Question 801 of 1,020
Network Configuration ConceptsmediumMultiple ChoiceObjective-mapped

How to Enable Inter-VLAN Routing for Cross-VLAN Access

This 220-1201 practice question tests your understanding of network configuration concepts. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.

A company has a network with multiple VLANs. A user in VLAN 10 cannot access a server in VLAN 20, but other users in VLAN 10 can access the server. The technician checks the switch configuration and finds that the port for the user is set to access mode for VLAN 10. What should be configured to allow this user to reach the server?

Quick Answer

The correct answer is to enable inter-VLAN routing on the router or Layer 3 switch. This is necessary because VLANs create separate broadcast domains, meaning devices in VLAN 10 and VLAN 20 cannot communicate directly at Layer 2; they require a Layer 3 device to forward traffic between them. Since the user’s access port is already correctly assigned to VLAN 10, the issue is not with port configuration but with the lack of a routing path between the VLANs. On the CompTIA A+ Core 1 220-1201 exam, this question tests your understanding of how inter-VLAN routing configuration enables cross-VLAN access, often appearing as a scenario where a single user is isolated while others in the same VLAN work fine—a common trap is to mistakenly change the access port or add a trunk. Remember the key principle: same VLAN, no router needed; different VLANs, a router or Layer 3 switch is mandatory. A helpful memory tip is “VLANs are walls; routing is the door.”

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

Enable inter-VLAN routing on the router or Layer 3 switch

The user in VLAN 10 cannot reach the server in VLAN 20 because they are in different subnets. Even though the switch port is correctly configured for VLAN 10, traffic between VLANs requires a Layer 3 device (router or Layer 3 switch) to perform inter-VLAN routing. Enabling this on the router or Layer 3 switch allows the user's packets to be forwarded from VLAN 10 to VLAN 20.

Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

  • Change the user's port to trunk mode

    Why it's wrong here

    Trunk mode is for carrying multiple VLANs between switches, not for connecting a single end device; it would not solve the routing issue.

  • Configure a static route on the user's computer

    Why it's wrong here

    Static routes on a client are rarely used and would not enable inter-VLAN routing; that requires network infrastructure configuration.

  • Enable inter-VLAN routing on the router or Layer 3 switch

    Why this is correct

    Inter-VLAN routing allows traffic to pass between different VLANs; without it, devices in separate VLANs cannot communicate.

    Related concept

    Read the scenario before looking for a memorised answer.

  • Assign the user's port to VLAN 20

    Why it's wrong here

    Moving the user to VLAN 20 would put them in the same VLAN as the server, but this is not a scalable solution and does not fix the underlying routing issue.

Common exam traps

Common exam trap: answer the scenario, not the keyword

A common misconception is that simply placing devices in the same VLAN or using trunk ports enables cross-VLAN communication, but in fact a Layer 3 routing process is required.

Detailed technical explanation

How to think about this question

Inter-VLAN routing can be implemented using a router-on-a-stick (with subinterfaces and 802.1Q trunking) or a Layer 3 switch with switched virtual interfaces (SVIs). The SVI acts as the default gateway for each VLAN, and the switch performs routing between VLANs in hardware using CEF (Cisco Express Forwarding). A common oversight is forgetting to enable IP routing on the Layer 3 switch with the 'ip routing' command, which is required for the SVIs to forward traffic.

KKey Concepts to Remember

  • Read the scenario before looking for a memorised answer.
  • Find the constraint that changes the correct option.
  • Eliminate answers that are true in general but not in this case.

TExam Day Tips

  • Watch for words such as best, first, most likely and least administrative effort.
  • Review why wrong options are wrong, not only why the correct option is correct.

Key takeaway

Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.

Real-world example

How this comes up in practice

A help-desk technician troubleshoots why a newly connected PC cannot reach shared printers on the same floor. The cable is good, the switch port is active, but the PC is in VLAN 20 and the printers are in VLAN 10. The uplink trunk only allows VLAN 10. A trunk being up does not mean every VLAN crosses it.

Visual reference

Switch VLAN 10 Sales (192.168.10.0/24) PC-A PC-B VLAN 20 HR (192.168.20.0/24) PC-C PC-D Router VLANs isolate traffic — inter-VLAN routing requires a Layer 3 device

What to study next

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FAQ

Questions learners often ask

What does this 220-1201 question test?

Network Configuration Concepts — This question tests Network Configuration Concepts — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: Enable inter-VLAN routing on the router or Layer 3 switch — The user in VLAN 10 cannot reach the server in VLAN 20 because they are in different subnets. Even though the switch port is correctly configured for VLAN 10, traffic between VLANs requires a Layer 3 device (router or Layer 3 switch) to perform inter-VLAN routing. Enabling this on the router or Layer 3 switch allows the user's packets to be forwarded from VLAN 10 to VLAN 20.

What should I do if I get this 220-1201 question wrong?

Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.

What is the key concept behind this question?

Read the scenario before looking for a memorised answer.

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Last reviewed: Jul 4, 2026

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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.