The correct answer is configuring VLANs to separate departmental traffic and implementing firewall rules between internal zones. These are both examples of network segmentation controls because they divide a network into smaller, isolated segments to restrict traffic flow and contain potential threats. VLANs achieve logical separation at Layer 2, allowing different departments to share the same physical switch while remaining isolated from each other, while firewalls enforce segmentation at Layer 3 or above by applying access control lists between security zones like inside, outside, and DMZ. On the ISC2 Certified in Cybersecurity CC exam, this concept tests your understanding of defense-in-depth and lateral movement prevention—a common trap is confusing physical separation (like air gaps) with logical segmentation, but the exam focuses on practical controls like VLANs and firewalls. Remember the mnemonic: “VLANs slice, firewalls dice”—VLANs segment by group, firewalls segment by rule.
ISC2 CC Network Security Practice Question
This CC practice question tests your understanding of network security. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. 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 network security team is implementing a defense-in-depth strategy. Which TWO of the following controls are examples of network segmentation? (Choose two.)
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Implementing firewall rules between internal zones.
Option A is correct because implementing firewall rules between internal zones is a form of network segmentation. By creating distinct security zones (e.g., inside, outside, DMZ) and applying access control lists (ACLs) or stateful firewall policies between them, traffic is restricted to only what is explicitly permitted, thereby isolating network segments and limiting lateral movement.
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.
✓
Implementing firewall rules between internal zones.
Why this is correct
Firewalls enforce segmentation by controlling traffic between zones.
Related concept
Read the scenario before looking for a memorised answer.
✗
Deploying an intrusion detection system (IDS) on the core switch.
Why it's wrong here
IDS monitors traffic but does not segment the network.
✓
Configuring VLANs to separate departmental traffic.
Why this is correct
VLANs create separate broadcast domains, segmenting the network.
Related concept
Read the scenario before looking for a memorised answer.
✗
Placing public-facing servers in a DMZ.
Why it's wrong here
DMZ is a result of segmentation, not the control itself.
Common exam trap: answer the scenario, not the keyword
ISC2 often tests the distinction between segmentation (which actively isolates traffic) and other security controls like monitoring (IDS), placement (DMZ), or encryption (VPN), leading candidates to confuse architectural placement or tunneling with the actual act of segmenting the network.
Detailed technical explanation
How to think about this question
Network segmentation relies on Layer 2 (VLANs) or Layer 3 (subnets with ACLs/firewalls) boundaries to enforce traffic isolation. VLANs use 802.1Q tagging to separate broadcast domains on the same physical switch, while firewall rules between zones operate at Layers 3-4 (and sometimes Layer 7) to filter inter-zone traffic. In a real-world scenario, a PCI DSS environment requires segmentation of the cardholder data environment (CDE) from the rest of the network, often achieved by VLANs and firewall rules that block all traffic except necessary protocols.
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 security analyst at a medium-sized enterprise encounters this scenario during an investigation or architecture review. The correct answer reflects best practice for the specific threat or control described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Security exam questions test whether you can match controls to threats in context — not just recall definitions.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this CC question in full detail.
Network Security — This question tests Network Security — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Implementing firewall rules between internal zones. — Option A is correct because implementing firewall rules between internal zones is a form of network segmentation. By creating distinct security zones (e.g., inside, outside, DMZ) and applying access control lists (ACLs) or stateful firewall policies between them, traffic is restricted to only what is explicitly permitted, thereby isolating network segments and limiting lateral movement.
What should I do if I get this CC 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.
About these practice questions
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These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A helpdesk technician receives a report that a user in the finance department cannot access a shared folder on the server. The same server is accessible from other departments. What is the most likely cause?
easy
A.The server is down
✓ B.A firewall rule is blocking traffic from the finance VLAN to the server
C.The network cable is unplugged
D.The user's account is disabled
Why B: The scenario describes a user in the finance department unable to access a shared folder on a server that is reachable from other departments. This points to a segmentation or access control issue specific to the finance VLAN. A firewall rule blocking traffic from the finance VLAN to the server is the most likely cause because it would selectively prevent access for that subnet while allowing other VLANs to reach the server, matching the symptom of partial connectivity.
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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.
Question Discussion
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