The answer is the link-local address, which is automatically assigned to an IPv6 interface upon initialization without any server or configuration protocol. This happens because the node uses Stateless Address Autoconfiguration (SLAAC) to generate an address from the fe80::/10 prefix, typically combining it with its interface identifier based on the MAC address. This automatic assignment is mandatory for Neighbor Discovery Protocol (NDP) and enables essential link-local communication, allowing the node to function on the local segment immediately. On the CompTIA Network+ N10-009 exam, this concept tests your understanding of IPv6’s default behavior versus stateful addressing like DHCPv6; a common trap is confusing the link-local address with a global unicast address, which requires additional configuration. Remember the memory tip: “Link-local starts with FE80—no server, no worry.”
N10-009 Networking Concepts Practice Question
This N10-009 practice question tests your understanding of networking concepts. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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.
An engineer is configuring a network and needs to understand the default behavior of an IPv6 node. When an IPv6 interface is initialized, which type of address is automatically assigned without any configuration server?
Why wrong: Global unicast addresses are routable on the internet and require assignment from an address range or DHCPv6, they are not automatically generated without configuration.
B
Unique local address
Why wrong: Unique local addresses (fc00::/7) are analogous to IPv4 private addresses and require administrative assignment, not automatic generation on interface initialization.
C
Link-local address
Link-local addresses (fe80::/10) are automatically created when an IPv6 interface is enabled, using methods like EUI-64 or privacy extensions.
D
Multicast address
Why wrong: Multicast addresses (ff00::/8) are not assigned to interfaces as unicast addresses; they are used for group communication.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Link-local address
When an IPv6 interface is initialized, it automatically generates a link-local address (fe80::/10) using Stateless Address Autoconfiguration (SLAAC) without requiring any external server (e.g., DHCPv6). This address is mandatory for neighbor discovery and other link-local communication, allowing the node to operate on the local network segment immediately.
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.
✗
Global unicast address
Why it's wrong here
Global unicast addresses are routable on the internet and require assignment from an address range or DHCPv6, they are not automatically generated without configuration.
✗
Unique local address
Why it's wrong here
Unique local addresses (fc00::/7) are analogous to IPv4 private addresses and require administrative assignment, not automatic generation on interface initialization.
✓
Link-local address
Why this is correct
Link-local addresses (fe80::/10) are automatically created when an IPv6 interface is enabled, using methods like EUI-64 or privacy extensions.
Related concept
Read the scenario before looking for a memorised answer.
✗
Multicast address
Why it's wrong here
Multicast addresses (ff00::/8) are not assigned to interfaces as unicast addresses; they are used for group communication.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the misconception that a global unicast address is automatically assigned, but the trap here is that only the link-local address is generated by default, while global and unique local addresses require additional configuration or router presence.
Detailed technical explanation
How to think about this question
The link-local address is derived from the interface's MAC address using the EUI-64 format (or a randomly generated identifier per RFC 7217 for privacy), combined with the fe80::/10 prefix. This address is essential for Neighbor Discovery Protocol (NDP) operations such as Duplicate Address Detection (DAD) and router solicitation, and it remains active even if no global or unique local address is configured. In real-world scenarios, a misconfigured router advertisement can cause a node to fail to obtain a global address, but the link-local address always works for local troubleshooting (e.g., pinging fe80::1).
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 at a university connects two campus buildings via a fibre link. Both routers run OSPF, but no adjacency forms — even though both routers can ping each other. The engineer finds one router is in area 0 and the other in area 1. OSPF adjacency requires matching area numbers, hello/dead timers, and network type. IP reachability alone is not enough.
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: Link-local address — When an IPv6 interface is initialized, it automatically generates a link-local address (fe80::/10) using Stateless Address Autoconfiguration (SLAAC) without requiring any external server (e.g., DHCPv6). This address is mandatory for neighbor discovery and other link-local communication, allowing the node to operate on the local network segment immediately.
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.
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Question Discussion
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