Question 754 of 1,819
IP RoutinghardMultiple ChoiceObjective-mapped

CCNA IP Routing Practice Question

This 200-301 practice question tests your understanding of ip routing. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. A key principle to apply: oSPF uses neighbor relationships to exchange routing information and build a consistent link-state database across routers.. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.

Exhibit

R1#
router ospf 1
 network 10.1.12.0 0.0.0.255 area 0
!
interface GigabitEthernet0/0
 ip address 10.1.12.1 255.255.255.0

You are verifying OSPF operation on router R1. After confirming that OSPF is configured on the correct interfaces, which command should you use next to directly check whether R1 has established a neighbor adjacency with another OSPF router?

Clue words in this question

Noticing these words before you look at the options changes how you read each choice.

  • Clue: "which command"

    Why it matters: Tests specific CLI syntax. Recall the exact command and its required context — near-synonyms and partial matches are common distractors.

Question 1hardmultiple choice
Review the full OSPF breakdown →

Exhibit

R1#
router ospf 1
 network 10.1.12.0 0.0.0.255 area 0
!
interface GigabitEthernet0/0
 ip address 10.1.12.1 255.255.255.0

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 ip ospf neighbor

The command show ip ospf neighbor directly displays the OSPF neighbor table, showing whether an adjacency has formed, the neighbor's Router ID, and the current state (e.g., FULL). This is the quickest verification step after confirming configurations. The other commands are unrelated to OSPF: show vlan brief displays VLAN assignments, show spanning-tree shows STP topology, and show mac address-table shows the MAC address table. None of these provide any OSPF neighbor information and would only delay troubleshooting.

Key principle: OSPF uses neighbor relationships to exchange routing information and build a consistent link-state database across routers.

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 ip ospf neighbor

    Why this is correct

    This is correct because it directly shows OSPF adjacency and neighbor state.

    Clue confirmation

    The clue word "which command" in the question point toward this answer.

    Related concept

    OSPF uses neighbor relationships to exchange routing information and build a consistent link-state database across routers.

  • show vlan brief

    Why it's wrong here

    This is wrong because VLAN output does not verify OSPF neighbor state.

    When this WOULD be correct

    In a question focused on verifying VLAN configurations or troubleshooting Layer 2 connectivity issues, 'show vlan brief' would be the correct command to check if the VLANs are properly set up and operational.

  • show spanning-tree

    Why it's wrong here

    This is wrong because STP output is not the primary verification tool for OSPF adjacency.

    When this WOULD be correct

    In a different scenario where the question asks for a command to troubleshoot Layer 2 connectivity issues or to verify the status of STP on a switch, 'show spanning-tree' would be the correct answer, as it provides insights into the spanning tree status and potential issues affecting VLANs.

  • show mac address-table

    Why it's wrong here

    This is wrong because MAC table output does not verify OSPF neighbor relationships.

    When this WOULD be correct

    If the exam question asked about verifying MAC address learning on a switch or troubleshooting Layer 2 connectivity issues, then 'show mac address-table' would be the correct command to use in that context.

Option-by-option analysis

Why each answer is right or wrong

Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The 200-301 exam frequently reuses these exact scenarios with slightly different constraints.

show ip ospf neighborCorrect answer

Why this is correct

This is correct because it directly shows OSPF adjacency and neighbor state.

show vlan briefWrong answer — click to see why

Why this is wrong here

The 'show vlan brief' command displays VLAN information and port assignments, which is unrelated to OSPF neighbor relationships. OSPF operates at Layer 3 and does not depend on VLAN details for adjacency verification.

★ When this WOULD be the correct answer

In a question focused on verifying VLAN configurations or troubleshooting Layer 2 connectivity issues, 'show vlan brief' would be the correct command to check if the VLANs are properly set up and operational.

Why candidates choose this

A student might think that since OSPF runs over IP, checking VLANs could be relevant if OSPF is configured on a VLAN interface (SVI). However, this command does not show OSPF-specific neighbor state or adjacency information.

show spanning-treeWrong answer — click to see why

Why this is wrong here

The 'show spanning-tree' command provides information about the Spanning Tree Protocol (STP) state of ports, which is a Layer 2 function. OSPF adjacency verification requires Layer 3 neighbor state information, not STP topology.

★ When this WOULD be the correct answer

In a different scenario where the question asks for a command to troubleshoot Layer 2 connectivity issues or to verify the status of STP on a switch, 'show spanning-tree' would be the correct answer, as it provides insights into the spanning tree status and potential issues affecting VLANs.

Why candidates choose this

A student might confuse STP with OSPF because both involve 'neighbor' concepts (STP has designated/root ports, OSPF has neighbor states). However, STP does not show OSPF adjacency details.

show mac address-tableWrong answer — click to see why

Why this is wrong here

The 'show mac address-table' command displays MAC address entries learned by the switch, which is Layer 2 information. OSPF neighbor relationships are Layer 3 and require IP-based commands to verify.

★ When this WOULD be the correct answer

If the exam question asked about verifying MAC address learning on a switch or troubleshooting Layer 2 connectivity issues, then 'show mac address-table' would be the correct command to use in that context.

Why candidates choose this

A student might think that since OSPF packets are encapsulated in Ethernet frames, checking the MAC table could help verify that OSPF hello packets are being received. However, the MAC table does not indicate OSPF neighbor state or adjacency formation.

Analysis generated from the official 200-301blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”

Common exam traps

Common exam trap: answer the scenario, not the keyword

Avoid confusing route visibility with neighbor status; they are related but distinct concepts.

Trap categories for this question

  • Command / output trap

    This is wrong because VLAN output does not verify OSPF neighbor state.

Detailed technical explanation

How to think about this question

Open Shortest Path First (OSPF) is a link-state routing protocol that relies on establishing neighbor relationships between routers to exchange routing information. These neighbor relationships are formed through a series of protocol states, culminating in a 'Full' adjacency where routers have synchronized their link-state databases. The 'show ip ospf neighbor' command is the definitive way to verify these neighbor states on Cisco devices, providing detailed information about each OSPF neighbor, including their IP address, interface, state, and dead timer. When troubleshooting or verifying OSPF operation, it is crucial to confirm that neighbor adjacencies exist before expecting routes to be exchanged. The decision to use 'show ip ospf neighbor' comes from understanding that OSPF adjacency formation is a prerequisite for routing updates. Other commands like 'show vlan brief' or 'show spanning-tree' focus on Layer 2 infrastructure and do not provide any information about Layer 3 routing protocol status. Similarly, 'show mac address-table' only shows MAC address mappings and is unrelated to OSPF neighbor formation. A common exam trap is to confuse Layer 2 verification commands with routing protocol verification. For example, students might incorrectly choose 'show vlan brief' or 'show spanning-tree' thinking that Layer 2 connectivity guarantees OSPF adjacency. However, OSPF adjacency depends on correct Layer 3 configuration and protocol negotiation, not just Layer 2 connectivity. Practically, even if Layer 2 is operational, OSPF neighbors may fail to form due to mismatched hello intervals, area IDs, or authentication settings, which only 'show ip ospf neighbor' can reveal.

KKey Concepts to Remember

  • OSPF uses neighbor relationships to exchange routing information and build a consistent link-state database across routers.
  • The command 'show ip ospf neighbor' directly displays the current OSPF neighbor adjacency states and is the primary verification tool for OSPF relationships.
  • VLAN information shown by 'show vlan brief' relates to Layer 2 segmentation and does not provide any insight into OSPF neighbor status or routing adjacency.
  • Spanning Tree Protocol (STP) manages Layer 2 loop prevention and does not influence or verify Layer 3 OSPF neighbor relationships.
  • The MAC address table shows Layer 2 address mappings and does not indicate OSPF neighbor formation or routing protocol status.
  • Verifying OSPF neighbor adjacency is essential before troubleshooting routing issues because adjacency confirms that routers can exchange OSPF LSAs.
  • OSPF neighbor states include Down, Init, Two-Way, ExStart, Exchange, Loading, and Full, with 'Full' indicating a fully formed adjacency.
  • Using the correct verification command helps isolate routing protocol issues quickly and prevents misdiagnosing Layer 2 or unrelated problems.

TExam Day Tips

  • Watch for words such as best, first, most likely and least administrative effort.
  • Review why wrong options are wrong, not only why the correct option is correct.

Key takeaway

OSPF uses neighbor relationships to exchange routing information and build a consistent link-state database across routers.

Real-world example

How this comes up in practice

A network engineer at a university connects two campus buildings via a fibre link. Both routers run OSPF, but no adjacency forms — even though both routers can ping each other. The engineer finds one router is in area 0 and the other in area 1. OSPF adjacency requires matching area numbers, hello/dead timers, and network type. IP reachability alone is not enough.

What to study next

Got this wrong? Here's your next step.

Review oSPF uses neighbor relationships to exchange routing information and build a consistent link-state database across routers., then practise related 200-301 questions on the same topic to reinforce the concept.

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FAQ

Questions learners often ask

What does this 200-301 question test?

IP Routing — This question tests IP Routing — OSPF uses neighbor relationships to exchange routing information and build a consistent link-state database across routers..

What is the correct answer to this question?

The correct answer is: show ip ospf neighbor — The command show ip ospf neighbor directly displays the OSPF neighbor table, showing whether an adjacency has formed, the neighbor's Router ID, and the current state (e.g., FULL). This is the quickest verification step after confirming configurations. The other commands are unrelated to OSPF: show vlan brief displays VLAN assignments, show spanning-tree shows STP topology, and show mac address-table shows the MAC address table. None of these provide any OSPF neighbor information and would only delay troubleshooting.

What should I do if I get this 200-301 question wrong?

Review oSPF uses neighbor relationships to exchange routing information and build a consistent link-state database across routers., then practise related 200-301 questions on the same topic to reinforce the concept.

Are there clue words in this question I should notice?

Yes — watch for: "which command". Tests specific CLI syntax. Recall the exact command and its required context — near-synonyms and partial matches are common distractors.

What is the key concept behind this question?

OSPF uses neighbor relationships to exchange routing information and build a consistent link-state database across routers.

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Last reviewed: May 17, 2026

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