ANS-C01 Network Security, Compliance and Governance Practice Question
A company is designing a VPC with public and private subnets. They need to allow instances in the private subnet to access the internet for software updates while preventing inbound internet traffic. Which AWS service should they use?
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
(NAT Gateway) is correct because a NAT Gateway allows instances in a private subnet to initiate outbound internet traffic (e.g., for software updates) while preventing any inbound traffic from the internet. Option B (AWS Direct Connect) is a dedicated private connection between on-premises and AWS, not for internet access. Option C (VPC Peering) connects VPCs privately, not providing internet access. Option D (Internet Gateway) allows both inbound and outbound traffic, which would expose private instances to inbound internet traffic, violating the requirement.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
NAT Gateway
Why this is correct
NAT Gateway enables outbound traffic to the internet from private subnets.
- ✗
AWS Direct Connect
Why it's wrong here
Direct Connect provides dedicated private connection, not internet access.
- ✗
VPC Peering
Why it's wrong here
VPC Peering connects VPCs, does not provide internet access.
- ✗
Internet Gateway
Why it's wrong here
An internet gateway enables bidirectional communication, allowing inbound traffic from the internet to reach the VPC, which directly violates the requirement to prevent inbound internet traffic. It is tempting because an internet gateway is the standard component for outbound-only internet access in a public subnet, but for a private subnet, a NAT gateway or NAT instance is required to translate private IP addresses without exposing instances to unsolicited inbound connections.
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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.