hardMultiple ChoiceObjective-mapped
220-1201 Practice Question: A company's network uses a managed switch with…
A company's network uses a managed switch with VLANs. Users in VLAN 10 can ping the default gateway but cannot communicate with users in VLAN 20. The switch is connected to a router that handles inter-VLAN routing. What is the most likely misconfiguration?
⚠ Common exam trap
The 220-1201 exam often tests the misconception that inter-VLAN routing can work with an access port if the router's interface is configured with an IP address, but the trap is that an access port strips VLAN tags, so the router cannot differentiate between VLANs, breaking communication.
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 connecting to the router is configured as an access port instead of a trunk.
The most likely misconfiguration is that the switch port connecting to the router is configured as an access port instead of a trunk. For inter-VLAN routing to work, the router must receive traffic from multiple VLANs on the same physical interface. A trunk port (using 802.1Q tagging) allows frames from VLAN 10 and VLAN 20 to be forwarded to the router, which then routes between them. An access port can only carry traffic for a single VLAN, so frames from VLAN 20 would be dropped or misdirected, preventing communication.
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 router's firewall is blocking traffic between VLANs.
Why it's wrong here
If the router's firewall were blocking inter-VLAN traffic, it would typically be a deliberate security policy rather than an accidental misconfiguration preventing basic communication. Since users can ping their own default gateway, the router is reachable, suggesting the issue isn't a complete block of all router-bound traffic. A firewall would specifically deny forwarding packets between different subnets/VLANs, but the core problem here seems to be the router not receiving traffic from all VLANs to begin with for routing.
- ✓
The switch port connecting to the router is configured as an access port instead of a trunk.
Why this is correct
An access port is designed to carry traffic for a single, untagged VLAN, typically connecting to an end device like a PC. For a router to perform inter-VLAN routing, it must receive traffic from multiple VLANs over a single physical link. This requires the switch port connected to the router to be configured as a trunk port, which tags Ethernet frames with their respective VLAN IDs (e.g., 802.1Q) allowing the router to differentiate and route traffic between them. If it's an access port, the router only sees traffic for that single configured VLAN, preventing communication with other VLANs.
- ✗
The default gateway for VLAN 20 is misconfigured.
Why it's wrong here
The problem statement indicates that users in VLAN 20 can ping their default gateway. This directly refutes a misconfigured default gateway, as they would be unable to reach it if the IP address or subnet mask was incorrect. A misconfigured gateway would prevent any outbound communication from VLAN 20 to any other network, including other VLANs or the internet, because packets wouldn't know where to go to leave their local subnet.
- ✗
The switch has Spanning Tree Protocol enabled, blocking the link.
Why it's wrong here
Spanning Tree Protocol (STP) is designed to prevent network loops by blocking redundant paths between switches. In a typical inter-VLAN routing setup, there is usually only a single physical link connecting the switch to the router. STP would not block this essential, non-redundant link, as doing so would isolate the entire network segment from the router and other VLANs. If STP were blocking this link, users in all VLANs would be unable to reach their default gateways.
Visual reference
Go deeper
Related to this question
Learn chapter
Network Configuration: IP, DNS, DHCP
Key term
Switch Virtual Interface
A logical interface on a network switch that allows it to be managed and communicate with other devices using IP addresses.
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.
About these practice questions
This 220-1201 question is part of Courseiva's 972-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam dumps. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 220-1201 practice question is part of Courseiva's free CompTIA 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 220-1201 exam.