Question 1hardmultiple choice
Full question →hardmultiple choiceObjective-mapped
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
Based on the exhibit, which command is the best next step to verify whether R1 has formed an OSPF neighbor relationship?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Best answer
show ip ospf neighbor
This is correct because it directly shows OSPF adjacency and neighbor state.
B
Distractor review
show vlan brief
This is wrong because VLAN output does not verify OSPF neighbor state.
C
Distractor review
show spanning-tree
This is wrong because STP output is not the primary verification tool for OSPF adjacency.
D
Distractor review
show mac address-table
This is wrong because MAC table output does not verify OSPF neighbor relationships.
Common exam trap
Common exam trap: answer the scenario, not the keyword
A frequent exam trap is selecting a Layer 2 command like 'show vlan brief' or 'show spanning-tree' to verify OSPF neighbor relationships. Candidates may assume that Layer 2 connectivity automatically means OSPF adjacency exists. However, OSPF is a Layer 3 routing protocol that requires specific protocol negotiation and matching parameters to form neighbors. Using Layer 2 commands only confirms physical or data link connectivity, not OSPF adjacency. This mistake wastes time and leads to incorrect troubleshooting steps, as OSPF neighbor formation depends on protocol-specific states visible only with 'show ip ospf neighbor'.
Technical deep dive
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.
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More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
Question 1
A router learns the same prefix from both OSPF and EIGRP. Which route is installed by default?
Question 2
A router shows this output: R1#show ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface 10.1.1.2 1 FULL/DR 00:00:34 192.168.12.2 GigabitEthernet0/0 10.1.1.3 1 2WAY/DROTHER 00:00:39 192.168.12.3 GigabitEthernet0/0 Which statement is correct?
Question 3
What is the OSPF metric called?
Question 4
A non-root switch has two uplinks toward the root bridge. One path has a lower total STP cost than the other. What role will the lower-cost uplink have?
Question 5
A router interface applies this ACL inbound: 10 deny tcp any any eq 80 20 permit ip any any A user reports that web browsing to a server by IP address fails, but ping works. Which statement best explains the behavior?
Question 6
A router learns route 198.51.100.0/24 from OSPF with AD 110 and also has a static route to the same prefix configured with AD 150. Which route is installed?
FAQ
Questions learners often ask
What does this 200-301 question test?
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 best next step is to use the command that directly displays OSPF neighbor status. In practical terms, after reviewing interface and process configuration, the fastest way to confirm whether adjacency exists is to check the OSPF neighbor table rather than guessing from routing behavior alone. This is a simulation-style question because it asks for the best verification step after examining configuration context.
What should I do if I get this 200-301 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
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