ANS-C01 Network Design Practice Question
A company wants to allow its VPC to access an S3 bucket securely without traversing the internet. Which AWS resource enables private connectivity between a VPC and S3?
⚠ Common exam trap
It's easy for candidates to confuse Gateway Endpoints with Interface Endpoints, assuming S3 requires an Interface Endpoint, but S3 only supports Gateway Endpoints for private connectivity.
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
✓
VPC Gateway Endpoint
A VPC Gateway Endpoint (C) is the correct choice because it provides private, direct connectivity between a VPC and S3 without traversing the internet. It uses AWS PrivateLink to route traffic through the AWS network, using prefix lists in the VPC route table to direct S3 traffic to the endpoint, ensuring data never leaves the AWS backbone.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Internet Gateway
Why it's wrong here
Internet Gateway exposes the VPC to the internet.
- ✗
AWS Site-to-Site VPN
Why it's wrong here
VPN is for on-premises connectivity to VPC.
- ✓
VPC Gateway Endpoint
Why this is correct
A VPC Gateway Endpoint uses AWS-managed route tables to direct S3 traffic through AWS’s internal network, bypassing the public internet entirely. This satisfies the company’s constraint of private connectivity by enabling access via prefix lists in the VPC’s route table, without requiring a NAT gateway, internet gateway, or VPN. The endpoint operates at the network layer, supporting only S3 and DynamoDB, and does not use private IP addresses or transit through a VPC’s subnet.
- ✗
NAT Gateway
Why it's wrong here
NAT Gateway enables outbound internet access, but S3 access would still traverse the internet.
Quick reference
AWS S3 Storage Class Comparison
| Storage Class | Min Duration | Retrieval | Use Case |
|---|---|---|---|
| S3 Standard | None | Immediate | Frequently accessed data |
| S3 Standard-IA | 30 days | Immediate | Infrequent access, rapid retrieval |
| S3 One Zone-IA | 30 days | Immediate | Non-critical infrequent data |
| S3 Intelligent-Tiering | None | Immediate–hours | Unknown or changing access patterns |
| S3 Glacier Instant | 90 days | Milliseconds | Archive with instant retrieval |
| S3 Glacier Flexible | 90 days | Minutes–hours | Archive, flexible retrieval |
| S3 Glacier Deep Archive | 180 days | Hours | Long-term compliance archive |
Go deeper
Related to this question
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Same concept, more angles
1 more way this is tested on ANS-C01
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. An application running on EC2 instances in a VPC needs to access an Amazon S3 bucket to read configuration files. The VPC has an S3 VPC endpoint configured. The instances are in a private subnet and have a security group that allows all outbound traffic. The bucket policy allows access from the VPC endpoint. However, the application fails to access the S3 bucket. What is the most likely cause?
medium- A.The network ACL for the private subnet is blocking outbound HTTPS traffic.
- ✓ B.The VPC endpoint's route table does not include the subnet's route table, so traffic to S3 is not routed through the endpoint.
- C.The security group for the EC2 instances has an outbound rule that blocks HTTPS traffic to S3.
- D.The S3 bucket policy does not grant access to the VPC endpoint's ID.
Why B: The most likely cause is that the VPC endpoint's route table does not include the subnet's route table, meaning traffic from the private subnet to S3 is not routed through the endpoint. Option B is correct because if the subnet's route table lacks a route for the S3 prefix list pointing to the VPC endpoint, traffic will go via a NAT gateway or internet gateway (if configured) or fail if no such connectivity exists. Option A is incorrect because network ACLs are not mentioned and typically allow outbound HTTPS. Option C is incorrect since the security group allows all outbound traffic. Option D is incorrect because the bucket policy already permits access from the VPC endpoint.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.