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Deployment and MigrationeasyMultiple ChoiceObjective-mapped

DBS-C01 Deployment and Migration Practice Question

Network Topology
$ aws rds describe-db-instancesdb-instance-identifier mydbquery 'DBInstances[0].Endpoint'Refer to the exhibit."Address": "mydb.abc123xyz.us-east-1.rds.amazonaws.com","Port": 3306,"HostedZoneId": "Z2R2ITUGPM61AM"

Refer to the exhibit. A company is migrating from an on-premises MySQL database to Amazon RDS for MySQL. The DBA wants to connect to the RDS instance using the endpoint shown. What additional step is required to allow the DBA's client to connect?

⚠ Common exam trap

The DBS-C01 exam often tests the misconception that making an RDS instance publicly accessible alone is sufficient for connectivity, but the security group rule is the actual gatekeeper; public accessibility only assigns a public IP, while the security group still blocks traffic without an explicit inbound rule.

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

Modify the security group to allow inbound traffic on port 3306 from the client IP

Amazon RDS security groups act as a virtual firewall controlling inbound and outbound traffic. By default, no inbound traffic is allowed on port 3306 (MySQL). To permit the DBA's client to connect, you must modify the security group associated with the RDS instance to add an inbound rule that allows TCP traffic on port 3306 from the client's IP address (or a range that includes it). Without this rule, the connection is blocked at the network level regardless of other configurations.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

  • Modify the security group to allow inbound traffic on port 3306 from the client IP

    Why this is correct

    Security group rules control inbound traffic; port 3306 must be open.

  • Create a Route 53 record for the endpoint

    Why it's wrong here

    The endpoint DNS is already provided; no additional Route 53 record is needed.

  • Create a MySQL user that matches the client's IP

    Why it's wrong here

    A MySQL user is needed, but that is part of setup, not the connection issue.

  • Change the RDS instance to be publicly accessible

    Why it's wrong here

    The instance may already be public; the endpoint is shown, but security group still needs to allow access.

Visual reference

Client Server SYN (seq=100) SYN-ACK (seq=200, ack=101) ACK (ack=201) Connection established — data transfer begins

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JA

Written by Johnson Ajibi, MSc IT Security

Senior Network & Security Engineer · founder of Courseiva

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.