ANS-C01 Network Implementation Practice Question
A company is deploying a VPC with public and private subnets in two Availability Zones. The private subnets need outbound internet access for software updates but must not be reachable from the internet. Which AWS service should be used to achieve this?
⚠ Common exam trap
A common mix-up: candidates confuse a NAT Gateway with an Internet Gateway, mistakenly thinking an Internet Gateway can be placed in a private subnet to provide outbound-only access, but an Internet Gateway is a VPC-level construct that always allows bidirectional traffic if a route to it exists.
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
A NAT Gateway enables instances in private subnets to initiate outbound IPv4 traffic to the internet (e.g., for software updates) while preventing the internet from initiating connections back to those instances. It resides in a public subnet with an Elastic IP and uses source network address translation (SNAT) to translate private source IPs to the gateway's public IP, ensuring the private instances remain unreachable from external hosts.
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 Peering
Why it's wrong here
VPC Peering connects VPCs privately, not for internet access.
- ✗
Virtual Private Gateway
Why it's wrong here
Virtual Private Gateway is used for VPN connections, not internet access.
- ✓
NAT Gateway
Why this is correct
NAT Gateway provides outbound internet access for private subnets without allowing unsolicited inbound connections.
- ✗
Internet Gateway
Why it's wrong here
Internet Gateway allows inbound traffic from the internet; private subnets would be reachable.
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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.