ANS-C01 Network Design Practice Question
A company is designing a VPC with public and private subnets. The private subnets need to access the internet for software updates but must not be directly accessible from the internet. Which AWS service should be used to provide internet access to instances in the private subnets?
⚠ Common exam trap
The ANS-C01 exam often tests the misconception that an internet gateway can be used in a private subnet by simply not assigning public IPs, but the trap is that an internet gateway requires the subnet to have a route to it and instances must have public IPs for return traffic to work, which would expose them to inbound internet traffic.
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 a private subnet to initiate outbound traffic to the internet (e.g., for software updates) while preventing any unsolicited inbound traffic from the internet. It translates the private IP addresses of the instances to the NAT gateway's Elastic IP address using source network address translation (SNAT), and it does not maintain state for inbound connections that were not initiated from within the 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.
- ✗
Internet gateway
Why it's wrong here
Internet gateway is used for public subnets and allows inbound traffic.
- ✓
NAT gateway
Why this is correct
NAT gateway provides outbound-only internet access for private subnets.
- ✗
VPC endpoint
Why it's wrong here
VPC endpoint provides private access to AWS services, not the internet.
- ✗
Transit gateway
Why it's wrong here
Transit gateway connects VPCs and on-premises, not for internet access.
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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.