The correct answer is to use an S3 VPC Gateway endpoint combined with a bucket policy that includes the aws:SourceVpc condition key. This works because the Gateway endpoint routes all S3 traffic through the AWS private network, never leaving the AWS backbone, while the bucket policy’s aws:SourceVpc condition explicitly restricts access to traffic originating from your specific VPC ID, blocking any public internet or cross-VPC requests. On the AWS Certified Data Engineer Associate DEA-C01 exam, this scenario tests your understanding of how to enforce network-level isolation for S3 without exposing data to the internet—a common trap is confusing Interface endpoints (which still use public IPs) with Gateway endpoints, or mistakenly using aws:SourceIp, which only checks IP addresses and cannot enforce VPC boundaries. Remember the key distinction: Gateway endpoints keep traffic inside AWS, Interface endpoints do not. A helpful mnemonic is “Gateway goes private, Interface invites the internet.”
DEA-C01 Data Security and Governance Practice Question
This DEA-C01 practice question tests your understanding of data security and governance. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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 stores sensitive data in S3 and uses VPC endpoints to access the bucket. They need to ensure that only traffic from their VPC can access the data, and that the traffic cannot leave the AWS network. Which combination of bucket policy and endpoint policy should they use?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Use an S3 VPC Gateway endpoint and add a bucket policy with aws:SourceVpc condition
Option A is correct because using an S3 VPC Gateway endpoint and a bucket policy with aws:SourceVpc condition restricts traffic to the VPC and keeps it within AWS network. Option B is wrong because Interface endpoints still use public internet. Option C is wrong because bucket policies alone cannot restrict to VPC. Option D is wrong because aws:SourceIp does not restrict to VPC.
Key principle: NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
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 only a bucket policy with aws:SourceIp condition
Why it's wrong here
SourceIp does not restrict to VPC.
✓
Use an S3 VPC Gateway endpoint and add a bucket policy with aws:SourceVpc condition
Why this is correct
Gateway endpoints keep traffic within AWS network and the condition restricts to the VPC.
Related concept
Static NAT maps one inside address to one outside address.
✗
Use an S3 VPC Interface endpoint and add a bucket policy with aws:SourceVpce condition
Why it's wrong here
Interface endpoints use public internet for some traffic.
✗
Use an S3 VPC Gateway endpoint with no bucket policy
Why it's wrong here
Without bucket policy, any VPC can access.
Common exam traps
Common exam trap: NAT rules depend on direction and matching traffic
NAT is not only about the public address. The inside/outside interface roles and the ACL or rule that matches traffic are just as important.
Detailed technical explanation
How to think about this question
NAT questions usually test address translation, overload/PAT behaviour, static mappings and whether the right traffic is being translated. Read the interface direction and address terms carefully.
KKey Concepts to Remember
Static NAT maps one inside address to one outside address.
PAT allows many inside hosts to share one public address using ports.
Inside local and inside global describe the private and translated addresses.
NAT ACLs identify traffic for translation, not always security filtering.
TExam Day Tips
→Identify inside and outside interfaces first.
→Check whether the scenario needs static NAT, dynamic NAT or PAT.
→Do not confuse NAT matching ACLs with normal packet-filtering intent.
Key takeaway
NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
Real-world example
How this comes up in practice
A media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.
What to study next
Got this wrong? Here's your next step.
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related DEA-C01 NAT questions on configuration and troubleshooting.
Data Security and Governance — This question tests Data Security and Governance — Static NAT maps one inside address to one outside address..
What is the correct answer to this question?
The correct answer is: Use an S3 VPC Gateway endpoint and add a bucket policy with aws:SourceVpc condition — Option A is correct because using an S3 VPC Gateway endpoint and a bucket policy with aws:SourceVpc condition restricts traffic to the VPC and keeps it within AWS network. Option B is wrong because Interface endpoints still use public internet. Option C is wrong because bucket policies alone cannot restrict to VPC. Option D is wrong because aws:SourceIp does not restrict to VPC.
What should I do if I get this DEA-C01 question wrong?
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related DEA-C01 NAT questions on configuration and troubleshooting.
What is the key concept behind this question?
Static NAT maps one inside address to one outside address.
About these practice questions
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These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A data engineer is configuring S3 bucket policies to restrict access to a specific VPC. Which condition key should be used in the bucket policy to enforce that requests originate only from the desired VPC?
medium
A.aws:VpcSourceIp
✓ B.aws:SourceVpc
C.aws:RequestedRegion
D.aws:SourceIp
Why B: Option C is correct because aws:SourceVpc is the condition key used to restrict access to a specific VPC. Option A is wrong because aws:SourceIp is for IP addresses. Option B is wrong because aws:VpcSourceIp is not a valid key. Option D is wrong because aws:RequestedRegion is for region restriction.
Last reviewed: Jun 20, 2026
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This DEA-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 DEA-C01 exam.
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