CCNA Network Services and Security Practice Question
A host can reach other devices on its local subnet, but it cannot reach remote networks. The host has a valid IP address and subnet mask. Which missing item is the strongest suspect?
⚠ Common exam trap
A common exam trap is selecting options related to routing protocols like OSPF or Layer 2 technologies such as STP or VLANs when the issue is actually a missing default gateway. Candidates might incorrectly assume that the host needs an OSPF process ID or STP priority to reach remote networks. However, hosts do not run routing protocols and do not participate in STP decisions. The real problem is the absence of default gateway information, which prevents the host from forwarding packets beyond its local subnet. Misunderstanding this leads to incorrect answers that focus on advanced protocols rather than basic IP configuration.
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
✓
Default gateway information
The strongest suspect is a missing default gateway. In practical terms, the host can still identify and reach local addresses because it has its own IP and subnet mask. But without a default gateway, it has no next hop for destinations outside the local subnet. That is why local communication works while remote communication fails. This is one of the most common host-configuration troubleshooting patterns on the exam and in real networks.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Default gateway information
Why this is correct
A host reaches its local subnet because it can ARP for those destinations, but for any address outside that subnet, it must forward the packet to a router. Without a default gateway, the host has no next-hop IP address, so it drops or returns an error for all off-subnet traffic. The default gateway is the router interface on the host's subnet, and missing it precisely matches the symptom of local reachability but remote unreachability.
- ✗
STP priority information
Why it's wrong here
STP priority is a switch-level parameter used in Spanning Tree Protocol to elect a root bridge and prevent loops in Layer 2 topology. End hosts are not participants in STP and never consult priority information to forward packets. Therefore, missing STP priority would have no direct effect on a host's capability to send traffic off-subnet; it would only influence switch port states or redundancy behavior.
When this WOULD be correct
In a scenario where the question asks about issues related to Layer 2 network topology and redundancy, a question could state that a network is experiencing broadcast storms or connectivity issues due to improper STP configuration. In that case, the STP priority information would be the correct focus for troubleshooting.
- ✗
A voice VLAN setting
Why it's wrong here
A voice VLAN is a Layer 2 mechanism used on switch ports to separate voice and data traffic for IP phones. The symptom describes a Layer 3 reachability failure, not an issue with phone registration or 802.1Q tagging. An end host that can reach local devices but not remote networks has a routing problem, not a missing voice VLAN configuration on the access port.
When this WOULD be correct
In a question asking about issues with voice traffic on a network, where a host can communicate locally but experiences problems with voice quality or connectivity, a missing voice VLAN setting could be the correct answer if the question specifies that voice traffic is not being prioritized or routed correctly.
- ✗
An OSPF process ID
Why it's wrong here
OSPF process ID is a locally significant identifier on a router for a distinct OSPF routing process; it is irrelevant to end hosts. A host uses its default gateway as the next hop and does not run dynamic routing protocols to decide off-subnet forwarding. Consequently, an OSPF process ID could not be the cause of a host reaching local devices but failing to reach remote networks.
When this WOULD be correct
In a question where a network administrator is troubleshooting routing issues on a router and needs to ensure that OSPF is correctly configured, a missing or incorrect OSPF process ID could prevent the router from participating in OSPF routing, leading to connectivity issues with remote networks.
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.
✓Default gateway informationCorrect answer▾
Why this is correct
A host reaches its local subnet because it can ARP for those destinations, but for any address outside that subnet, it must forward the packet to a router. Without a default gateway, the host has no next-hop IP address, so it drops or returns an error for all off-subnet traffic. The default gateway is the router interface on the host's subnet, and missing it precisely matches the symptom of local reachability but remote unreachability.
✗STP priority informationWrong answer — click to see why▾
Why this is wrong here
STP (Spanning Tree Protocol) priority information is related to the selection of the root bridge in a Layer 2 network and does not affect the ability of a host to reach remote networks. The issue described in the question pertains to Layer 3 connectivity, which is not influenced by STP settings.
★ When this WOULD be the correct answer
In a scenario where the question asks about issues related to Layer 2 network topology and redundancy, a question could state that a network is experiencing broadcast storms or connectivity issues due to improper STP configuration. In that case, the STP priority information would be the correct focus for troubleshooting.
Why candidates choose this
Candidates may be tempted by this option because they recognize STP as a critical component of network design and may mistakenly associate it with connectivity issues, thinking that any Layer 2 setting could impact Layer 3 communication.
✗A voice VLAN settingWrong answer — click to see why▾
Why this is wrong here
A voice VLAN setting is not relevant to the issue of a host being unable to reach remote networks, as VLAN configurations primarily affect local traffic segmentation rather than routing capabilities.
★ When this WOULD be the correct answer
In a question asking about issues with voice traffic on a network, where a host can communicate locally but experiences problems with voice quality or connectivity, a missing voice VLAN setting could be the correct answer if the question specifies that voice traffic is not being prioritized or routed correctly.
Why candidates choose this
Candidates may confuse VLAN settings with routing issues, thinking that if local communication is fine, VLAN configurations could still impact overall network performance, especially in environments where voice traffic is critical.
✗An OSPF process IDWrong answer — click to see why▾
Why this is wrong here
An OSPF process ID is used to identify OSPF routing processes on a router, but it does not affect a host's ability to reach remote networks directly. The issue described in the question pertains to layer 3 connectivity, which is not influenced by OSPF settings on a host.
★ When this WOULD be the correct answer
In a question where a network administrator is troubleshooting routing issues on a router and needs to ensure that OSPF is correctly configured, a missing or incorrect OSPF process ID could prevent the router from participating in OSPF routing, leading to connectivity issues with remote networks.
Why candidates choose this
Candidates may be tempted by this option because OSPF is a well-known routing protocol, and they might mistakenly associate it with connectivity issues, thinking that any routing-related configuration could be relevant to the problem presented.
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
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Key term
Default gateway
A default gateway is a network device, typically a router, that acts as the exit point for traffic from a local network to other networks, including the internet.
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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JA
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.