Comment 51 for bug 1003842

On 04/02/13 15:36, Sergio Callegari wrote:
> On 04/02/2013 15:40, Simon Kelley wrote:
>> On 03/02/13 07:48, Thomas Hood wrote:
>>>> there's still the unresolved question
>>>> of whether re-enabling --strict-order
>>>> will suffice as a workaround, since
>>>> 12.10 relies on DBus to populate the
>>>> nameservers. Is there any extra
>>>> information on this?
>>> Please try it and report back. :-)
>>>
>>> (Put "strict-order" in a file in /etc/NetworkManager/dnsmasq.d/; stop
>>> network-manager; make sure all dnsmasq processes are dead; start
>>> network-manager.)
>>>
>> It doesn't work: It will always use the same server first, but the order
>> of servers given to the DBus interface isn't preserved internally, and
>> actually changes each time the DBus interface is used.
>>
>>
>> Cheers,
>>
>> Simon.
> Isn't it possible to change dnsmasq behavior to query the servers in any order
> or in parallel and in the case the first server to reply says "I don't know"
> avoid relying on that information, rather wait and see if in a reasonable time
> some other server answers "I do"?

You're far from the first person to ask that question. The answer is
that there is no possible response in the DNS protocol which means "I
don't know". NXDOMAIN or NODATA answers _don't_ mean that; they mean "I
know that this domain doesn't exist". They also make up quite a large
proportion of the DNS results returned to the average host, so that all
of those queries would suddenly take much longer.

>
> With the current behavior, whenever I need to access a captive portal, I
> basically have to press the "reload page" button 50 times until for some reasons
> the order in which the nameservers reply becomes the good one.

The fundamental problem lies with the captive portal, and no good
solution which can be implemented by dnsmasq has so far been devised.

Cheers,

Simon.