CCNA Network Infrastructure and Connectivity Practice Question
A technician is troubleshooting a connectivity issue where a workstation connected to a Cisco switch port cannot ping other hosts that are in the same VLAN 10 segment. The technician runs the show mac address-table command and notices that the workstation's MAC address is listed on VLAN 1, not VLAN 10. What is the most likely cause?
⚠ Common exam trap
Cisco often tests the default VLAN behavior (VLAN 1) and the fact that an access port without an explicit VLAN assignment remains in VLAN 1, leading candidates to overlook the missing `switchport access vlan` command and instead blame trunking, STP, or MAC table aging.
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 switch port is not configured with the switchport access vlan 10 command.
The workstation's MAC address appears in VLAN 1 instead of VLAN 10 because the switch port is operating in the default VLAN (VLAN 1). The most likely cause is that the port has not been explicitly assigned to VLAN 10 using the `switchport access vlan 10` command. Without this command, the port remains in its default access VLAN (VLAN 1), so all frames from the workstation are associated with VLAN 1, preventing communication with hosts in VLAN 10.
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 switch port is not configured with the switchport access vlan 10 command.
Why this is correct
When an access port's VLAN is not explicitly set, the port defaults to VLAN 1. The workstation's MAC is learned on VLAN 1, causing connectivity failure with VLAN 10 hosts. Adding the switchport access vlan 10 command resolves the issue.
- ✗
The switch port is configured as a trunk with native VLAN 1.
Why it's wrong here
While a trunk with native VLAN 1 would place untagged frames into VLAN 1, there is no evidence that the port is a trunk. The typical oversight for a host port is forgetting to set the access VLAN, not configuring a trunk. The problem explicitly notes that the access VLAN is not configured.
- ✗
The MAC address table contains a stale entry that must be cleared.
Why it's wrong here
Clearing the MAC address table would not change the VLAN assignment. A new entry would still be learned on VLAN 1 because the port's operational VLAN is 1. The stale entry is a symptom, not the root cause of the VLAN mismatch.
- ✗
Spanning Tree Protocol has placed the port in a blocking state.
Why it's wrong here
STP blocking prevents frame forwarding but does not stop MAC address learning. The switch would still learn the workstation's MAC on whatever VLAN the port is in. The MAC showing on VLAN 1 indicates a VLAN configuration issue, not an STP state.
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 switch port is not configured with the switchport access vlan 10 command.Correct answer▾
Why this is correct
When an access port's VLAN is not explicitly set, the port defaults to VLAN 1. The workstation's MAC is learned on VLAN 1, causing connectivity failure with VLAN 10 hosts. Adding the switchport access vlan 10 command resolves the issue.
✗The switch port is configured as a trunk with native VLAN 1.Wrong answer — click to see why▾
Why this is wrong here
Candidates often assume any VLAN mismatch with VLAN 1 indicates a trunk misconfiguration, but a missing access VLAN is the more common and direct cause.
✗The MAC address table contains a stale entry that must be cleared.Wrong answer — click to see why▾
Why this is wrong here
Candidates might think that an outdated MAC record is causing the VLAN display, but the dynamic learning process reflects the actual port VLAN.
✗Spanning Tree Protocol has placed the port in a blocking state.Wrong answer — click to see why▾
Why this is wrong here
Tempting because a blocked port can disrupt connectivity, but the MAC address table entry would still appear on the correct VLAN, not default to VLAN 1.
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
IPv4 Addressing and Address Classes
Key term
Switchport
A switchport is a physical or virtual interface on a network switch that connects devices like computers, printers, or other switches to a local area network.
Key term
MAC address
A MAC address is a unique hardware identifier assigned to a network interface card that allows devices to communicate on a local network.
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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.