- A
Use a single firewall to connect internet, DMZ, and internal network
Why wrong: A single firewall may not provide sufficient separation.
- B
Allow all traffic from the DMZ to the internal network for ease of management
Why wrong: This would expose internal network to risk.
- C
Use a separate VLAN for DMZ servers to isolate traffic
VLAN segmentation adds another layer of isolation.
- D
Place a firewall between the internet and the DMZ, and another between the DMZ and the internal network
Two firewalls provide defense in depth.
- E
Configure strict access control rules to allow only necessary services
Minimize exposure by permitting only required ports/protocols.
Question 512 of 1,000
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.
An organization is planning to deploy a DMZ to host web and email servers accessible from the internet. Which three security best practices should be implemented for the DMZ? (Choose three.)
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"best"Why it matters: Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
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
✓
Use a separate VLAN for DMZ servers to isolate traffic
Firewalls on both sides, strict access rules, and separate VLANs are best practices. Direct internal access and single firewall are not recommended.
Key principle: A trunk being up does not mean the VLAN is allowed across it. Always verify the allowed VLAN list and whether the VLAN exists on both switches.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Use a single firewall to connect internet, DMZ, and internal network
Why it's wrong here
A single firewall may not provide sufficient separation.
- ✗
Allow all traffic from the DMZ to the internal network for ease of management
Why it's wrong here
This would expose internal network to risk.
- ✓
Use a separate VLAN for DMZ servers to isolate traffic
- ✓
Place a firewall between the internet and the DMZ, and another between the DMZ and the internal network
Why this is correct
Two firewalls provide defense in depth.
Clue confirmation
The clue word "best" in the question point toward this answer.
Related concept
Access ports place end devices into a single VLAN.
- ✓
Configure strict access control rules to allow only necessary services
Why this is correct
Minimize exposure by permitting only required ports/protocols.
Clue confirmation
The clue word "best" in the question point toward this answer.
Related concept
Access ports place end devices into a single VLAN.
Common exam traps
Common exam trap: an active trunk can still block the VLAN you need
A trunk being up does not prove every VLAN is crossing it. Check allowed VLAN lists, native VLAN mismatch, VLAN existence and access-port assignment.
Detailed technical explanation
How to think about this question
VLAN questions usually combine access-port and trunking clues. The key is to identify whether the issue is local to one switchport, caused by the trunk, or caused by the VLAN not existing where it needs to exist.
KKey Concepts to Remember
- Access ports place end devices into a single VLAN.
- Trunk ports carry multiple VLANs between switches.
- Allowed VLAN lists decide which VLANs can cross a trunk.
- Native VLAN mismatch can create confusing symptoms.
TExam Day Tips
- Use show vlan brief to verify access VLANs.
- Use show interfaces trunk to verify trunk state and allowed VLANs.
- Do not treat every same-VLAN issue as a routing problem.
Key takeaway
A trunk being up does not mean the VLAN is allowed across it. Always verify the allowed VLAN list and whether the VLAN exists on both switches.
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. A trunk being up does not mean the VLAN is allowed across it. Always verify the allowed VLAN list and whether the VLAN exists on both switches. Security exam questions test whether you can match controls to threats in context — not just recall definitions.
Visual reference
What to study next
Got this wrong? Here's your next step.
Review VLAN allowed lists, native VLAN mismatch detection, and how to verify VLAN membership with show vlan brief and show interfaces trunk. Then practise related CC questions on switching, trunking, and access-port configuration.
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FAQ
Questions learners often ask
What does this CC question test?
Network Security — This question tests Network Security — Access ports place end devices into a single VLAN..
What is the correct answer to this question?
The correct answer is: Use a separate VLAN for DMZ servers to isolate traffic — Firewalls on both sides, strict access rules, and separate VLANs are best practices. Direct internal access and single firewall are not recommended.
What should I do if I get this CC question wrong?
Review VLAN allowed lists, native VLAN mismatch detection, and how to verify VLAN membership with show vlan brief and show interfaces trunk. Then practise related CC questions on switching, trunking, and access-port configuration.
Are there clue words in this question I should notice?
Yes — watch for: "best". Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
What is the key concept behind this question?
Access ports place end devices into a single VLAN.
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Last reviewed: Jul 4, 2026
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.
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