Question 45 of 1,819
Network Infrastructure and ConnectivitymediumMultiple SelectObjective-mapped

Quick Answer

The answer is that IPv6 link-local addresses are automatically configured on all IPv6-enabled interfaces. This automatic generation occurs through Stateless Address Autoconfiguration (SLAAC) as defined in RFC 4862, using the fe80::/10 prefix, which ensures every interface can immediately participate in neighbor discovery and other link-local operations without needing a DHCPv6 server or manual intervention. On the CCNA 200-301 v2 exam, this concept tests your understanding of IPv6 fundamentals and the critical role link-local addresses play in routing protocols like OSPFv3 and in the Neighbor Discovery Protocol. A common trap is confusing link-local with global unicast addresses—remember that link-local addresses are never routable off the local link and are mandatory for all IPv6 interfaces. For a quick memory tip, think of the fe80 prefix as "For Every 8-0 interface," reinforcing that every IPv6-enabled interface automatically gets one.

CCNA Network Infrastructure and Connectivity Practice Question

This 200-301 practice question tests your understanding of network infrastructure and connectivity. 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.

Which TWO statements are true about IPv6 link-local addresses?

Question 1mediummulti select
Study the full IPv6 explanation →

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

They are automatically configured on all IPv6-enabled interfaces.

Option A is correct because IPv6 link-local addresses (fe80::/10) are automatically generated on every IPv6-enabled interface using Stateless Address Autoconfiguration (SLAAC) as defined in RFC 4862. This ensures that each interface has a unique local address for neighbor discovery and other link-local operations without requiring manual configuration or a DHCPv6 server.

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.

  • They are automatically configured on all IPv6-enabled interfaces.

    Why this is correct

    IPv6-enabled interfaces automatically generate a link-local address, even if no other IPv6 address is configured.

    Related concept

    Read the scenario before looking for a memorised answer.

  • They are routable across the entire IPv6 internet.

    Why it's wrong here

    Link-local addresses are not routable; they are confined to a single link or network segment.

  • They always use the EUI-64 format for the interface ID.

    Why it's wrong here

    While EUI-64 is one method, link-local addresses can also be randomly generated (privacy extensions) or manually configured.

  • They are used as the default gateway address for IPv6 hosts.

    Why it's wrong here

    The default gateway is typically a global or unique local address, not a link-local address, because the host needs to send packets off the local link.

  • They are identified by the prefix fe80::/10.

    Why this is correct

    All IPv6 link-local addresses begin with fe80::/10, though typically written as fe80::/64 in practice.

    Related concept

    Read the scenario before looking for a memorised answer.

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 200-301 exam frequently reuses these exact scenarios with slightly different constraints.

They are automatically configured on all IPv6-enabled interfaces.Correct answer

Why this is correct

IPv6-enabled interfaces automatically generate a link-local address, even if no other IPv6 address is configured.

They are routable across the entire IPv6 internet.Wrong answer — click to see why

Why this is wrong here

Link-local addresses are not routable; they are confined to a single link or network segment. Routers will not forward packets with a link-local source or destination address beyond the local subnet.

Why candidates choose this

Students may confuse link-local addresses with global unicast addresses, assuming all IPv6 addresses are routable. The 'link-local' term might be misinterpreted as 'local to the network' rather than 'local to the link'.

They always use the EUI-64 format for the interface ID.Wrong answer — click to see why

Why this is wrong here

While EUI-64 is one method for generating the interface ID, link-local addresses can also use randomly generated identifiers (privacy extensions) or be manually configured. The statement that they always use EUI-64 is incorrect.

Why candidates choose this

Many textbooks emphasize EUI-64 as the standard method for IPv6 address generation, leading students to believe it is mandatory for link-local addresses. They may overlook the existence of privacy extensions or manual configuration.

They are used as the default gateway address for IPv6 hosts.Wrong answer — click to see why

Why this is wrong here

The default gateway for IPv6 hosts is typically a global unicast or unique local address, not a link-local address. While routers may send Router Advertisements with a link-local source, the default gateway address learned by hosts is the router's link-local address, but the host uses that link-local address as the next-hop, not as the default gateway address itself. The statement is misleading because the default gateway is often the link-local address of the router, but the host uses it as the next-hop, not as a routable address.

Why candidates choose this

Students may recall that IPv6 hosts learn the default gateway from Router Advertisements, which use link-local addresses. They might incorrectly assume that the default gateway address itself is a link-local address, but in practice, the host uses the link-local address as the next-hop for off-link traffic.

Analysis generated from the official 200-301blueprint 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

Cisco often tests the misconception that link-local addresses are routable or that they always use EUI-64, when in fact they are strictly link-scoped and can use privacy extensions to randomize the interface ID.

Detailed technical explanation

How to think about this question

Link-local addresses use the prefix fe80::/10 (first 10 bits), but the actual interface identifier is typically 64 bits long, making the full address fe80::/64. In real-world scenarios, if a router's link-local address changes (e.g., due to interface reset), all hosts on that link must re-learn the default gateway via new RAs, which can cause temporary connectivity loss. The 'ipv6 address autoconfig' command on Cisco IOS enables automatic link-local address generation using EUI-64 or random identifiers.

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.

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.

Related practice questions

Related 200-301 practice-question pages

Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.

Practice this exam

Start a free 200-301 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 200-301 question test?

Network Infrastructure and Connectivity — This question tests Network Infrastructure and Connectivity — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: They are automatically configured on all IPv6-enabled interfaces. — Option A is correct because IPv6 link-local addresses (fe80::/10) are automatically generated on every IPv6-enabled interface using Stateless Address Autoconfiguration (SLAAC) as defined in RFC 4862. This ensures that each interface has a unique local address for neighbor discovery and other link-local operations without requiring manual configuration or a DHCPv6 server.

What should I do if I get this 200-301 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

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 →

How Courseiva writes practice questions · Editorial policy

Keep practising

More 200-301 practice questions

Last reviewed: Jun 11, 2026

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.

Loading comments…

Sign in to join the discussion.

This 200-301 practice question is part of Courseiva's free Cisco 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 200-301 exam.