DBS-C01 Deployment and Migration Practice Question
A company is migrating a 100 GB Oracle database to Amazon RDS for Oracle. They want to use AWS DMS. The source database is in a different AWS account. What is required to allow DMS to connect to the source?
⚠ Common exam trap
Many candidates confuse IAM roles (which handle authorization for AWS services) with network connectivity requirements, assuming a role can grant DMS access to a database in another account, when in fact DMS needs direct network layer access via VPC peering or VPN.
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
✓
Establish VPC peering or VPN between the source and target VPCs, and configure security group rules.
AWS DMS requires network connectivity between the replication instance and the source database. Since the source is in a different AWS account, VPC peering or a VPN connection must be established to route traffic between the VPCs. Additionally, security group rules in both VPCs must allow inbound/outbound traffic on the Oracle listener port (default 1521) from the DMS replication instance's IP or security group.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Establish VPC peering or VPN between the source and target VPCs, and configure security group rules.
Why this is correct
DMS requires network connectivity between the replication instance and the source database.
- ✗
Assign an IAM role to the source database to allow DMS access.
Why it's wrong here
IAM roles are for AWS service permissions, not for database authentication.
- ✗
Configure an S3 VPC gateway endpoint for the source VPC.
Why it's wrong here
S3 endpoints are for S3 access, not for database connectivity.
- ✗
Create a VPC endpoint for DMS in the source account.
Why it's wrong here
VPC endpoints are for accessing AWS services, not for DMS connectivity to a database.
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Written by Johnson Ajibi, MSc IT Security
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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.