This N10-009 practice question tests your understanding of network implementation. 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. A key principle to apply: a /26 subnet mask uses 26 bits for the network portion.. 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 network engineer is designing a subnet for a department that requires exactly 50 usable host addresses. Which subnet mask provides the minimum number of usable host addresses while still accommodating the requirement?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "minimum / minimize"
Why it matters: Asks for the least resource use — fewest addresses, smallest subnet, lowest overhead. Eliminate over-provisioned options even if they would technically work.
/26
A /26 provides 64 total addresses (62 usable), which is the smallest subnet that can accommodate 50 hosts.
/27
Why wrong: A /27 provides only 32 total addresses (30 usable), which is insufficient for 50 hosts.
/28
Why wrong: A /28 provides only 16 total addresses (14 usable), far too few for 50 hosts.
/25
Why wrong: A /25 provides 128 total addresses (126 usable), which is more than needed and not the minimum.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
/26
A /26 subnet mask (255.255.255.192) provides 2^(32-26) = 64 total addresses, of which 62 are usable (subtracting network and broadcast addresses). This is the smallest subnet that meets the requirement of exactly 50 usable hosts, as /27 yields only 30 usable addresses and /28 yields only 14, while /25 provides 126 usable addresses, which is more than necessary.
Key principle: A /26 subnet mask uses 26 bits for the network portion.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
/26
Why this is correct
A /26 provides 64 total addresses (62 usable), which is the smallest subnet that can accommodate 50 hosts.
Clue confirmation
The clue word "minimum / minimize" in the question point toward this answer.
Related concept
A /26 subnet mask uses 26 bits for the network portion.
/27
Why it's wrong here
A /27 provides only 32 total addresses (30 usable), which is insufficient for 50 hosts.
/28
Why it's wrong here
A /28 provides only 16 total addresses (14 usable), far too few for 50 hosts.
/25
Why it's wrong here
A /25 provides 128 total addresses (126 usable), which is more than needed and not the minimum.
Common exam traps
CompTIA often tests the confusion between total addresses and usable addresses, where candidates mistakenly think a /27 (32 total addresses) can support 50 hosts, or they forget to subtract the network and broadcast addresses from the total.
Detailed technical explanation
The usable host count is always total addresses minus 2 (network and broadcast addresses), as defined in RFC 950 for IPv4 subnetting. In real-world scenarios, network engineers must also consider future growth; however, this question strictly tests the ability to calculate the smallest subnet that meets a given host requirement. The formula 2^(32 - prefix_length) - 2 is fundamental for subnetting calculations in the N10-009 exam.
Key takeaway
A /26 subnet mask uses 26 bits for the network portion.
Real-world example
A network engineer segments a warehouse floor into three subnets: 20 scanners, 5 printers, and 2 management hosts. Picking the wrong mask wastes addresses or leaves too few usable hosts. Exam questions test whether you can apply CIDR notation, calculate block size, and identify the correct usable-host range for a given prefix.
What to study next
Review a /26 subnet mask uses 26 bits for the network portion., then practise related N10-009 questions on the same topic to reinforce the concept.
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FAQ
Network Implementation — This question tests Network Implementation — A /26 subnet mask uses 26 bits for the network portion..
The correct answer is: /26 — A /26 subnet mask (255.255.255.192) provides 2^(32-26) = 64 total addresses, of which 62 are usable (subtracting network and broadcast addresses). This is the smallest subnet that meets the requirement of exactly 50 usable hosts, as /27 yields only 30 usable addresses and /28 yields only 14, while /25 provides 126 usable addresses, which is more than necessary.
Review a /26 subnet mask uses 26 bits for the network portion., then practise related N10-009 questions on the same topic to reinforce the concept.
Yes — watch for: "minimum / minimize". Asks for the least resource use — fewest addresses, smallest subnet, lowest overhead. Eliminate over-provisioned options even if they would technically work.
A /26 subnet mask uses 26 bits for the network portion.
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Last reviewed: Jun 30, 2026
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