ANS-C01 Network Design Practice Question
A company has a VPC with an IPv4 CIDR block of 10.0.0.0/16. It needs to connect to an on-premises data center via AWS Direct Connect. The on-premises network uses 10.0.0.0/8. Which action should the network engineer take to avoid IP address overlap?
⚠ Common exam trap
The ANS-C01 exam often tests the misconception that a NAT gateway or Direct Connect gateway can magically resolve IP overlap, but neither provides NAT for private VIF traffic, and the only correct solution is to avoid overlapping CIDRs entirely.
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
✓
Create a new VPC with a non-overlapping CIDR block, such as 172.16.0.0/16, and migrate resources.
The VPC CIDR 10.0.0.0/16 is a subset of the on-premises 10.0.0.0/8, creating an overlap that prevents Direct Connect routing. AWS does not support overlapping IP spaces across a Direct Connect virtual interface; the only viable solution is to use a non-overlapping CIDR (e.g., 172.16.0.0/16) for the VPC and migrate resources to it.
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 a NAT gateway to translate the VPC addresses when connecting to on-premises.
Why it's wrong here
NAT does not resolve routing conflicts; the routes would still overlap.
- ✗
Use AWS Direct Connect gateway to automatically handle overlapping IPs.
Why it's wrong here
Direct Connect gateway does not resolve IP overlaps.
- ✗
Add a secondary CIDR block to the VPC and use it for resources that need to connect to on-premises.
Why it's wrong here
Secondary CIDR also must not overlap; the primary still overlaps.
- ✓
Create a new VPC with a non-overlapping CIDR block, such as 172.16.0.0/16, and migrate resources.
Why this is correct
Changing the VPC CIDR to a non-overlapping range solves the conflict.
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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.