CCNA Network Infrastructure and Connectivity Practice Question
Which TWO statements are true about IPv6 link-local addresses?
⚠ Common exam trap
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.
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.
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.
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.
- ✗
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
IPv6 link-local addresses are precisely identified by the prefix fe80::/10. This specific 10-bit prefix range, spanning from fe80:: to febf::, is reserved exclusively for addresses that facilitate communication solely on the local network segment. This fundamental addressing convention ensures that these addresses are non-routable beyond their immediate link, directly satisfying the question's requirement to identify a true statement regarding the characteristics of IPv6 link-local addresses.
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?”
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Related to this question
Learn chapter
IPv4 Addressing and Address Classes
Key term
Interface
An interface is a point of connection or interaction between two systems, devices, or software components that allows them to exchange information or signals.
Key term
Stateless Address Autoconfiguration
Stateless Address Autoconfiguration (SLAAC) is a method that allows a device on an IPv6 network to automatically generate its own IP address without needing a dedicated server to assign one.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.