CCNA IP Routing Practice Question
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?
⚠ Common exam trap
Be cautious not to confuse the 2WAY state with being a BDR or DR. Understand the significance of FULL/DR and 2WAY/DROTHER states.
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
✓
This can be normal on a broadcast segment where DROTHER routers remain in 2-Way
On broadcast OSPF networks, full adjacency is typically formed with the DR and BDR. DROTHER routers can remain in the 2-Way state with one another and still be operating normally.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
R1 has failed to form adjacency with 10.1.1.3
Why it's wrong here
The 2-Way state is actually a required milestone in OSPF adjacency formation, not a failure indicator. On broadcast networks, only the DR and BDR proceed to Exchange/Loading/Full state with all routers; DROTHER routers maintain 2-Way with each other as a way to track neighbors without exchanging LSAs. Therefore, R1's relationship with 10.1.1.3 may be functioning exactly as designed.
When this WOULD be correct
In a different scenario where the question specifies that R1 is supposed to establish a full adjacency with all neighbors on a point-to-point link, and the output shows that it has not formed an adjacency with 10.1.1.3, then option A would be correct.
- ✓
This can be normal on a broadcast segment where DROTHER routers remain in 2-Way
Why this is correct
On multiaccess broadcast networks, OSPF elects a DR and BDR. Other routers (DROTHERs) only form fully adjacent neighbors with the DR and BDR; between DROTHERs, they stop at the 2-Way state because they do not exchange LSAs directly. This reduces flooding and is expected behavior, not an error.
- ✗
R1 has a duplicate router ID with 10.1.1.3
Why it's wrong here
A duplicate router ID would prevent OSPF from forming any neighbor relationship because the router ID is used as the unique identifier for each router. If R1 and 10.1.1.3 had the same router ID, OSPF would log a duplicate ID event and the adjacency would never reach even 2-Way. The presence of 2-Way indicates that Hello packets with unique router IDs have been exchanged successfully.
When this WOULD be correct
If the question stated that R1 was unable to establish any OSPF neighbor relationships at all, or if it showed that 10.1.1.3 was not listed in the OSPF neighbor table, then stating that R1 has a duplicate router ID with 10.1.1.3 would be correct, as it would prevent adjacency formation.
- ✗
The interface is passive
Why it's wrong here
A passive interface in OSPF does not send or receive Hello packets; it only advertises the network subnet as a stub. Because no Hello packets are transmitted, the router would never discover neighbors on that interface, and the neighbor table would remain empty. Seeing a neighbor ID in 2-Way proves that Hellos are being processed, so the interface cannot be passive.
When this WOULD be correct
If the question provided output indicating that the OSPF interface was configured as passive (e.g., showing no OSPF neighbors), then stating that the interface is passive would be correct. The question would need to focus on the configuration of OSPF interfaces.
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.
✓This can be normal on a broadcast segment where DROTHER routers remain in 2-WayCorrect answer▾
Why this is correct
On multiaccess broadcast networks, OSPF elects a DR and BDR. Other routers (DROTHERs) only form fully adjacent neighbors with the DR and BDR; between DROTHERs, they stop at the 2-Way state because they do not exchange LSAs directly. This reduces flooding and is expected behavior, not an error.
✗R1 has failed to form adjacency with 10.1.1.3Wrong answer — click to see why▾
Why this is wrong here
The 2-Way state is a normal OSPF neighbor state on broadcast multiaccess networks for non-DR/BDR routers (DROTHERs). It indicates that bidirectional communication has been established, but full adjacency is not required because they do not exchange LSAs directly. This is not a failure.
★ When this WOULD be the correct answer
In a different scenario where the question specifies that R1 is supposed to establish a full adjacency with all neighbors on a point-to-point link, and the output shows that it has not formed an adjacency with 10.1.1.3, then option A would be correct.
Why candidates choose this
Students often associate the 2-Way state with incomplete adjacency or a problem, but in OSPF, 2-Way is a valid state for DROTHERs on broadcast segments. They may confuse it with the INIT or EXSTART states, which indicate issues.
✗R1 has a duplicate router ID with 10.1.1.3Wrong answer — click to see why▾
Why this is wrong here
A duplicate router ID would cause OSPF neighbor state to oscillate or remain in EXSTART/EXCHANGE, not stabilize in 2-Way. The output shows a stable 2-Way state, which is normal for DROTHERs. Duplicate IDs would also generate error messages in the logs.
★ When this WOULD be the correct answer
If the question stated that R1 was unable to establish any OSPF neighbor relationships at all, or if it showed that 10.1.1.3 was not listed in the OSPF neighbor table, then stating that R1 has a duplicate router ID with 10.1.1.3 would be correct, as it would prevent adjacency formation.
Why candidates choose this
Test-takers might think that any unusual neighbor state (like 2-Way) indicates a duplicate ID, but 2-Way is actually a normal state for non-DR/BDR neighbors. They may confuse the 2-Way state with the DOWN or ATTEMPT states that occur with duplicate IDs.
✗The interface is passiveWrong answer — click to see why▾
Why this is wrong here
A passive interface in OSPF does not send Hello packets and therefore cannot form any neighbor adjacency. The output shows two neighbors in valid states (FULL and 2-Way), which proves the interface is active and sending Hellos.
★ When this WOULD be the correct answer
If the question provided output indicating that the OSPF interface was configured as passive (e.g., showing no OSPF neighbors), then stating that the interface is passive would be correct. The question would need to focus on the configuration of OSPF interfaces.
Why candidates choose this
Students may think that a passive interface prevents full adjacency, but it actually prevents any adjacency at all. The presence of neighbors in the output contradicts the passive interface assumption.
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?”
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
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OSPFv3 Single-Area Configuration for IPv6
Key term
OSPF neighbor
An OSPF neighbor is another router that has been directly discovered through OSPF Hello packets and is willing to exchange routing information to build a network topology map.
Key term
CAN
A CAN (Controller Area Network) is a robust vehicle bus standard designed to allow microcontrollers and devices to communicate with each other without a host computer.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 200-301 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 200-301 exam.