The correct answer is aws:SourceAccount, which is the bucket policy condition key specifically designed to restrict S3 bucket access to a single AWS account. This condition evaluates the account ID from which the request originates, ensuring that only principals within that account—regardless of the specific user or role—can read objects. On the AWS Certified Advanced Networking Specialty ANS-C01 exam, this concept tests your understanding of cross-account access controls and the subtle distinction between source-based and principal-based conditions. A common trap is confusing aws:SourceAccount with aws:PrincipalAccount, but the latter is not a valid condition key; similarly, aws:SourceArn is used for services like SNS or SQS, not for account-level restrictions. To remember this, think of “Source” as the origin of the request—the account sending the traffic—while “Principal” refers to the identity making the call, which is why aws:SourceAccount is the precise tool for locking down a bucket to a specific AWS account.
ANS-C01 Network Security, Compliance and Governance Practice Question
This ANS-C01 practice question tests your understanding of network security, compliance and governance. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. 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 wants to restrict access to an S3 bucket so that only requests originating from a specific AWS account can read objects. Which bucket policy condition should be used?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
aws:SourceAccount
Option A is correct because aws:SourceAccount is the condition key for specifying the source account. Option B is wrong because aws:SourceArn is for services like SNS. Option C is wrong because aws:PrincipalAccount is not a valid condition key. Option D is wrong because aws:Referer is for HTTP referer header.
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.
✗
aws:Referer
Why it's wrong here
This condition key is based on the HTTP referer header, not account.
✗
aws:PrincipalAccount
Why it's wrong here
This is not a valid condition key; use aws:SourceAccount or aws:PrincipalOrgID.
✓
aws:SourceAccount
Why this is correct
This condition key is used to restrict access based on the account that owns the resource making the request.
Related concept
Static NAT maps one inside address to one outside address.
✗
aws:SourceArn
Why it's wrong here
This condition key is used for services that pass an ARN, such as SNS or SQS.
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 ANS-C01 NAT questions on configuration and troubleshooting.
Network Security, Compliance and Governance — This question tests Network Security, Compliance and Governance — Static NAT maps one inside address to one outside address..
What is the correct answer to this question?
The correct answer is: aws:SourceAccount — Option A is correct because aws:SourceAccount is the condition key for specifying the source account. Option B is wrong because aws:SourceArn is for services like SNS. Option C is wrong because aws:PrincipalAccount is not a valid condition key. Option D is wrong because aws:Referer is for HTTP referer header.
What should I do if I get this ANS-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 ANS-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 company wants to restrict access to an S3 bucket so that only traffic from a specific AWS account is allowed. Which S3 bucket policy condition key should be used to achieve this?
medium
A.aws:PrincipalAccount
B.aws:Referer
✓ C.aws:SourceAccount
D.aws:SourceArn
Why C: Using the 'aws:SourceAccount' condition key ensures that only requests originating from the specified AWS account are allowed. Option A is wrong because 'aws:PrincipalAccount' checks the principal's account, not the source account. Option B is wrong because 'aws:SourceArn' checks the ARN of the source resource. Option D is wrong because 'aws:Referer' checks the HTTP referer header.
Last reviewed: Jun 20, 2026
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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.
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