easyMultiple Choice
300-410 Practice Question: Which RFC defines the IPv6 Neighbor Discovery…
Which RFC defines the IPv6 Neighbor Discovery Protocol that is the basis for many First Hop Security features?
⚠ Common exam trap
Cisco often tests the distinction between the RFC that defines the protocol itself (RFC 4861 for NDP) versus RFCs that define supporting technologies like ICMPv6 (RFC 4443) or addressing (RFC 4291), leading candidates to confuse the foundational RFC with related but separate standards.
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
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RFC 4861
RFC 4861 defines the IPv6 Neighbor Discovery Protocol (NDP), which is the foundation for IPv6 First Hop Security (FHS) features. NDP replaces ARP in IPv6 and provides address resolution, router discovery, neighbor unreachability detection, and redirect functions, all of which are leveraged by FHS mechanisms like RA Guard, DHCPv6 Guard, and Source Address Validation Improvement (SAVI).
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
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RFC 4861
Why this is correct
RFC 4861 specifies IPv6 Neighbor Discovery, defining router solicitation, router advertisement, neighbour solicitation and neighbour advertisement messages. First Hop Security features such as RA Guard and IPv6 snooping build directly on these message types and their processing rules.
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RFC 2460
Why it's wrong here
RFC 2460 specifies IPv6 itself, defining the header format and extension header mechanism, not Neighbor Discovery. It is tempting because Neighbor Discovery messages are carried inside IPv6 packets, so the base protocol specification appears related, yet the Router Solicitation, Advertisement, Neighbor Solicitation and Advertisement procedures are defined elsewhere.
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RFC 4291
Why it's wrong here
RFC 4291 defines IPv6 addressing architecture, including address types and formats, not Neighbor Discovery. It is tempting because Neighbor Discovery operates on link-local and solicited-node multicast addresses specified there, but the protocol's message formats and host/router procedures are defined in a separate RFC.
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RFC 4443
Why it's wrong here
RFC 4443 defines ICMPv6, the message transport used by Neighbor Discovery, not Neighbor Discovery itself. It is tempting because Neighbor Solicitation and Advertisement are ICMPv6 message types, so the RFC appears relevant, yet it specifies error and informational message formats rather than the neighbour resolution and reachability procedures.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 300-410 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 300-410 exam.