easyMultiple SelectObjective-mapped
CV0-004 Practice Question: A cloud administrator is configuring a new…
A cloud administrator is configuring a new virtual private cloud (VPC) with a public subnet for a web application. The administrator must ensure that the web application can receive HTTPS traffic from the internet but cannot be directly accessed via SSH. Which TWO security controls should the administrator implement? (Choose two.)
⚠ Common exam trap
CompTIA often tests the distinction between stateless (NACL) and stateful (security group) firewalls, and the trap here is that candidates may think a security group alone is sufficient to deny SSH, forgetting that a permissive NACL could allow SSH traffic to reach the subnet, or they may incorrectly assume a WAF can block SSH at the network layer.
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
✓
Configure a network ACL on the subnet to allow inbound TCP ports 80 and 443 from 0.0.0.0/0 and deny inbound TCP port 22.
A network ACL (NACL) is a stateless firewall that operates at the subnet level, allowing you to explicitly deny inbound TCP port 22 (SSH) while allowing TCP ports 80 and 443 (HTTP/HTTPS) from 0.0.0.0/0. Option D is correct because a security group (SG) is a stateful firewall at the instance level; by default, SGs deny all inbound traffic, so you must explicitly allow TCP port 443 from 0.0.0.0/0, and since SSH (port 22) is not allowed, it is implicitly denied. Together, these provide defense-in-depth: the NACL blocks SSH at the subnet boundary, and the SG ensures only HTTPS is permitted to the web server.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Attach an internet gateway (IGW) to the VPC and enable auto-assign public IP on the subnet.
Why it's wrong here
An IGW is needed for internet access but does not filter traffic.
- ✓
Configure a network ACL on the subnet to allow inbound TCP ports 80 and 443 from 0.0.0.0/0 and deny inbound TCP port 22.
Why this is correct
Network ACLs are stateless and provide subnet-level filtering; allowing HTTP/HTTPS and denying SSH adds defense.
- ✗
Place the web server in a private subnet and use a NAT gateway for outbound traffic.
Why it's wrong here
A private subnet cannot receive inbound internet traffic without additional components like a load balancer.
- ✓
Configure a security group that allows inbound TCP port 443 from 0.0.0.0/0 and denies inbound TCP port 22.
Why this is correct
Security groups are stateful and can allow/deny traffic. Allowing HTTPS and implicitly denying SSH meets the requirement.
- ✗
Deploy a web application firewall (WAF) in front of the web server.
Why it's wrong here
A WAF protects against web exploits, not port-based access control.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.