Question 16 of 1,621
ANS-C01 Network Design Practice Question
A company has a VPC with a CIDR of 10.0.0.0/16. The company needs to add a new subnet for a container cluster that requires at least 2000 IP addresses. Which TWO subnet CIDR blocks meet this requirement? (Choose two.)
⚠ Common exam trap
AWS often tests the misconception that a /24 subnet (256 addresses) is sufficient for 2000 IPs, or that candidates forget to calculate total addresses as 2^(32-prefix) and instead guess based on the prefix number alone.
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
✓
10.0.0.0/20
(10.0.0.0/20) provides 2^(32-20) = 4096 IP addresses, and option D (10.0.0.0/21) provides 2^(32-21) = 2048 IP addresses. Both meet the requirement of at least 2000 usable IP addresses (after subtracting AWS reserved addresses, each still offers well over 2000).
Answer analysis
Option-by-option breakdown
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
Only 256 addresses.
- ✗
10.0.0.0/25
Why it's wrong here
128 addresses.
- ✓
10.0.0.0/20
Why this is correct
4096 addresses, more than 2000.
- ✓
10.0.0.0/21
Why this is correct
2048 addresses, meets requirement.
- ✗
10.0.0.0/26
Why it's wrong here
64 addresses.
Visual reference
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Last reviewed: Jun 30, 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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