ANS-C01 Network Design Practice Question
A company has a VPC with public and private subnets. The private subnets need to access the internet for software updates. The company wants to minimize cost and management overhead. Which solution should be used?
⚠ Common exam trap
Many exam-takers choose Option A (NAT Gateway in each AZ) assuming high availability is mandatory, but the question explicitly prioritizes minimizing cost and management overhead, making a single NAT Gateway the correct choice despite the availability trade-off.
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
✓
Deploy a single NAT Gateway in one public subnet and configure route tables to route 0.0.0.0/0 traffic to it.
A single NAT Gateway in one public subnet provides outbound internet access for private subnets with lower cost and management overhead than multiple NAT Gateways or NAT instances. NAT Gateway is a managed AWS service that automatically handles failover within its Availability Zone, and routing private subnet traffic to it via a 0.0.0.0/0 route allows instances to reach the internet for software updates while remaining unreachable from the internet.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Deploy a NAT Gateway in each Availability Zone for high availability.
Why it's wrong here
This is more expensive and not necessary if AZ failure is acceptable.
- ✗
Launch a NAT instance in a public subnet and configure routing.
Why it's wrong here
NAT instance requires manual management and is less reliable than NAT Gateway.
- ✗
Attach an Internet Gateway to the VPC and add a default route pointing to the IGW in private subnets.
Why it's wrong here
Private subnets cannot route directly to IGW; they need a NAT device.
- ✓
Deploy a single NAT Gateway in one public subnet and configure route tables to route 0.0.0.0/0 traffic to it.
Why this is correct
A single NAT Gateway provides internet access for all private subnets with minimal cost and management.
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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.