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ISC2 CC Practice Question: A network administrator is designing a DMZ to…
A network administrator is designing a DMZ to host a public-facing web server and a database server that should only be accessible from the web server. Which of the following firewall rule sets best achieves this design?
⚠ Common exam trap
ISC2 often tests the principle of least privilege by including options that allow overly broad access (like 'all traffic' from web to database) or reverse the direction of connections, so the trap here is assuming that any traffic between the web server and database is acceptable without specifying the exact protocol and port.
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
✓
Allow inbound HTTP/HTTPS to web server; allow web server to database on port 3306; deny all else
It implements the principle of least privilege for a DMZ: it allows inbound HTTP/HTTPS traffic (ports 80/443) to the public-facing web server, then permits only the web server to initiate outbound connections to the database server on port 3306 (MySQL/MariaDB default), and denies all other traffic. This ensures the database is not directly accessible from the internet, reducing the attack surface while still supporting the required application flow.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Allow inbound HTTP/HTTPS to web server; allow web server to database on port 3306; deny all else
Why this is correct
This permits necessary traffic and restricts database access to only the web server.
- ✗
Allow web server to initiate outbound connections to internet; allow database to initiate connections to web server; deny all else
Why it's wrong here
This does not allow inbound web traffic from the internet.
- ✗
Allow inbound HTTP/HTTPS to web server; allow all traffic from web server to database; deny all else
Why it's wrong here
Allowing all traffic from web server to database is too broad; only specific ports should be allowed.
- ✗
Allow inbound HTTP/HTTPS to web server; allow inbound SQL from internet to database; deny all else
Why it's wrong here
This exposes the database to the internet, which is insecure.
Go deeper
Related to this question
Learn chapter
Network Security Foundations
Key term
Access control
Access control is the security practice of determining who or what is allowed to view, use, or enter a resource, and under what conditions.
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.
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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.