- A
Place the DMZ on the internal network side with a strong host-based firewall on each server
Why wrong: This defeats the purpose of a DMZ; the DMZ should be separate from the internal network to limit exposure.
- B
Place a single firewall between the internet and the DMZ, and allow traffic from DMZ to internal network
Why wrong: This would not protect the internal network if a DMZ server is compromised, as the firewall would permit outbound traffic from DMZ to internal.
- C
Use a stateful firewall that only allows return traffic from internal to DMZ
Why wrong: This configuration would not permit internal users to initiate connections to DMZ servers, which is often required, and still may allow compromised DMZ servers to initiate connections back to internal.
- D
Implement a screened subnet with two firewalls: one between internet and DMZ, and one between DMZ and internal network
This is the classic DMZ architecture that provides defense in depth; internal traffic must pass through the second firewall, preventing direct access from DMZ.
CISSP Communication and Network Security Practice Question
This CISSP practice question tests your understanding of communication and network security. 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.
An organization is implementing network segmentation to enhance security. They create a DMZ to host public-facing servers and want to ensure that if a server is compromised, the attacker cannot pivot to the internal network. Which firewall placement best achieves this?
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
Implement a screened subnet with two firewalls: one between internet and DMZ, and one between DMZ and internal network
Option D is correct because a screened subnet architecture uses two firewalls to create a DMZ that is logically isolated from both the internet and the internal network. The first firewall (internet-facing) controls inbound traffic to the DMZ, while the second firewall (internal-facing) strictly controls outbound traffic from the DMZ to the internal network, typically allowing only specific return traffic. This prevents an attacker who compromises a DMZ server from directly initiating connections to internal hosts, as the internal firewall would block such traffic unless explicitly permitted.
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.
- ✗
Place the DMZ on the internal network side with a strong host-based firewall on each server
Why it's wrong here
This defeats the purpose of a DMZ; the DMZ should be separate from the internal network to limit exposure.
- ✗
Place a single firewall between the internet and the DMZ, and allow traffic from DMZ to internal network
Why it's wrong here
This would not protect the internal network if a DMZ server is compromised, as the firewall would permit outbound traffic from DMZ to internal.
- ✗
Use a stateful firewall that only allows return traffic from internal to DMZ
Why it's wrong here
This configuration would not permit internal users to initiate connections to DMZ servers, which is often required, and still may allow compromised DMZ servers to initiate connections back to internal.
- ✓
Implement a screened subnet with two firewalls: one between internet and DMZ, and one between DMZ and internal network
Why this is correct
This is the classic DMZ architecture that provides defense in depth; internal traffic must pass through the second firewall, preventing direct access from DMZ.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often assume a single firewall with a DMZ interface (three-legged firewall) provides sufficient isolation, but without a second firewall or strict egress filtering, the DMZ can still be used as a pivot point to the internal network.
Detailed technical explanation
How to think about this question
In a screened subnet, the two firewalls typically implement different rule sets: the external firewall uses NAT and ACLs to permit only specific services (e.g., HTTP/HTTPS on TCP 80/443) to the DMZ, while the internal firewall uses strict egress filtering to allow only established connections or specific protocols (e.g., SMTP to internal mail servers) from the DMZ. This architecture is often deployed with a pair of firewalls in parallel or series, and can be further hardened by using a bastion host in the DMZ that proxies all internal access. In real-world scenarios, misconfiguration of the internal firewall's default deny rule is a common failure point, as administrators may inadvertently allow all traffic from the DMZ to internal networks.
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.
Visual reference
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
- →
Communication and Network Security — study guide chapter
Learn the concepts, then practise the questions
- →
Communication and Network Security practice questions
Targeted practice on this topic area only
- →
All CISSP questions
1,000 questions across all exam domains
- →
Certified Information Systems Security Professional CISSP study guide
Full concept coverage aligned to exam objectives
- →
CISSP practice test guide
How to use practice tests most effectively before exam day
Related practice questions
Related CISSP practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Security and Risk Management practice questions
Practise CISSP questions linked to Security and Risk Management.
Asset Security practice questions
Practise CISSP questions linked to Asset Security.
Security Operations practice questions
Practise CISSP questions linked to Security Operations.
Security Architecture and Engineering practice questions
Practise CISSP questions linked to Security Architecture and Engineering.
Communication and Network Security practice questions
Practise CISSP questions linked to Communication and Network Security.
Security Assessment and Testing practice questions
Practise CISSP questions linked to Security Assessment and Testing.
Software Development Security practice questions
Practise CISSP questions linked to Software Development Security.
Identity and Access Management practice questions
Practise CISSP questions linked to Identity and Access Management.
CISSP fundamentals practice questions
Practise CISSP questions linked to CISSP fundamentals.
CISSP scenario practice questions
Practise CISSP questions linked to CISSP scenario.
CISSP troubleshooting practice questions
Practise CISSP questions linked to CISSP troubleshooting.
Practice this exam
Start a free CISSP practice session
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
FAQ
Questions learners often ask
What does this CISSP question test?
Communication and Network Security — This question tests Communication and Network Security — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Implement a screened subnet with two firewalls: one between internet and DMZ, and one between DMZ and internal network — Option D is correct because a screened subnet architecture uses two firewalls to create a DMZ that is logically isolated from both the internet and the internal network. The first firewall (internet-facing) controls inbound traffic to the DMZ, while the second firewall (internal-facing) strictly controls outbound traffic from the DMZ to the internal network, typically allowing only specific return traffic. This prevents an attacker who compromises a DMZ server from directly initiating connections to internal hosts, as the internal firewall would block such traffic unless explicitly permitted.
What should I do if I get this CISSP 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
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Last reviewed: Jul 4, 2026
This CISSP 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 CISSP exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.