sources
·OSPF external route types — E1 accumulates cost, E2 preserves the external cost only

Watch out for

Common OSPF exam traps

▸A matching network statement does not guarantee adjacency.
▸OSPF cost and administrative distance solve different problems.
▸Router ID may come from a loopback or manual configuration.
▸A route can exist in OSPF but still not become the installed route.

Practice set

OSPF questions

20 questions · select your answer, then reveal the explanation

Question 1mediummultiple choice

OSPF practice questions

What to know about OSPF

Why OSPF questions are commonly missed

Common OSPF exam traps

OSPF questions

While reviewing OSPF logs on a Junos device, you notice frequent adjacency flaps. You suspect a mismatch in the OSPF timer configurations. Which two timers must match identically on adjacent OSPF interfaces for an adjacency to form?

You need to configure an OSPF interface as passive on a Junos routing platform so that it advertises connected subnets without sending OSPF hello packets. Which configuration command achieves this?

Which THREE conditions must match between neighboring OSPF routers for an adjacency to successfully transition from Init to ExStart/Exchange? (Choose three)

Which THREE Junos configuration elements are required when setting up OSPF authentication using MD5 on a broadcast interface? (Choose three)

Which TWO factors directly influence the calculation of the OSPF Shortest Path First (SPF) algorithm tree? (Choose two)

Which command allows an administrator to view the OSPF link-state database (LSDB) summary on a Junos device?

An engineer needs to prevent Type 4 and Type 5 LSAs from entering a specific OSPF area while still allowing external routes to be summarized via default routing. Which area type should be configured?

You are troubleshooting an OSPF adjacency issue between two Juniper EX Series switches. One switch logs an error stating 'OSPF packet received with mismatched area ID'. Where in the Junos CLI should you check and correct this parameter?

Which OSPF packet type is responsible for discovering neighbors and maintaining adjacencies on a Junos device?

You are configuring an OSPF interface on a Junos router and want to ensure that the interface never participates in DR/BDR election, always acting as a point-to-point connection. Which interface type should you explicitly configure?

An administrator is configuring OSPF on a Junos device and notices that two routers on a broadcast segment are stuck in the 2-Way state. What is the most likely cause of this behavior on a broadcast network?

An OSPF network running on Junos has multiple equal-cost paths to a destination. By default, how many equal-cost paths does Junos OSPF install into the forwarding table (inet.0)?

Which LSA type is originated by a Designated Router (DR) on a broadcast or NBMA network to describe all the routers attached to that multi-access segment?

What type of LSA is generated by an OSPF Area Border Router (ABR) to advertise networks from one area to another area?

You are configuring OSPF route summarization on an ABR in a Junos environment. You want to summarize routes from Area 1 into Area 0. Which Junos configuration hierarchy is used to define this summary?

When calculating OSPF path costs in a network containing high-speed links (such as 10Gbps and 40Gbps interfaces), what default reference bandwidth does Junos use, and what configuration adjustment is typically required to differentiate costs accurately?

You are troubleshooting an OSPF network where an ASBR is injecting external routes. Routers in other areas need to reach this ASBR. Which LSA type provides the reachability information to the ASBR itself?

Which OSPF packet type is used to acknowledge the receipt of Link-State Updates (LSUs) to ensure reliable flooding?

An administrator needs to modify the OSPF cost on a specific Junos interface to influence traffic engineering without changing the reference bandwidth globally. Which command accomplishes this?

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Frequently asked questions

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Study resources

Exam traps to avoid