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IntermediatePublished 2026-08-19

CCNA Foundations: DHCPv6 Relay — Server Is Elsewhere

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Deploy a stateless DHCPv6 service on a remote router and relay client Information-Requests from a branch LAN across a routed core to that server. IPv4 is already fully functional; your job is to build the IPv6 DHCPv6 relay path and confirm clients receive DNS/domain options while keeping IPv6 addressing via SLAAC.

Track
Est. time
60 minutes
Difficulty
Intermediate
Topics

Learning objectives

  • Configure a stateless DHCPv6 pool with DNS and domain options on a server-side router.
  • Bind an IPv6 DHCPv6 server pool to the correct listening interface.
  • Relay DHCPv6 Information-Requests from a client LAN to a remote server.
  • Advertise the IPv6 Other Configuration flag so hosts request DHCPv6 options while retaining SLAAC addressing.
  • Verify and troubleshoot DHCPv6 relay using router show commands and host-side tests.

Troubleshooting focus

  • Clients do not receive DNS/domain via DHCPv6 while IPv6 pings work: verify the Other Configuration flag is set on the branch LAN interface.
  • No DHCPv6 packets reach the server: ensure the relay destination is applied on the client-facing LAN interface, not the transit interface.
  • Server not answering: confirm the BRANCH10-INFO pool exists, carries its dns-server and domain-name options, and is bound to RTR-DC Ethernet0/0.
  • Routing asymmetry: check IPv6 static routes on CORE toward the branch LAN and defaults on BRANCH/DC.
  • Host-side: if resolv.conf doesn’t populate, run a DHCPv6 client (e.g., dhclient -6 -S eth0) after relay is configured.

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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