220-1101 Networking Practice Question
A technician is setting up a small office network with a single internet connection from a cable modem. The office has two departments: Accounting and Sales. The technician needs to ensure that devices in Accounting cannot communicate with devices in Sales, but both departments must be able to access the internet. Which feature should the technician configure on the managed switch to meet this requirement?
⚠ Common exam trap
The 220-1101 exam often tests VLANs as the solution for network segmentation, and the trap here is that candidates confuse VLANs with subnetting or think that simply using different IP subnets alone (without VLANs) will prevent communication, but switches forward frames based on MAC addresses, not IP addresses, so VLANs are required to enforce isolation at Layer 2.
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
✓
Configure VLANs on the managed switch
VLANs (Virtual Local Area Networks) logically segment a switch into multiple isolated broadcast domains. By placing Accounting devices in one VLAN and Sales devices in another, the switch prevents Layer 2 communication between them, while both VLANs can still access the internet through a router configured with inter-VLAN routing or a separate uplink.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Configure VLANs on the managed switch
Why this is correct
Configuring VLANs on the managed switch creates multiple isolated Layer 2 broadcast domains within a single physical switch. Each department can be assigned its own VLAN ID, and traffic between VLANs is blocked by default at Layer 2, requiring a Layer 3 router or switch to forward it. This allows you to apply access control policies between groups while the router provides a shared default route to the internet for all VLANs. VLANs are the correct mechanism for separating internal traffic at the switch level.
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Enable DHCP on the router
Why it's wrong here
Enabling DHCP on the router simplifies IP address management by automatically assigning addresses, but it has no effect on traffic isolation. All devices that receive addresses from the router will exist on the same subnet unless VLANs or separate subnets are configured, and they can freely communicate with each other at Layer 2. DHCP is a control-plane service, not a data-plane segmentation tool, so it cannot prevent inter-device communication.
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Set up port forwarding on the router
Why it's wrong here
Port forwarding on the router creates static NAT rules that redirect specific inbound ports from the router's public IP to an internal host's private IP. This is used to expose internal services to the internet, such as a web server or security camera, and does not influence how internal devices communicate with each other. It actually increases external reachability rather than isolating internal traffic, and it has no bearing on Layer 2 broadcast domains.
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Configure NAT on the router
Why it's wrong here
NAT (Network Address Translation) maps private IP addresses to a public IP address for outbound internet connectivity, and keeps the internal network hidden from external hosts. However, NAT is an edge function performed on the router's WAN interface and does not separate devices within the LAN; internal hosts still see each other's private addresses and can communicate directly if they share the same subnet. It is not a substitute for VLAN-based segmentation.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 220-1101 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 220-1101 exam.