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BeginnerPublished 2026-08-12

CCNA Foundations: SLAAC — Let the Router Hand Out the Prefix

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Single-site IPv4/IPv6 lab where IPv4 is already working. You will enable IPv6 routing on the router and place a single /64 on the user LAN so two hosts autoconfigure via SLAAC. Then verify each host’s chosen IPv6 address and the learned default route via the router’s link-local address, and test end-to-end IPv6 connectivity.

Track
Est. time
45 minutes
Difficulty
Beginner
Topics

Learning objectives

  • Enable IPv6 unicast routing on a Cisco IOS router so it originates Router Advertisements (RAs)
  • Configure a /64 IPv6 prefix on a host-facing LAN interface to support SLAAC
  • Confirm host-side autoconfiguration: global address within the advertised /64 and a default route via the router’s link-local
  • Verify IPv6 connectivity host-to-host and host-to-router, and inspect neighbor/route/RA state on both router and hosts

Troubleshooting focus

  • If hosts do not get a global IPv6 address, ensure ipv6 unicast-routing is enabled on the router. Without it, no RAs are sent.
  • If hosts get only link-local addresses, confirm the LAN interface has exactly a /64 (SLAAC requires /64).
  • If default route is missing on hosts, check that RAs are not suppressed on the router LAN interface and the interface is up/up.
  • If you see duplicate address detection failures, check for another RA source or an overlapping prefix on the segment.
  • If IPv4 works but IPv6 pings fail, verify the router’s LAN IPv6 address and prefix are correct and hosts learned a default via fe80::/10.

Topology

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Grade your work

How this lab is graded
  • Build it your way. Where a lab lets you choose a value — a VLAN name, an interface description — grading checks that you configured it, not which name you picked. Names that another line has to reference, like an ACL applied with access-class, are stated in the guide and do have to match.
  • Addresses, modes and protocol keywords are exact. An IP address, a subnet mask, switchport mode trunk, an encapsulation — these carry the meaning of the lab, so they are graded as written in the guide.
  • Grading reads your saved configuration. Export the lab from CML after you have configured it, and make sure anything you set is in the running-config — a change that only exists in a terminal session never reaches the grader.
  • You can submit as many times as you like. Your best score stands, and each attempt tells you which checks passed so you can work the gaps.
  • Scored something you believe is correct? Use Report an issue on this page — that is exactly how the grading fixes in the changelog got found.

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