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200-901 Practice Question: An IPv6-enabled host is trying to discover the…

An IPv6-enabled host is trying to discover the MAC address of another host on the same link. The host knows the destination IPv6 address but does not have a corresponding entry in the neighbor cache. Which protocol and message type does the host use?

⚠ Common exam trap

Cisco often tests the distinction between the solicitation (type 135) and advertisement (type 136) messages, and the trap here is that candidates may confuse Neighbor Solicitation with Router Solicitation or mistakenly think ARP is used in IPv6.

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

Neighbor Solicitation (ICMPv6 type 135)

When an IPv6 host needs to resolve a known destination IPv6 address to its MAC address on the same link, it sends a Neighbor Solicitation (NS) message, which is ICMPv6 type 135. This message is multicast to the solicited-node multicast address of the target, and the host with that IPv6 address responds with a Neighbor Advertisement (ICMPv6 type 136) containing its MAC address. This process replaces ARP in IPv4 and is defined in RFC 4861.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

  • Neighbor Advertisement (ICMPv6 type 136)

    Why it's wrong here

    NA is the reply, not the request.

  • Router Solicitation (ICMPv6 type 133)

    Why it's wrong here

    RS is for router discovery.

  • Neighbor Solicitation (ICMPv6 type 135)

    Why this is correct

    NS is used for address resolution.

  • Address Resolution Protocol (ARP)

    Why it's wrong here

    IPv6 does not use ARP.

Visual reference

Client Recursive Resolver Root DNS (13 root servers) TLD DNS (.com, .org, …) Authoritative example.com query IP addr answer

Quick reference

Access Control Model Comparison

ModelAcronymWho Controls Access?Best For
Discretionary Access ControlDACResource ownerSmall teams, file shares
Mandatory Access ControlMACSystem / security labelsClassified govt / military
Role-Based Access ControlRBACAdministrator (via roles)Enterprise environments
Attribute-Based Access ControlABACPolicy engine (user + resource attributes)Fine-grained, dynamic policies
Rule-Based Access ControlRuBACSystem rules / ACLsFirewall rules, network ACLs

About these practice questions

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JA

Written by Johnson Ajibi, MSc IT Security

Senior Network & Security Engineer · founder of Courseiva

This 200-901 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 200-901 exam.