- A
/52
Why wrong: A /52 prefix uses 4 bits for subnetting (48+4=52), providing only 16 subnets (2^4). This is insufficient for 250 subnets.
- B
/56
A /56 prefix uses 8 bits for subnetting (48+8=56), providing 256 subnets (2^8). This meets the requirement of 250 subnets with minimal waste (6 unused subnets).
- C
/64
Why wrong: A /64 prefix uses 16 bits for subnetting (48+16=64), providing 65,536 subnets. While it works, it wastes many subnet IDs and is not minimal for 250 subnets. Also, /64 is typically used for end-user subnets, not as a subnetting strategy from a /48.
- D
/60
Why wrong: A /60 prefix uses 12 bits for subnetting (48+12=60), providing 4,096 subnets. This exceeds the requirement significantly and wastes more than a /56 would.
Question 55 of 520
N10-009 Networking Concepts Practice Question
This N10-009 practice question tests your understanding of networking concepts. 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 network engineer is designing a new IPv6 addressing scheme. The company has been assigned a /48 prefix and needs to support up to 250 subnets. Which subnet size should be used to minimize waste while meeting 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.
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
✓
/56
A /56 subnet provides 256 subnets (2^(56-48) = 2^8 = 256), which meets the requirement of up to 250 subnets with minimal waste. A /48 prefix is the site-level allocation, and using a /56 subnet mask leaves 8 bits for subnetting, offering exactly the needed capacity without over-allocating address space.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
/52
Why it's wrong here
A /52 prefix uses 4 bits for subnetting (48+4=52), providing only 16 subnets (2^4). This is insufficient for 250 subnets.
When this WOULD be correct
If the requirement were to support up to 16 subnets, a /52 would be the correct choice to minimize waste.
- ✓
/56
Why this is correct
A /56 prefix uses 8 bits for subnetting (48+8=56), providing 256 subnets (2^8). This meets the requirement of 250 subnets with minimal waste (6 unused subnets).
Clue confirmation
The clue word "minimum / minimize" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
/64
Why it's wrong here
A /64 prefix uses 16 bits for subnetting (48+16=64), providing 65,536 subnets. While it works, it wastes many subnet IDs and is not minimal for 250 subnets. Also, /64 is typically used for end-user subnets, not as a subnetting strategy from a /48.
When this WOULD be correct
If the question required each subnet to support SLAAC (Stateless Address Autoconfiguration) or needed a standard subnet size for end-user networks, /64 is the correct choice because IPv6 standards mandate /64 for SLAAC.
- ✗
/60
Why it's wrong here
A /60 prefix uses 12 bits for subnetting (48+12=60), providing 4,096 subnets. This exceeds the requirement significantly and wastes more than a /56 would.
When this WOULD be correct
If the requirement were to support up to 4000 subnets, a /60 would be correct because it provides 4096 subnets, meeting the need with minimal waste compared to larger subnet sizes like /64.
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 N10-009 exam frequently reuses these exact scenarios with slightly different constraints.
✓/56Correct answer▾
Why this is correct
A /56 prefix uses 8 bits for subnetting (48+8=56), providing 256 subnets (2^8). This meets the requirement of 250 subnets with minimal waste (6 unused subnets).
✗/52Wrong answer — click to see why▾
Why this is wrong here
A /52 prefix provides 16 subnets (2^(52-48)=16), which is insufficient for the requirement of up to 250 subnets.
★ When this WOULD be the correct answer
If the requirement were to support up to 16 subnets, a /52 would be the correct choice to minimize waste.
Why candidates choose this
Candidates may mistakenly think that a /52 offers more subnets than a /56 because it has a larger subnet portion, but they forget that the number of subnets is 2^(subnet bits), and /52 gives only 16 subnets, far fewer than needed.
✗/64Wrong answer — click to see why▾
Why this is wrong here
A /64 subnet provides 2^64 addresses per subnet, which is far more than needed for 250 subnets. Using /64 would waste a huge number of addresses and does not minimize waste given the /48 prefix.
★ When this WOULD be the correct answer
If the question required each subnet to support SLAAC (Stateless Address Autoconfiguration) or needed a standard subnet size for end-user networks, /64 is the correct choice because IPv6 standards mandate /64 for SLAAC.
Why candidates choose this
Candidates often default to /64 because it is the most common IPv6 subnet size and is required for SLAAC, forgetting that the question emphasizes minimizing waste for a specific number of subnets.
✗/60Wrong answer — click to see why▾
Why this is wrong here
A /60 subnet provides only 2^(60-48)=4096 subnets, which is far more than the required 250, but it wastes more addresses than a /56 (which gives 256 subnets). The question asks to minimize waste, so /56 is optimal.
★ When this WOULD be the correct answer
If the requirement were to support up to 4000 subnets, a /60 would be correct because it provides 4096 subnets, meeting the need with minimal waste compared to larger subnet sizes like /64.
Why candidates choose this
Candidates may think a larger subnet prefix (like /60) is more efficient because it provides more subnets, but they overlook that the requirement is only 250 subnets, so a /56 wastes fewer addresses overall.
Analysis generated from the official N10-009blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Common exam traps
Common exam trap: answer the scenario, not the keyword
The N10-009 exam often tests the misconception that /64 is the only valid subnet size in IPv6, but the question asks for subnet size to minimize waste for subnets, not for SLAAC, so candidates incorrectly choose /64 without considering the requirement for only 250 subnets.
Detailed technical explanation
How to think about this question
In IPv6, subnetting is performed by borrowing bits from the interface ID portion of the address, but the /64 boundary is critical for SLAAC (Stateless Address Autoconfiguration) as per RFC 4862. Using a /56 for site-level subnets is common in enterprise designs, as it balances granularity with simplicity, and many ISPs assign /56 prefixes to residential customers. The /48 prefix is typically the smallest allocation from a Regional Internet Registry (RIR) for a site, allowing flexible subnetting within the organization.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
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.
Visual reference
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
- →
Networking Concepts — study guide chapter
Learn the concepts, then practise the questions
- →
Networking Concepts practice questions
Targeted practice on this topic area only
- →
All N10-009 questions
520 questions across all exam domains
- →
CompTIA Network+ N10-009 study guide
Full concept coverage aligned to exam objectives
- →
N10-009 practice test guide
How to use practice tests most effectively before exam day
Related practice questions
Related N10-009 practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Networking Concepts practice questions
Practise N10-009 questions linked to Networking Concepts.
Network Implementation practice questions
Practise N10-009 questions linked to Network Implementation.
Network Operations practice questions
Practise N10-009 questions linked to Network Operations.
Network Security practice questions
Practise N10-009 questions linked to Network Security.
Network Troubleshooting practice questions
Practise N10-009 questions linked to Network Troubleshooting.
Network+ network fundamentals practice questions
Practise N10-009 questions linked to Network+ network fundamentals.
Practice this exam
Start a free N10-009 practice session
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
FAQ
Questions learners often ask
What does this N10-009 question test?
Networking Concepts — This question tests Networking Concepts — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: /56 — A /56 subnet provides 256 subnets (2^(56-48) = 2^8 = 256), which meets the requirement of up to 250 subnets with minimal waste. A /48 prefix is the site-level allocation, and using a /56 subnet mask leaves 8 bits for subnetting, offering exactly the needed capacity without over-allocating address space.
What should I do if I get this N10-009 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
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.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Keep practising
More N10-009 practice questions
- Which of the following network devices operates primarily at Layer 2 of the OSI model and uses MAC addresses to forward…
- Which of the following is a characteristic of UDP when compared to TCP?
- Which of the following IPv6 addresses is a valid link-local address?
- Which of the following security mechanisms requires a user to authenticate before gaining access to the wired network at…
- Which of the following network protocols operates at the Transport layer of the OSI model and provides connection-orient…
- Which of the following is a characteristic of a connectionless protocol at the transport layer?
Last reviewed: Jun 11, 2026
This N10-009 practice question is part of Courseiva's free CompTIA 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 N10-009 exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.