- A
Web in public subnet, app and database in private subnets with appropriate routing
This separates internet-facing from internal tiers, reducing risk.
- B
Web and app in public subnets, database in private subnet
Why wrong: Application should not be directly exposed to the internet.
- C
All tiers in private subnets with a VPN
Why wrong: Web tier needs internet access; VPN only for admin access.
- D
All tiers in the same public subnet with security groups
Why wrong: This exposes all tiers to the internet, increasing attack surface.
Question 445 of 997
CV0-004 Cloud Architecture and Design Practice Question
This CV0-004 practice question tests your understanding of cloud architecture and design. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. 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 cloud architect is designing a VPC with three tiers: web, application, and database. Which subnet design provides the best security posture?
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
✓
Web in public subnet, app and database in private subnets with appropriate routing
Option A is correct because it follows the principle of least privilege and network segmentation. Placing the web tier in a public subnet allows it to receive internet traffic, while the application and database tiers reside in private subnets with no direct internet access. This design ensures that only the web tier is exposed, and the database is isolated, accessible only via the application tier through controlled routing, significantly reducing the attack surface.
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.
- ✓
Web in public subnet, app and database in private subnets with appropriate routing
Why this is correct
This separates internet-facing from internal tiers, reducing risk.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Web and app in public subnets, database in private subnet
Why it's wrong here
Application should not be directly exposed to the internet.
- ✗
All tiers in private subnets with a VPN
Why it's wrong here
Web tier needs internet access; VPN only for admin access.
- ✗
All tiers in the same public subnet with security groups
Why it's wrong here
This exposes all tiers to the internet, increasing attack surface.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the misconception that security groups alone are sufficient for network segmentation, leading candidates to choose Option D, but security groups are stateful firewalls at the instance level and do not replace the need for subnet-level isolation and controlled routing paths.
Detailed technical explanation
How to think about this question
In AWS, a public subnet has a route to an Internet Gateway (IGW) via its route table, while private subnets route through a NAT Gateway or Virtual Private Gateway. The three-tier architecture leverages network ACLs (stateless) and security groups (stateful) to enforce traffic flow: web-to-app on specific ports (e.g., HTTP/HTTPS), and app-to-database on database ports (e.g., MySQL 3306). A real-world scenario involves a web application where the database contains sensitive customer data; isolating the database in a private subnet prevents direct exposure even if the web server is compromised, as the attacker would need to pivot through the application tier, which can be further hardened.
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 junior network technician can log in to a core router but cannot reach the enable prompt or configuration mode. The AAA server is authenticating the login — but the authorisation policy only grants privilege level 1, not 15. Authentication (who you are) is working; authorisation (what you can do) is not.
Visual reference
What to study next
Got this wrong? Here's your next step.
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FAQ
Questions learners often ask
What does this CV0-004 question test?
Cloud Architecture and Design — This question tests Cloud Architecture and Design — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Web in public subnet, app and database in private subnets with appropriate routing — Option A is correct because it follows the principle of least privilege and network segmentation. Placing the web tier in a public subnet allows it to receive internet traffic, while the application and database tiers reside in private subnets with no direct internet access. This design ensures that only the web tier is exposed, and the database is isolated, accessible only via the application tier through controlled routing, significantly reducing the attack surface.
What should I do if I get this CV0-004 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.
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Last reviewed: Jul 4, 2026
This CV0-004 practice question is part of Courseiva's free CompTIA 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 CV0-004 exam.
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