[Dnsmasq-discuss] Getting dnsmasq to serve fqdns as the hostname

Alex Kiernan alex.kiernan at gmail.com
Wed Oct 15 13:04:03 BST 2008

On Tue, Oct 14, 2008 at 3:07 PM, Simon Kelley <simon at thekelleys.org.uk> wrote:
> Alex Kiernan wrote:
>> On Tue, Oct 14, 2008 at 1:58 PM, Simon Kelley <simon at thekelleys.org.uk>
>> wrote:
>>> Alex Kiernan wrote:
>>>> I'm trying to use dnsmasq to serve DHCP/DNS for a Solaris network
>>>> install server (jumpstart). It works perfectly and the DNS/DHCP
>>>> integration means that lots of the traditional problems go away (the
>>>> problem is that the Solaris installation procedure won't setup DNS as
>>>> the name service unless you already have DNS for the machine you're
>>>> building in place).
>>>> dnsmasq works absolutely perfectly for this, with one minor problem -
>>>> I need to serve an FQDN in the hostname option; if I feed this to
>>>> dnsmasq in a dhcp-host then unless my domain setting matches it
>>>> rejects it, and even then it strips it to the basename. If instead I
>>>> force through an option 12, whilst it serves the FQDN, it doesn't
>>>> update the DNS so the DNS checks fail later in the install.
>>>> At the moment I'm working around it by removing the section of code
>>>> from check_dhcp_hosts which enforces the domain/fqdn
>>>> matching/stripping behaviour, but is there another way? Or another way
>>>> which I could implement which is cleaner?
>>> If you explicitly send the FQDN as option 12, set the basename (using
>>> dhcp-host) _and_ set the domain in dnsmasq to the correct value, I think
>>> that will do what you want assuming I've understood correctly that you
>>> want
>>> to
>>> 1) Send the FQDN as option 12
>>> 2) have the FQDN resolve in DNS to the IP address allocated.
>> Yeah, I should have mentioned that combo - it does exactly what I
>> need, but only for one domain, whereas I need it to work for many
>> domains (as I want this box to act as a jumpstart server across many
>> different hosts). If domain could be scoped with a tag that'd do what
>> I need (or even just support multiple maybe?)
> That (domain scoped with a tag) is a long-standing feature request which is
> impossible to do in a backwards compatible way. See this list passim for the
> gory details.
> HOWEVER, the next best thing (domain based on subnet or IP address range) is
> available at the bleeding edge. Try
> http://thekelleys.org.uk/dnsmasq/test-releases/dnsmasq-2.46test15.tar.gz

Thanks - I've had a play and it doesn't really do what I want as
whilst I have some networks which have one domain on a subnet, we have
others where we end up with a bunch of machines in differing domains.

Is there a good way to go about adding FQDN hostname functionality[1]?
If I could just add that one feature it'd do exactly what I need (when
coupled with the dhcp-fqdn option).

[1] which I'm happy to do and send you the diffs.

Alex Kiernan

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