ANS-C01 Network Design Practice Question
A company is deploying an application that must use IPv6 for internet-facing traffic. The VPC is currently using IPv4 only. What is the simplest way to enable IPv6?
⚠ Common exam trap
Many exam-takers confuse the egress-only internet gateway (which is only for outbound IPv6 from private subnets) with the standard internet gateway, or mistakenly think a translation mechanism like NAT64 is required, when in fact the simplest solution is to add an IPv6 CIDR and route to the existing internet 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
✓
Associate an IPv6 CIDR block with the VPC and subnets, and update route tables to route IPv6 traffic to an internet gateway.
The simplest way to enable IPv6 in an existing IPv4-only VPC is to associate an IPv6 CIDR block (e.g., an Amazon-provided /56) with the VPC and subnets, then update the route tables to direct IPv6 traffic (::/0) to an internet gateway. This requires no additional translation or complex infrastructure, as the internet gateway is already dual-stack capable and can handle both IPv4 and IPv6 traffic natively.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Use an egress-only internet gateway for IPv6 traffic.
Why it's wrong here
Egress-only internet gateway is for outbound-only traffic; inbound traffic is not possible.
- ✓
Associate an IPv6 CIDR block with the VPC and subnets, and update route tables to route IPv6 traffic to an internet gateway.
Why this is correct
Simplest way to enable IPv6.
- ✗
Deploy a NAT64 device to translate IPv6 to IPv4.
Why it's wrong here
NAT64 is for translation, not native IPv6.
- ✗
Set up a VPN connection to an ISP that provides IPv6.
Why it's wrong here
VPN is not for internet-facing traffic.
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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.