ANS-C01 Network Security, Compliance and Governance Practice Question
A company has an Amazon RDS for MySQL database in a private subnet. The database should only be accessible from a specific fleet of EC2 instances in the same VPC. Which combination of security controls should be used to meet this requirement?
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 security group for the RDS instance that allows inbound MySQL traffic from the security group of the EC2 instances.
A security group on the RDS instance that allows inbound MySQL traffic from the security group of the EC2 instances restricts access to only those instances that are members of that security group. Option A is incorrect because network ACLs are stateless and operate at the subnet level, requiring explicit inbound and outbound rules; they cannot reference security groups. Option B is incorrect because a VPN connection is used for connectivity to external networks, not for communication within the same VPC. Option D is incorrect because IAM database authentication controls user authentication to the database, not network-level access from EC2 instances.
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 network ACL on the private subnet that allows MySQL traffic from the EC2 instances' IP addresses.
Why it's wrong here
Network ACLs are stateless and require both inbound and outbound rules; they are less secure than security groups.
- ✗
Set up a VPN connection between the EC2 instances and the RDS instance.
Why it's wrong here
VPN is unnecessary for traffic within the same VPC.
- ✓
Use a security group for the RDS instance that allows inbound MySQL traffic from the security group of the EC2 instances.
Why this is correct
Security group rules can reference other security groups, providing instance-level access control.
- ✗
Enable IAM database authentication for the RDS instance and require EC2 instances to use IAM credentials.
Why it's wrong here
IAM authentication controls user access, not network-level access.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This ANS-C01 practice question is part of Courseiva's free Amazon Web Services 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 ANS-C01 exam.