ANS-C01 Network Design Practice Question
An application running on EC2 instances in a private subnet needs to download patches from the internet. The VPC has an internet gateway and public subnets. Which resource should be used to provide outbound internet access to the instances?
⚠ Common exam trap
AWS often tests the misconception that an internet gateway can be placed in a private subnet or that a VPC endpoint can provide general internet access, but the key trap here is confusing a VPC gateway endpoint (which only works for specific AWS services like S3 and DynamoDB) with a NAT gateway that provides full outbound internet 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
✓
NAT gateway in a public subnet
A NAT gateway in a public subnet provides outbound-only internet access to instances in private subnets by translating their private IP addresses to the NAT gateway's Elastic IP address. This allows the EC2 instances to download patches from the internet while preventing any unsolicited inbound connections from the internet, which is the standard design for secure outbound internet access in a VPC.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
VPC gateway endpoint for S3
Why it's wrong here
Only for S3 and DynamoDB, not general internet access.
- ✓
NAT gateway in a public subnet
Why this is correct
Provides outbound internet access for private instances.
- ✗
AWS Site-to-Site VPN connection
Why it's wrong here
For connecting on-premises networks, not internet access.
- ✗
Internet gateway in the private subnet
Why it's wrong here
Would expose instances to inbound internet traffic.
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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.