CCNA Network Infrastructure and Connectivity Practice Question
A subnet must support at least 62 usable hosts. Which prefix will create the smallest subnet that meets the requirement?
⚠ Common exam trap
Ensure you calculate usable hosts, not total addresses. Remember that network and broadcast addresses are not usable.
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
✓
/26
To support at least 62 usable hosts, the subnet needs 64 total addresses, because two of those will be reserved for the network and broadcast addresses. In plain language, the target is not 62 total addresses; it is 62 usable ones after the two reserved values are taken away. A /26 provides exactly 64 total addresses and therefore 62 usable host addresses. This is a classic minimum-prefix question because it checks whether you can convert a host requirement into the correct power-of-two subnet size without over-allocating unnecessarily. A /27 would be too small, while /25 would work but would waste more addresses than needed. The smallest valid prefix is /26.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
/27
Why it's wrong here
This is wrong because a /27 provides only 30 usable host addresses.
When this WOULD be correct
If the question specified a requirement for at least 30 usable hosts, then a /27 would be the correct answer, as it accommodates exactly 30 usable addresses.
- ✓
/26
Why this is correct
This is correct because a /26 provides 64 total addresses and 62 usable hosts.
- ✗
/25
Why it's wrong here
This is wrong because /25 works but is larger than necessary.
When this WOULD be correct
In a scenario where the question specifies a need for at least 126 usable hosts, a /25 subnet would be the correct answer, as it meets the requirement without exceeding it unnecessarily.
- ✗
/24
Why it's wrong here
This is wrong because /24 is much larger than required.
When this WOULD be correct
If the question asked for a subnet that supports at least 254 usable hosts, then /24 would be the correct answer, as it provides the necessary number of usable addresses without exceeding the requirement.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The 200-301 exam frequently reuses these exact scenarios with slightly different constraints.
✓/26Correct answer▾
Why this is correct
This is correct because a /26 provides 64 total addresses and 62 usable hosts.
✗/27Wrong answer — click to see why▾
Why this is wrong here
A /27 prefix provides only 32 total addresses (2^(32-27)=32), with 30 usable hosts after subtracting network and broadcast addresses. This is insufficient for the requirement of at least 62 usable hosts.
★ When this WOULD be the correct answer
If the question specified a requirement for at least 30 usable hosts, then a /27 would be the correct answer, as it accommodates exactly 30 usable addresses.
Why candidates choose this
Students may mistakenly think that a /27 is sufficient because they forget to subtract the network and broadcast addresses, or they confuse the number of total addresses with usable hosts.
✗/25Wrong answer — click to see why▾
Why this is wrong here
A /25 prefix provides 128 total addresses and 126 usable hosts, which is more than required. While it meets the requirement, it is not the smallest prefix, leading to wasted IP addresses in a subnet.
★ When this WOULD be the correct answer
In a scenario where the question specifies a need for at least 126 usable hosts, a /25 subnet would be the correct answer, as it meets the requirement without exceeding it unnecessarily.
Why candidates choose this
Students might choose /25 because it clearly provides enough hosts, but they overlook the requirement for the smallest prefix that meets the need, which is a common exam trap.
✗/24Wrong answer — click to see why▾
Why this is wrong here
A /24 prefix provides 256 total addresses and 254 usable hosts, far exceeding the requirement of 62 usable hosts. This is not the smallest prefix and results in significant waste of IP address space.
★ When this WOULD be the correct answer
If the question asked for a subnet that supports at least 254 usable hosts, then /24 would be the correct answer, as it provides the necessary number of usable addresses without exceeding the requirement.
Why candidates choose this
Students may default to /24 as a common subnet size without calculating the exact requirement, or they may not understand the concept of choosing the smallest prefix that satisfies the host count.
Analysis generated from the official 200-301blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Visual reference
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Related to this question
Learn chapter
Collision Domains and Broadcast Domains
Key term
CAN
A CAN (Controller Area Network) is a robust vehicle bus standard designed to allow microcontrollers and devices to communicate with each other without a host computer.
Key term
Usable hosts
Usable hosts are the IP addresses in a subnet that can actually be assigned to devices like computers, printers, or servers, excluding the network and broadcast addresses.
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Courseiva writes every 200-301 question from scratch — 1,389 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 200-301 practice question is part of Courseiva's free Cisco 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 200-301 exam.