ANS-C01 Network Security, Compliance and Governance Practice Question
A company has deployed a VPC with public and private subnets. They have an Internet Gateway attached to the VPC and a NAT Gateway in the public subnet. The private subnet instances need to download patches from the internet. Which configuration ensures that the private instances can reach the internet while preventing inbound traffic from the internet?
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
✓
Add a route in the private subnet route table pointing 0.0.0.0/0 to the NAT Gateway.
Adding a route in the private subnet route table pointing 0.0.0.0/0 to the NAT Gateway allows private instances to initiate outbound traffic to the internet while preventing inbound connections from the internet. Option A is incorrect because a VPC Gateway Endpoint only provides access to specific AWS services (e.g., S3, DynamoDB), not general internet traffic. Option B is incorrect because routing 0.0.0.0/0 to the Internet Gateway would expose the private instances to inbound traffic from the internet (assuming the route is in the private subnet route table, it would still allow inbound traffic if the instances have public IPs, but more importantly, it bypasses the NAT Gateway's security). Option D is incorrect because VPC Peering does not provide internet access; it only connects two VPCs.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Add a VPC Gateway Endpoint for Amazon S3 to the private subnet route table.
Why it's wrong here
Gateway Endpoints only provide private access to specific AWS services, not general internet access.
- ✗
Add a route in the private subnet route table pointing 0.0.0.0/0 to the Internet Gateway.
Why it's wrong here
Internet Gateway allows inbound traffic, which violates security requirements.
- ✓
Add a route in the private subnet route table pointing 0.0.0.0/0 to the NAT Gateway.
Why this is correct
NAT Gateway allows outbound traffic to the internet and blocks unsolicited inbound traffic.
- ✗
Create a VPC Peering connection to a public VPC and route traffic through it.
Why it's wrong here
VPC Peering does not provide internet access; it only connects VPCs privately.
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.