mediumMultiple ChoiceObjective-mapped
ISC2 CC Practice Question: Is designing a network for a small business that…
A security engineer is designing a network for a small business that needs to segregate guest Wi-Fi from the internal corporate network. The guest network should have internet access only, with no access to internal resources. Which of the following is the BEST design approach?
⚠ Common exam trap
ISC2 often tests the misconception that simply using different IP subnets on the same VLAN provides security, when in fact true isolation requires separate VLANs or firewall rules to prevent Layer 2 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
✓
Place the guest Wi-Fi on a separate VLAN with a firewall rule blocking traffic to internal subnets.
The best approach because placing the guest Wi-Fi on a separate VLAN and applying a firewall rule to block traffic to internal subnets provides both logical segmentation and access control. This ensures that guest traffic is isolated at Layer 2 (VLAN) and Layer 3/4 (firewall), preventing any unauthorized access to the corporate network while still allowing internet connectivity through a default route.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Implement MAC address filtering on the access point to allow only known devices.
Why it's wrong here
MAC filtering does not restrict network-level access; all allowed devices would be on the same network as internal resources.
- ✗
Connect the guest Wi-Fi to the internet through a separate router that does not have routes to the internal network.
Why it's wrong here
This works but is less efficient and scalable than VLAN segmentation with a single router/firewall.
- ✗
Use a single VLAN with a DHCP server that assigns different IP ranges to guests and employees.
Why it's wrong here
Devices on the same VLAN can communicate directly regardless of IP range, so internal resources would be reachable.
- ✓
Place the guest Wi-Fi on a separate VLAN with a firewall rule blocking traffic to internal subnets.
Why this is correct
This creates logical isolation and allows granular control over traffic between VLANs.
Visual reference
Go deeper
Related to this question
Learn chapter
Introduction to Security Principles
Key term
Firewall rule
A firewall rule is a set of conditions that tells a firewall which network traffic to allow or block based on attributes like source, destination, port, and protocol.
Key term
Least privilege
Least privilege is a security principle that means giving users, systems, or programs only the minimum permissions they need to do their job and nothing more.
About these practice questions
Courseiva writes every CC question from scratch — 976 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or 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 CC practice question is part of Courseiva's free ISC2 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 CC exam.