Question 383 of 1,389
CCNA IP Routing Practice Question
Two routers are directly connected and running OSPF. Their IP addresses and hello timers match, but they still do not become neighbors. One side is configured for area 0 and the other for area 1 on the shared link. What is the most likely cause?
⚠ Common exam trap
A frequent exam trap is assuming that matching IP addresses and hello timers alone guarantee OSPF adjacency. Candidates often overlook the OSPF area configuration, which must be identical on both sides of a shared link. This mistake leads to confusion because the routers appear connected and can exchange packets, but OSPF adjacency never forms. The trap is focusing on interface parameters like timers or IP addressing while ignoring the fundamental requirement that both interfaces must belong to the same OSPF area to establish neighbor relationships.
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
✓
The interfaces are in different OSPF areas on the shared link.
An OSPF area mismatch is the most likely cause. In plain language, the routers may be physically connected and able to exchange packets, but OSPF still requires that both sides agree on the area associated with the shared segment. If one interface belongs to area 0 and the other belongs to area 1, the routers do not view the segment in the same OSPF context and the adjacency fails. This is a classic CCNA troubleshooting case because the addressing can look perfect while the protocol still refuses to form a neighbor relationship. OSPF is strict about several interface-level values, and the area assignment is one of the most important.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
The interfaces are in different OSPF areas on the shared link.
Why this is correct
OSPF requires that the interfaces on a directly connected link belong to the same area for the neighbour adjacency to form. In this scenario, the two routers are configured with area 0 and area 1 respectively on the shared link, which violates the OSPF rule that the area ID must match on the connecting interface. This mismatch prevents the exchange of hello packets from progressing to the 2-Way state, directly satisfying the stem’s condition that hello timers and IP addresses are correct yet adjacency fails.
- ✗
The routers need identical hostnames.
Why it's wrong here
This is wrong because hostnames do not determine OSPF adjacency.
When this WOULD be correct
In a different scenario, if the question asked about OSPF neighbor formation issues and specifically mentioned that hostname mismatches can affect certain OSPF features like authentication or logging, then this option could be correct.
- ✗
The link must be converted to a trunk.
Why it's wrong here
This is wrong because OSPF adjacency on routed interfaces does not require trunking.
When this WOULD be correct
In a different scenario where the question specifies that OSPF is being used over a network that requires VLAN segmentation, and the routers are configured on different VLANs, converting the link to a trunk would be necessary for OSPF to function properly across those VLANs.
- ✗
The routers must use static routes first.
Why it's wrong here
This is wrong because static routes are not required for OSPF adjacency formation.
When this WOULD be correct
In a different question, if the scenario described routers that were configured to use static routes exclusively and were not establishing OSPF neighbors due to misconfiguration, then the requirement for static routes could be the correct answer. For example, if the question stated that both routers were configured for static routing only and OSPF was not enabled, this option would be valid.
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.
✓The interfaces are in different OSPF areas on the shared link.Correct answer▾
Why this is correct
OSPF requires that the interfaces on a directly connected link belong to the same area for the neighbour adjacency to form. In this scenario, the two routers are configured with area 0 and area 1 respectively on the shared link, which violates the OSPF rule that the area ID must match on the connecting interface. This mismatch prevents the exchange of hello packets from progressing to the 2-Way state, directly satisfying the stem’s condition that hello timers and IP addresses are correct yet adjacency fails.
✗The routers need identical hostnames.Wrong answer — click to see why▾
Why this is wrong here
OSPF neighbor formation does not require identical hostnames; hostnames are only used for identification and do not affect OSPF operation. The routers can have any hostname and still form an adjacency as long as other OSPF parameters match.
★ When this WOULD be the correct answer
In a different scenario, if the question asked about OSPF neighbor formation issues and specifically mentioned that hostname mismatches can affect certain OSPF features like authentication or logging, then this option could be correct.
Why candidates choose this
Students might think that hostnames must match because they confuse OSPF with other protocols like EIGRP, which uses a router ID that can be derived from the hostname, or because they assume consistency in naming is required for network devices to communicate.
✗The link must be converted to a trunk.Wrong answer — click to see why▾
Why this is wrong here
OSPF operates on routed interfaces, which are Layer 3 interfaces, and does not require trunking. Trunking is a Layer 2 concept used to carry multiple VLANs over a single link, and it is not relevant to OSPF adjacency formation.
★ When this WOULD be the correct answer
In a different scenario where the question specifies that OSPF is being used over a network that requires VLAN segmentation, and the routers are configured on different VLANs, converting the link to a trunk would be necessary for OSPF to function properly across those VLANs.
Why candidates choose this
Test-takers might confuse OSPF with VLAN trunking or think that because OSPF can run over VLANs, the link must be a trunk. However, OSPF can run on access ports or routed ports without any trunk configuration.
✗The routers must use static routes first.Wrong answer — click to see why▾
Why this is wrong here
OSPF is a dynamic routing protocol that can form adjacencies and exchange routes without any static routes. Static routes are not a prerequisite for OSPF neighbor formation; OSPF uses its own hello protocol to discover neighbors.
★ When this WOULD be the correct answer
In a different question, if the scenario described routers that were configured to use static routes exclusively and were not establishing OSPF neighbors due to misconfiguration, then the requirement for static routes could be the correct answer. For example, if the question stated that both routers were configured for static routing only and OSPF was not enabled, this option would be valid.
Why candidates choose this
Some students believe that a router must have a route to the neighbor's network before forming an adjacency, but OSPF uses multicast hello packets to discover neighbors directly connected on the same link, regardless of existing routing table entries.
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.
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Last reviewed: May 17, 2026
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.
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