Question 78 of 1,621
ANS-C01 Network Implementation Practice Question
A company is deploying a VPC with public and private subnets in two Availability Zones. The public subnets host NAT gateways for outbound internet access from the private subnets. Which configuration ensures that EC2 instances in the private subnets can route traffic to the internet through the NAT gateways?
⚠ Common exam trap
Test-takers frequently confuse the direction of routing and think a route in the public subnet (Option A) or an egress-only gateway (Option B) can serve private IPv4 traffic, when in fact the private subnet must explicitly route to the NAT gateway.
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
✓
Add a route in the private subnet route table with destination 0.0.0.0/0 targeting the NAT gateway.
For EC2 instances in private subnets to reach the internet via a NAT gateway, the private subnet route table must include a default route (0.0.0.0/0) pointing to the NAT gateway as the next hop. The NAT gateway resides in a public subnet and translates the private IPs to its own Elastic IP, forwarding traffic to the internet gateway. Without this route, traffic from private instances has no path to the NAT gateway.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Add a route in the public subnet route table pointing to the internet gateway.
Why it's wrong here
Public subnets already have such routes; private subnets need NAT gateway route.
- ✗
Attach an egress-only internet gateway to the private subnets.
Why it's wrong here
Egress-only internet gateways are for IPv6 traffic only.
- ✗
Create a VPC peering connection between the VPC and the NAT gateway.
Why it's wrong here
VPC peering is not used for internet access.
- ✓
Add a route in the private subnet route table with destination 0.0.0.0/0 targeting the NAT gateway.
Why this is correct
This enables outbound internet access from private instances via NAT.
Visual reference
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Last reviewed: Jul 4, 2026
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.
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