Re: [squid-users] Force A lookup first, then AAAA

On 7/01/2012 3:56 a.m., Amos Jeffries wrote:
> On 6/01/2012 1:53 a.m., John wrote:
>> Basically I'm looking for a third option to "dns_v4_fallback", like
>> this:
>>
>> "If this is Squid will lookup A and only try AAAA if none found."
>>
>> John
>
> The way the DNS is written it is serial lookups, and to reverse the
> lookups you would need to rewrite the whole lookup and result merging
> sequence.
> We talk occasionally about making the DNS lookus asyn and using the
> first response immediately, but nobody has yet had time to write that
> code. Patches welcome.
>
> You should be able to reduce dns_timeout to a few seconds safely. The
> iteration is not through all remote DNS servers, but throughthe set of
> your own internal ones. A small set is recommended when facing this
> problem.
>
> Amos

In a brilliant piece of timing Henrik has returned from other work with
a patch which does the DNS system re-write to solve your problem. :-)
You can find it in squid-dev under the title "[MERGE] Send DNS A and
AAAA queries in parallel".
Current version will still wait the timeout of the longest response, but
not add the lag together for a huge total.

Amos
Received on Sat Jan 07 2012 - 01:59:03 MST