The correct answer is fe80::1 because IPv6 link-local addresses always begin with the fe80::/10 prefix, as defined in RFC 4291. These addresses are automatically assigned to every IPv6-enabled interface and are only valid on a single local link—they are never routed by routers, making them essential for neighbor discovery and local subnet communication. On the CompTIA Network+ N10-009 exam, this concept tests your ability to distinguish link-local addresses from global unicast or unique local addresses; a common trap is confusing fe80::/10 with the site-local fec0::/10 (now deprecated). Remember that link-local addresses are self-assigned and start with “fe80,” so think “fe80 = local link only.” A helpful memory tip: “fe80” sounds like “for eighty,” but just recall that any address beginning with “fe8” is link-local and never leaves the subnet.
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.
Which of the following IPv6 addresses is a link-local address?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
fe80::1
Option B (fe80::1) is correct because IPv6 link-local addresses always begin with the prefix fe80::/10, as defined in RFC 4291. These addresses are automatically assigned to every IPv6-enabled interface and are only valid on a single link (subnet), never routed. The address fe80::1 is a common example of a link-local address.
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.
✗
2001:db8::1
Why it's wrong here
2001:db8::1 is within the documentation prefix (2001:db8::/32) and is a global unicast address, not link-local.
✓
fe80::1
Why this is correct
Addresses starting with fe80: are link-local and are used for communication on the same link (e.g., Neighbor Discovery).
Related concept
Read the scenario before looking for a memorised answer.
✗
ff02::1
Why it's wrong here
ff02::1 is a well-known multicast address for all nodes on a local link, but it is a multicast address, not a unicast link-local address.
✗
2000::/3
Why it's wrong here
2000::/3 is the prefix for global unicast addresses, not a specific address. It does not represent a link-local address.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the distinction between the link-local prefix (fe80::/10) and the multicast prefix (ff00::/8), so candidates may confuse ff02::1 (all-nodes multicast) with a link-local unicast address.
Detailed technical explanation
How to think about this question
Link-local addresses are derived from the interface's MAC address using EUI-64 format or randomly generated (RFC 7217) for privacy. They are essential for Neighbor Discovery Protocol (NDP) operations, such as Duplicate Address Detection (DAD) and Router Solicitation, and are automatically assigned even if no global or unique local address is configured. In real-world scenarios, link-local addresses are used for routing protocol adjacencies (e.g., OSPFv3) and for accessing the link-local address of a router's default gateway.
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.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this N10-009 question in full detail.
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: fe80::1 — Option B (fe80::1) is correct because IPv6 link-local addresses always begin with the prefix fe80::/10, as defined in RFC 4291. These addresses are automatically assigned to every IPv6-enabled interface and are only valid on a single link (subnet), never routed. The address fe80::1 is a common example of a link-local address.
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.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
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These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. Which of the following IPv6 addresses is a valid link-local address?
easy
✓ A.fe80::1
B.2001:db8::1
C.ff02::1
D.10.0.0.1
Why A: Option A is correct because link-local addresses in IPv6 always start with the prefix fe80::/10, and fe80::1 is a valid example. These addresses are automatically configured on interfaces for local link communication and are not routable beyond the local network segment.
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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
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