Question 1,655 of 1,705
Network Security, Compliance and GovernancemediumMultiple ChoiceObjective-mapped

Restrict S3 Bucket Access to VPC Endpoint

This ANS-C01 practice question tests your understanding of network security, compliance and governance. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. A key principle to apply: aws:SourceVpce condition key. 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 using AWS CloudFormation to deploy a stack that includes an S3 bucket with a bucket policy that restricts access to a specific VPC endpoint. The stack fails to create, and the error indicates that the bucket policy contains an invalid principal. Which principal should be used to restrict access to a VPC endpoint?

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

The condition key aws:SourceVpce

The question asks for a 'principal' to restrict access to a VPC endpoint, but technically you cannot use a VPC endpoint as a principal in an S3 bucket policy. Instead, S3 bucket policies use the `aws:SourceVpce` condition key in the `Condition` element to restrict access to a specific VPC endpoint by specifying its ID. While `aws:SourceVpce` is not a principal, it is the correct and recommended method. Option A is the correct choice because it identifies the condition key used for this purpose. Option B (VPC ID) is incorrect because you need the VPC endpoint ID, not the VPC ID. Option C (ARN of the VPC endpoint) is incorrect because ARNs are not used as principals in this context. Option D (VPC endpoint service) is incorrect because the endpoint service is not a principal.

Key principle: aws:SourceVpce condition key

Answer analysis

Option-by-option breakdown

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

  • The condition key aws:SourceVpce

    Why this is correct

    Correct. `aws:SourceVpce` is a condition key, not a principal, but it is the standard way to restrict access to a specific VPC endpoint in an S3 bucket policy. The question's phrasing is technically imprecise; the correct method uses this condition key in the Condition element.

    Related concept

    aws:SourceVpce condition key

  • The VPC ID

    Why it's wrong here

    Incorrect. The VPC ID alone cannot be used to restrict access; you must specify the VPC endpoint ID using the `aws:SourceVpce` condition key.

  • The ARN of the VPC endpoint

    Why it's wrong here

    Incorrect. The ARN of the VPC endpoint is not used as a principal or condition key in S3 bucket policies for this purpose.

  • The VPC endpoint service

    Why it's wrong here

    Incorrect. A VPC endpoint service is not a principal and is not used in S3 bucket policies to restrict access to a specific endpoint.

Common exam traps

Common exam trap: answer the scenario, not the keyword

The question deliberately uses the word 'principal' to mislead. The correct approach uses a condition key (`aws:SourceVpce`), not a principal. Candidates often choose the VPC endpoint ARN or ID thinking they are principals.

Detailed technical explanation

How to think about this question

Treat this as a scenario question. Identify the problem, the constraint, and the best action. Then compare each option against those facts.

KKey Concepts to Remember

  • aws:SourceVpce condition key
  • Principal vs Condition

TExam Day Tips

  • Watch for words such as best, first, most likely and least administrative effort.
  • Review why wrong options are wrong, not only why the correct option is correct.

Key takeaway

aws:SourceVpce condition key

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.

Quick reference

AWS S3 Storage Class Comparison

Storage ClassMin DurationRetrievalUse Case
S3 StandardNoneImmediateFrequently accessed data
S3 Standard-IA30 daysImmediateInfrequent access, rapid retrieval
S3 One Zone-IA30 daysImmediateNon-critical infrequent data
S3 Intelligent-TieringNoneImmediate–hoursUnknown or changing access patterns
S3 Glacier Instant90 daysMillisecondsArchive with instant retrieval
S3 Glacier Flexible90 daysMinutes–hoursArchive, flexible retrieval
S3 Glacier Deep Archive180 daysHoursLong-term compliance archive

What to study next

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FAQ

Questions learners often ask

What does this ANS-C01 question test?

Network Security, Compliance and Governance — This question tests Network Security, Compliance and Governance — aws:SourceVpce condition key.

What is the correct answer to this question?

The correct answer is: The condition key aws:SourceVpce — The question asks for a 'principal' to restrict access to a VPC endpoint, but technically you cannot use a VPC endpoint as a principal in an S3 bucket policy. Instead, S3 bucket policies use the `aws:SourceVpce` condition key in the `Condition` element to restrict access to a specific VPC endpoint by specifying its ID. While `aws:SourceVpce` is not a principal, it is the correct and recommended method. Option A is the correct choice because it identifies the condition key used for this purpose. Option B (VPC ID) is incorrect because you need the VPC endpoint ID, not the VPC ID. Option C (ARN of the VPC endpoint) is incorrect because ARNs are not used as principals in this context. Option D (VPC endpoint service) is incorrect because the endpoint service is not a principal.

What should I do if I get this ANS-C01 question wrong?

Review aws:SourceVpce condition key, then practise related ANS-C01 questions on the same topic to reinforce the concept.

What is the key concept behind this question?

aws:SourceVpce condition key

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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.