ANS-C01 Network Implementation Practice Question
A company is deploying a new application in a VPC with public and private subnets. The application servers in the private subnets need to access the internet to download patches. Which configuration meets this requirement without allowing inbound internet traffic?
⚠ Common exam trap
Many candidates confuse a NAT gateway with an internet gateway, assuming both provide internet access, but an internet gateway enables bidirectional traffic (including inbound), while a NAT gateway strictly enforces outbound-only access from private subnets.
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 NAT gateway in a public subnet and add a route to the NAT gateway from the private subnets' route tables.
A NAT gateway in a public subnet allows instances in private subnets to initiate outbound connections to the internet (e.g., for patch downloads) while preventing unsolicited inbound traffic from the internet. The private subnet's route table must have a default route (0.0.0.0/0) pointing to the NAT gateway's elastic network interface. This is the standard AWS pattern for outbound-only internet access from private subnets.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Attach an internet gateway to the private subnets and configure route tables accordingly.
Why it's wrong here
An internet gateway in a private subnet would expose instances to inbound internet traffic, violating the requirement to block inbound traffic.
- ✓
Create a NAT gateway in a public subnet and add a route to the NAT gateway from the private subnets' route tables.
Why this is correct
A NAT gateway allows outbound internet traffic from private subnets while preventing unsolicited inbound connections.
- ✗
Establish a site-to-site VPN connection to an on-premises internet gateway.
Why it's wrong here
A VPN connection provides private connectivity to a remote network, not direct internet access.
- ✗
Configure a VPC endpoint for the internet in the private subnets.
Why it's wrong here
VPC endpoints provide private connectivity to AWS services, not general internet access.
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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.