[Dnsmasq-discuss] IPv6 DNS name registration?

Simon Kelley simon at thekelleys.org.uk
Wed Jun 20 11:42:28 BST 2012

On 20/06/12 10:29, Chris O'Shea wrote:
> Good Morning All,
> I am currently running dnsmasq 2.62 with the following options set in
> the configuration file:
> domain-needed
> no-resolv
> local=/me.com/
> domain=me.com
> no-dhcp-interface=eth0
> no-dhcp-interface=eth2
> expand-hosts
> dhcp-range=fd00:ead5:c0a8:103::100,fd00:ead5:c0a8:103::200
> dhcp-option=option6:dns-server,[::]
> log-queries
> log-dhcp
> this quite happily configures IPv6 and the DNS server on the client machine,
> but I am currently working on getting the client to register its
> hostname with dnsmasq so that I can "ping6 <hostname>" from an
> alternate machine.  All clients send the IPv6 lookup through the
> dnsmasq machine, but because nothing has been registered it obviously
> can't resolve anything.
> I would be grateful if anyone could offer an insight into any missing
> options from the list above that could be causing this lack of
> registration when using an IPv6 only system?
> I would also be grateful to anyone who could advise how they have
> their IPv6-only network setup and functioning with DNS name registration.
> Best Regards,
> Chris.
> _______________________________________________
> Dnsmasq-discuss mailing list
> Dnsmasq-discuss at lists.thekelleys.org.uk
> http://lists.thekelleys.org.uk/mailman/listinfo/dnsmasq-discuss

You have to configure the DHCPv6 _client_ to send the hostname of the
machine it's configuring. You don't say what the clients are but
assuming they're Un*x boxes running dhclient, the magic in
/etc/dhcp/dhclient.conf looks like

send fqdn.fqdn "myhost.me.com";

The other way this is done is to configure dnsmasq with something like

dhcp-host=<mac address>,myhost.me.com

Sadly, on DHCPv6 this is much more difficult. You can't use the MAC
address to identify the host: you have to use the DUID. The DUID
contains the MAC address, but it has a load of other stuff too, which
makes it much more difficult to harvest.

There is some standards activity to define a DHCP option which provides
the MAC address, but it's not complete yet. An interesting example of
how the state-of-the-art has progressed in IPv4 since IPv6 was created,
leaving IPv6 paradoxically out-of-date.



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