CCNA Switching and Network Access Practice Question
A network technician is troubleshooting an inter-VLAN routing issue on a multilayer switch. Hosts on VLAN 10 can reach the SVI for VLAN 10 (10.0.10.1) but cannot reach hosts on VLAN 20. The technician has verified that 'ip routing' is enabled and that the 'show ip route' command displays directly connected routes for both VLANs. No static routes are configured. What should the technician do next?
⚠ Common exam trap
Cisco often tests the misconception that if 'ip routing' is enabled and routes are present, inter-VLAN routing should work, but they trap candidates by omitting the critical step of ARP resolution, which is required to deliver frames to the destination host's MAC address.
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
✓
Check the ARP table for entries on VLAN 20.
The hosts on VLAN 10 can reach the SVI (10.0.10.1) but not hosts on VLAN 20, which indicates that Layer 3 routing is working (ip routing enabled, directly connected routes present). The issue is likely that the switch does not have the MAC address of the destination host in VLAN 20 in its ARP table, so it cannot forward frames to that host. Checking the ARP table for VLAN 20 entries will reveal whether the switch has resolved the Layer 3-to-Layer 2 address mapping for the destination.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Check the ARP table for entries on VLAN 20.
Why this is correct
The Layer 3 routing table is correct; the problem is likely that the switch lacks a Layer 2 MAC address for the destination host on VLAN 20. Examining the ARP cache will confirm whether the switch can map the destination IP to a MAC address, and if not, will show that ARP resolution is failing, which explains the connectivity break.
- ✗
Issue the 'show ip routing' command again to confirm routing is enabled.
Why it's wrong here
The technician has already verified that 'ip routing' is enabled and that the routing table contains the necessary connected routes. Repeating this check does not advance the troubleshooting process and ignores the likely Layer 2 issue.
- ✗
Configure a default route pointing to the next-hop gateway.
Why it's wrong here
Configuring a default route is irrelevant here because both VLANs are directly connected subnets on the multilayer switch. The routing table already contains connected routes for VLAN 20, so traffic to that subnet is forwarded using the connected route, not a default route. Adding a default route would only affect traffic destined for external networks, and it would not resolve the underlying failure to resolve the destination host's MAC address via ARP. In fact, introducing a default route without addressing the ARP issue could mask the problem or create a less-specific routing entry that interferes with normal forwarding.
- ✗
Verify the VLAN membership of the destination host on VLAN 20.
Why it's wrong here
Although a mismatched VLAN could cause a connectivity problem, the scenario explicitly identifies the destination hosts as being on VLAN 20. The issue is between VLANs, not within a VLAN, and the Layer 3 information (connected route for VLAN 20) suggests the switch has an interface in that subnet. Checking ARP is more immediate and diagnostic than re-verifying VLAN assignment.
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.
✓Check the ARP table for entries on VLAN 20.Correct answer▾
Why this is correct
The Layer 3 routing table is correct; the problem is likely that the switch lacks a Layer 2 MAC address for the destination host on VLAN 20. Examining the ARP cache will confirm whether the switch can map the destination IP to a MAC address, and if not, will show that ARP resolution is failing, which explains the connectivity break.
✗Issue the 'show ip routing' command again to confirm routing is enabled.Wrong answer — click to see why▾
Why this is wrong here
This option revisits a step already completed and verified, making it redundant. Candidates might think double-checking routing is safe, but the scenario explicitly states routing is working as expected.
✗Configure a default route pointing to the next-hop gateway.Wrong answer — click to see why▾
Why this is wrong here
Some candidates might believe inter-VLAN communication requires a default route, but directly connected routes already provide full reachability without static routing. This action is overly drastic and misdirected.
✗Verify the VLAN membership of the destination host on VLAN 20.Wrong answer — click to see why▾
Why this is wrong here
Candidates often jump to VLAN misconfigurations when inter-VLAN communication fails, even when routing is confirmed. The scenario already establishes the VLAN 20 host's location; the next logical layer to inspect is ARP resolution.
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
Access Control Model Comparison
| Model | Acronym | Who Controls Access? | Best For |
|---|---|---|---|
| Discretionary Access Control | DAC | Resource owner | Small teams, file shares |
| Mandatory Access Control | MAC | System / security labels | Classified govt / military |
| Role-Based Access Control | RBAC | Administrator (via roles) | Enterprise environments |
| Attribute-Based Access Control | ABAC | Policy engine (user + resource attributes) | Fine-grained, dynamic policies |
| Rule-Based Access Control | RuBAC | System rules / ACLs | Firewall rules, network ACLs |
Go deeper
Related to this question
Learn chapter
Configuring Switch Ports for Desktops, VoIP Phones, APs, IoT, and Virtualized Hosts
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.
Key term
VLAN
A VLAN (Virtual Local Area Network) is a logical grouping of network devices that behave as if they are on the same physical network segment, regardless of their actual physical location.
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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.