This ANS-C01 practice question tests your understanding of network design. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A company has a VPC with an IPv4 CIDR of 10.0.0.0/16. It needs to add an additional non-overlapping CIDR for new workloads. Which CIDR should be used?
10.0.0.0/24
Why wrong: This is a subset of the existing CIDR.
10.1.0.0/16
This CIDR is outside the existing 10.0.0.0/16 range.
10.0.1.0/24
Why wrong: This is also a subset of the existing CIDR.
10.0.0.0/8
Why wrong: This includes the existing CIDR, causing overlap.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
10.1.0.0/16
Option B (10.1.0.0/16) is correct because it provides a non-overlapping CIDR block that does not conflict with the existing VPC CIDR of 10.0.0.0/16. In AWS, when adding a secondary CIDR to a VPC, the new block must not overlap with the existing VPC CIDR or any of its subnets. The 10.1.0.0/16 range is entirely separate from 10.0.0.0/16, satisfying this requirement.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
10.0.0.0/24
Why it's wrong here
This is a subset of the existing CIDR.
10.1.0.0/16
Why this is correct
This CIDR is outside the existing 10.0.0.0/16 range.
Related concept
Read the scenario before looking for a memorised answer.
10.0.1.0/24
Why it's wrong here
This is also a subset of the existing CIDR.
10.0.0.0/8
Why it's wrong here
This includes the existing CIDR, causing overlap.
Common exam traps
The trap here is that candidates often assume any non-overlapping private IP range is acceptable, but they overlook that the new CIDR must also be from the same RFC 1918 address space and not conflict with any existing subnets, not just the VPC CIDR itself.
Detailed technical explanation
When adding a secondary CIDR to an AWS VPC, the new block must be from the private IPv4 address ranges (RFC 1918) and must not overlap with the primary CIDR or any existing subnets. AWS validates the CIDR using longest prefix match logic; overlapping blocks are rejected with an error. This is commonly used to expand VPC capacity without rearchitecting, but careful planning is needed to avoid conflicts with peered VPCs or on-premises networks.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A healthcare organisation deploys an application with a public-facing web tier and a private database tier. The database subnet has no public IP and only accepts connections from the web tier's security group. Questions like this test whether you can design cloud network isolation using VNets/VPCs, subnets, and security group rules.
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FAQ
Network Design — This question tests Network Design — Read the scenario before looking for a memorised answer..
The correct answer is: 10.1.0.0/16 — Option B (10.1.0.0/16) is correct because it provides a non-overlapping CIDR block that does not conflict with the existing VPC CIDR of 10.0.0.0/16. In AWS, when adding a secondary CIDR to a VPC, the new block must not overlap with the existing VPC CIDR or any of its subnets. The 10.1.0.0/16 range is entirely separate from 10.0.0.0/16, satisfying this requirement.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 24, 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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