N10-009 Networking Concepts Practice Question
An IPv6 address has the prefix 2001:db8::/32. Which of the following IP addresses belongs to the same prefix?
⚠ Common exam trap
The N10-009 exam often tests the misconception that the double-colon (::) compresses the prefix itself, leading candidates to incorrectly assume that 2001:db8::/32 matches any address starting with 2001:db8, even if the second hextet is altered (e.g., 2001:db9 or 2001:db7).
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
✓
2001:db8:1::1
The prefix 2001:db8::/32 means the first 32 bits of the address must be 2001:0db8. Option A (2001:db8:1::1) expands to 2001:0db8:0001:0000:0000:0000:0000:0001, which matches the first 32 bits exactly, so it belongs to the same /32 prefix.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
2001:db8:1::1
Why this is correct
This address, 2001:db8:1::1, precisely matches the 2001:db8 portion of the given /32 prefix in its first two hextets. The prefix 2001:db8::/32 dictates that any address beginning with 2001:db8 belongs to this network. Since the first 32 bits of 2001:db8:1::1 are indeed 2001:0db8, it is correctly identified as being within the specified network range, making it a valid address for this prefix.
- ✗
2001:db9::1
Why it's wrong here
The address 2001:db9::1 has 2001:0db9 as its initial 32 bits. This value does not align with the 2001:db8 requirement of the /32 prefix. The discrepancy in the second 16-bit hextet means this address is part of a different network segment, distinct from the one defined by 2001:db8::/32, and would not be routable within that specific network.
When this WOULD be correct
If the question specified a prefix of 2001:db8::/28, then 2001:db9::1 would be within the same prefix because the first 28 bits (2001:0db) match, and the next nibble (8 vs 9) is part of the host portion.
- ✗
2001:db7::1
Why it's wrong here
The address 2001:db7::1 contains 2001:0db7 as its first 32 bits. This differs from the specified network prefix 2001:db8::/32, which requires the second 16-bit hextet to be exactly 'db8'. Because the second hextet does not match the prefix, this address falls outside the designated network range and therefore is not part of the same /32 prefix.
When this WOULD be correct
If the question specified a prefix of 2001:db7::/32, then 2001:db7::1 would be a correct address belonging to that prefix.
- ✗
fe80::1
Why it's wrong here
The address fe80::1 is an IPv6 link-local address, which is automatically configured on interfaces for communication only within the local network segment. Link-local addresses are specifically defined by the fe80::/10 prefix, indicating that their first 10 bits are 1111111010. This distinct prefix fundamentally differs from 2001:db8::/32, making fe80::1 completely unrelated to the specified global unicast network and thus an incorrect option.
When this WOULD be correct
In a question asking for a link-local IPv6 address, fe80::1 would be correct. For example, 'Which of the following is a valid link-local unicast address?'
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.
✓2001:db8:1::1Correct answer▾
Why this is correct
This address, 2001:db8:1::1, precisely matches the 2001:db8 portion of the given /32 prefix in its first two hextets. The prefix 2001:db8::/32 dictates that any address beginning with 2001:db8 belongs to this network. Since the first 32 bits of 2001:db8:1::1 are indeed 2001:0db8, it is correctly identified as being within the specified network range, making it a valid address for this prefix.
✗2001:db9::1Wrong answer — click to see why▾
Why this is wrong here
The prefix 2001:db8::/32 includes addresses where the first 32 bits are 2001:0db8. Option B, 2001:db9::1, has the third quartet as 0db9, which differs in the 33rd bit, so it is not within the /32 prefix.
★ When this WOULD be the correct answer
If the question specified a prefix of 2001:db8::/28, then 2001:db9::1 would be within the same prefix because the first 28 bits (2001:0db) match, and the next nibble (8 vs 9) is part of the host portion.
Why candidates choose this
Candidates may mistakenly think that only the first two quartets (2001:db8) define the prefix, ignoring that the /32 prefix includes the entire third quartet, so any change in the third quartet (like db9) is outside the prefix.
✗2001:db7::1Wrong answer — click to see why▾
Why this is wrong here
The prefix 2001:db8::/32 includes addresses where the first 32 bits are 2001:0db8. Option C (2001:db7::1) has the third hextet as db7, which differs from db8 in the 33rd bit, so it does not match the /32 prefix.
★ When this WOULD be the correct answer
If the question specified a prefix of 2001:db7::/32, then 2001:db7::1 would be a correct address belonging to that prefix.
Why candidates choose this
Candidates may confuse the prefix length and think that only the first two hextets matter, or they may misread db7 as db8 due to visual similarity.
✗fe80::1Wrong answer — click to see why▾
Why this is wrong here
The prefix 2001:db8::/32 specifies that the first 32 bits must be 2001:0db8. Option D (fe80::1) starts with fe80, which is a link-local address prefix, not matching the required prefix.
★ When this WOULD be the correct answer
In a question asking for a link-local IPv6 address, fe80::1 would be correct. For example, 'Which of the following is a valid link-local unicast address?'
Why candidates choose this
Candidates may confuse different IPv6 address types (global unicast vs. link-local) or misremember the prefix ranges, thinking fe80 falls within the 2001::/16 range.
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?”
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IPv4 and IPv6 Addressing
Key term
IPv6 address
An IPv6 address is a 128-bit numeric label used to identify a device on an Internet Protocol network, designed to replace IPv4 due to the exhaustion of available addresses.
Key term
IPv6
IPv6 is the most recent version of the Internet Protocol, designed to replace IPv4 by providing a vastly larger number of unique addresses and improved network features.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.