ANS-C01 Network Security, Compliance and Governance Practice Question
A company is designing a VPC with public and private subnets. The private subnets need to access Amazon S3 and Amazon DynamoDB. The company wants to minimize data transfer costs and avoid using a NAT gateway. What is the MOST cost-effective solution?
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 VPC endpoints for S3 and DynamoDB in the private subnets and update route tables
VPC endpoints for S3 and DynamoDB allow private connectivity without incurring data transfer costs or NAT gateway fees. Option A is wrong because an HTTP proxy adds complexity and cost. Option B is wrong because a NAT instance still incurs instance costs and management overhead. Option D is wrong because a NAT gateway incurs hourly and data processing charges.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Set up an HTTP proxy in the private subnets and configure the applications to use it
Why it's wrong here
An HTTP proxy in private subnets still requires a NAT gateway or internet gateway for outbound traffic to reach S3 and DynamoDB endpoints, incurring data transfer costs and defeating the cost-saving goal. This option is tempting because an HTTP proxy can cache frequently accessed data, reducing bandwidth in scenarios where applications make repeated web requests, but it does not provide the private, free connectivity to AWS services that VPC endpoints offer.
- ✗
Use a NAT instance instead of a NAT gateway
Why it's wrong here
NAT instance still incurs EC2 costs and management overhead.
- ✓
Create VPC endpoints for S3 and DynamoDB in the private subnets and update route tables
Why this is correct
VPC endpoints are free and provide private connectivity without NAT gateway.
- ✗
Create a NAT gateway in a public subnet and route private subnet traffic to it
Why it's wrong here
NAT gateway incurs 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.