[Dnsmasq-discuss] Wildcard Subdomains: DNS/DHCP ??

[richardvoigt at gmail.com]

On Mon, Dec 13, 2010 at 5:55 AM, Simon Kelley <simon at thekelleys.org.uk> wrote:
> richardvoigt at gmail.com wrote:
>> Have you tried using the cname option?  I'm not sure if stock dnsmasq
>> allows wildcards during cname matching, but there's definitely a patch
>> to add it floating around here somewhere...
>
> OP: you can't do what you want with stock dnsmasq.
>
> Richard: are you sure about the patch? There's one to add regexp
> matching to --server and --address, but I'm not aware if one for
> wildcards for CNAMEs. It's a good idea though, to allow something like

Most likely that's the one I'm thinking of.

>
> cname=*.thekelleys.org.uk,server.thekelleys.org.uk
>
> That add the functionality without touching the huge mass of code that
> assumes a DHCP lease has exatclt one name associated with it.
>
> There would have to be some thought given to avoiding the problem where
> server.thekelleys.org.uk (in the above example) accidentally resolved to
> a CNAME of itself.

Is it a problem to return a reflexive CNAME record, as long as the A
record(s) is/are also returned?  Is a CNAME supposed to hide dynamic
information (dhcp lease) matching the same name?  That could be useful
for ISPs, because customers tend to type the damnedest things into
their TCP/IP and computer configuration (seeing the main website URL
entered into the computer name field, or static IP address
configuration with the DNS server IP address [or worse: gateway] typed
into the node IP address, are just two of the infinite combinations
possible with users who think they're more technical than they are).
But dhcp-ignore-names or domain already exist to prevent that misery
anyway.

Since it's possible to have an infinite loop involving multiple rules,
even without wildcards, I would suggest limiting each alias rule to
being matched only once per request.

>
> Simon.
>
>>
>> On Fri, Dec 10, 2010 at 6:12 PM, Andy Leak <andy at r210.com> wrote:
>>> Our work requires frequent creating / destroying of virtual machines,
>>> and the integrated DHCP/DNS of DNSMASQ is really useful.
>>>
>>> But I haven't been able to get DNSMASQ to resolve wildcard subdomains
>>> associated with each dynamic address.
>>>
>>> For example, the domains 'sub1.x' and 'sub2.x' should resolve to the
>>> same address as 'x'.
>>>
>>> From the documentation it looks like you can set up wildcard
>>> subdomains for static addresses.  (using
>>> address=/.machine.domain.info/10.0.0.24 in /etc/dnsmasq.conf)
>>>
>>> Is there a way to setup wildcard subdomains for dynamically generated
>>> addresses??
>>>
>>> thanks, Andy
>>>
>>> _______________________________________________
>>> Dnsmasq-discuss mailing list
>>> Dnsmasq-discuss at lists.thekelleys.org.uk
>>> http://lists.thekelleys.org.uk/mailman/listinfo/dnsmasq-discuss
>>>
>>
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>
>