ANS-C01 Network Implementation Practice Question
A company has a VPC with public and private subnets in two Availability Zones. The company hosts a web application on EC2 instances in the private subnets. The application needs to access an S3 bucket. What is the MOST cost-effective and secure way to provide this access?
⚠ Common exam trap
Many candidates confuse VPC Gateway Endpoints with Interface Endpoints or assume a NAT Gateway is required for private subnet internet access, overlooking that S3 can be accessed privately and cost-effectively via a Gateway Endpoint without any NAT or internet gateway.
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
✓
Create a VPC Gateway Endpoint for S3 and attach it to the private subnet route tables.
A VPC Gateway Endpoint for S3 provides private, secure connectivity to S3 without traversing the public internet, and it incurs no hourly or data processing charges, making it the most cost-effective and secure choice. Traffic stays within the AWS network, and the endpoint is attached to the private subnet route tables, allowing EC2 instances in those subnets to access S3 directly without needing a NAT Gateway or public IPs.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Deploy a NAT Gateway in each public subnet and route traffic from private subnets through it.
Why it's wrong here
Incurs hourly and data processing charges.
- ✗
Use AWS Transit Gateway to route traffic to S3 via a centralized VPN.
Why it's wrong here
Over-engineered and costly for a single VPC.
- ✗
Attach an Internet Gateway to the VPC and assign public IPs to the EC2 instances.
Why it's wrong here
Exposes instances to the internet, less secure.
- ✓
Create a VPC Gateway Endpoint for S3 and attach it to the private subnet route tables.
Why this is correct
Cost-effective and secure; no data transfer costs.
Visual reference
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
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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.