Quick Answer
The answer is to enable SSL/TLS and require client connections to use SSL. This configuration ensures encryption in transit for Amazon RDS for PostgreSQL because SSL/TLS encrypts the data as it travels between the client and the database server, preventing interception or tampering over the network. Simply enabling encryption at rest or using AWS KMS only protects stored data, not data in motion, while a default VPC provides network isolation but no encryption. On the AWS Certified Database Specialty DBS-C01 exam, this question tests your ability to distinguish between encryption at rest and in transit, a common trap where candidates confuse KMS or VPC security groups with transport-layer security. Remember the mnemonic “SSL for the street, KMS for the seat”—SSL protects data on the network path, while KMS protects data sitting on disk.
This DBS-C01 practice question tests your understanding of deployment and migration. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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 company is deploying a new multi-AZ Amazon RDS for PostgreSQL database. The security team requires that all traffic to the database be encrypted in transit. Which configuration ensures this?
Use a customer master key (CMK) for RDS
Why wrong: CMK is for encryption at rest, not in transit.
Enable SSL/TLS and require client connections to use SSL
SSL/TLS encrypts data in transit.
Place the RDS instance in a public subnet
Why wrong: Public subnet does not enforce encryption.
Enable encryption at rest using AWS KMS
Why wrong: Encryption at rest does not encrypt data in transit.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Enable SSL/TLS and require client connections to use SSL
Enabling SSL/TLS and enforcing that client connections use SSL ensures encryption in transit. Option A (encryption at rest) does not cover transit. Option B (default VPC) does not enforce encryption. Option D (KMS) is for encryption at rest.
Key principle: Count usable hosts — not total addresses — and remember that the network and broadcast addresses are not available to hosts in standard IPv4 subnets.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
Use a customer master key (CMK) for RDS
Why it's wrong here
CMK is for encryption at rest, not in transit.
Enable SSL/TLS and require client connections to use SSL
Place the RDS instance in a public subnet
Why it's wrong here
Public subnet does not enforce encryption.
Enable encryption at rest using AWS KMS
Why it's wrong here
Encryption at rest does not encrypt data in transit.
Common exam traps
Subnetting questions often tempt you into counting all addresses. In normal IPv4 subnets, the network and broadcast addresses are not usable host addresses.
Detailed technical explanation
Subnetting questions test whether you can identify the network, broadcast address, usable range, mask and correct subnet. Slow down enough to calculate the block size correctly.
Key takeaway
Count usable hosts — not total addresses — and remember that the network and broadcast addresses are not available to hosts in standard IPv4 subnets.
Real-world example
A healthcare organisation deploys an application with a public-facing web tier and a private database tier. The database subnet has no public IP and only accepts connections from the web tier's security group. Questions like this test whether you can design cloud network isolation using VNets/VPCs, subnets, and security group rules.
What to study next
Review block sizes, usable host formulas (2^n − 2), and how to find network and broadcast addresses for /24 through /30. Then practise related DBS-C01 subnetting questions on CIDR, address ranges, and subnet selection.
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FAQ
Deployment and Migration — This question tests Deployment and Migration — CIDR notation defines the prefix length..
The correct answer is: Enable SSL/TLS and require client connections to use SSL — Enabling SSL/TLS and enforcing that client connections use SSL ensures encryption in transit. Option A (encryption at rest) does not cover transit. Option B (default VPC) does not enforce encryption. Option D (KMS) is for encryption at rest.
Review block sizes, usable host formulas (2^n − 2), and how to find network and broadcast addresses for /24 through /30. Then practise related DBS-C01 subnetting questions on CIDR, address ranges, and subnet selection.
CIDR notation defines the prefix length.
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Last reviewed: Jun 20, 2026
This DBS-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 DBS-C01 exam.
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