Question 1mediummultiple choice
Full question →mediummultiple choiceObjective-mapped
Which statement best describes an IPv6 link-local address?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Best answer
It is used only on the local link and is not routed beyond that segment.
This is correct because link-local addresses have local-link scope only.
B
Distractor review
It is the public IPv6 address used for Internet reachability.
This is wrong because public global reachability uses global unicast addresses, not link-local addresses.
C
Distractor review
It is used only when DHCPv6 fails.
This is wrong because link-local addressing is normal IPv6 behavior, not a fallback error condition.
D
Distractor review
It replaces the need for a default gateway.
This is wrong because hosts still need next-hop routing information for off-link traffic.
Common exam trap
Common exam trap: answer the scenario, not the keyword
A frequent exam trap is to assume that IPv6 link-local addresses function like global unicast addresses and can be routed beyond the local network segment. Candidates may mistakenly believe that link-local addresses provide Internet reachability or replace the need for a default gateway. This confusion arises because link-local addresses are automatically assigned and always present, which might suggest they have broader use. However, link-local addresses are strictly limited to local-link communication and cannot traverse routers. Misunderstanding this scope leads to incorrect routing assumptions and flawed network designs.
Technical deep dive
How to think about this question
IPv6 link-local addresses are special IP addresses automatically configured on all IPv6-enabled interfaces. They always begin with the prefix FE80::/10 and are used exclusively for communication within the local network segment or link. These addresses are essential for basic IPv6 operations such as neighbor discovery, router advertisements, and local communication before global or unique local addresses are assigned. Unlike global unicast addresses, link-local addresses are not routable beyond the local link, ensuring that traffic using these addresses remains confined to the immediate network segment. In Cisco networking and the CCNA context, link-local addresses play a critical role in routing protocols and network functions. Routers use link-local addresses to establish neighbor adjacencies in protocols like OSPFv3 and EIGRP for IPv6. Hosts typically use the router’s link-local address as the next-hop address for off-link traffic, even when global addresses are assigned. This behavior ensures that routing decisions and packet forwarding within the local link are efficient and standardized, supporting IPv6’s design principles. A common exam trap is to confuse link-local addresses with global or public IPv6 addresses, assuming they can be routed across the Internet or between different network segments. This misunderstanding leads to incorrect assumptions about address scope and routing behavior. Practically, link-local addresses are vital for local communication and routing protocol operations but cannot replace global addressing or default gateways. Recognizing their local scope and purpose helps avoid misconfigurations and supports proper IPv6 network design.
KKey Concepts to Remember
- IPv6 link-local addresses always use the FE80::/10 prefix and are automatically assigned to all IPv6-enabled interfaces.
- Link-local addresses are used exclusively for communication within the local network segment and are not routable beyond that link.
- Routers use link-local addresses to establish neighbor relationships and exchange routing protocol information such as OSPFv3 adjacencies.
- Hosts use the router’s link-local address as the next-hop address for off-link traffic even when global IPv6 addresses are configured.
- Link-local addressing is a fundamental IPv6 behavior and not a fallback mechanism like DHCPv6 failure handling.
- Link-local addresses cannot replace the need for a default gateway because they do not provide routing beyond the local link.
- Confusing link-local addresses with global unicast addresses leads to incorrect assumptions about IPv6 routing and reachability.
- IPv6 link-local addresses enable essential local-link functions such as neighbor discovery, router advertisements, and local communication.
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.
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More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
Question 1
A router learns the same prefix from both OSPF and EIGRP. Which route is installed by default?
Question 2
A router shows this output: R1#show ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface 10.1.1.2 1 FULL/DR 00:00:34 192.168.12.2 GigabitEthernet0/0 10.1.1.3 1 2WAY/DROTHER 00:00:39 192.168.12.3 GigabitEthernet0/0 Which statement is correct?
Question 3
What is the OSPF metric called?
Question 4
A non-root switch has two uplinks toward the root bridge. One path has a lower total STP cost than the other. What role will the lower-cost uplink have?
Question 5
A router interface applies this ACL inbound: 10 deny tcp any any eq 80 20 permit ip any any A user reports that web browsing to a server by IP address fails, but ping works. Which statement best explains the behavior?
Question 6
A router learns route 198.51.100.0/24 from OSPF with AD 110 and also has a static route to the same prefix configured with AD 150. Which route is installed?
FAQ
Questions learners often ask
What does this 200-301 question test?
IPv6 link-local addresses always use the FE80::/10 prefix and are automatically assigned to all IPv6-enabled interfaces.
What is the correct answer to this question?
The correct answer is: It is used only on the local link and is not routed beyond that segment. — An IPv6 link-local address is used only on the local Layer 2 segment and is not routed beyond that link. In practical terms, it lets devices communicate with nearby neighbors even before or without having a globally routable IPv6 address. Routers use link-local addresses heavily for neighbor relationships, and hosts often use the router’s link-local address as the next hop for off-link traffic. This is a foundational IPv6 concept. The common trap is to treat link-local addresses like normal Internet-routable addresses. They are not. They are essential, but they are local-scope only.
What should I do if I get this 200-301 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
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