Re: [squid3-ipv6] dns_internal.cc

From: Amos Jeffries <squid3@dont-contact.us>
Date: Tue, 27 Nov 2007 10:39:25 +1300 (NZDT)

>>
>> > imasd.ipv6.elmundo.es will fire an error, even with n=4 ...
>>
>> which error ?
>>
>
> (debug_options 78,9 )
>
>
> 2007/11/26 15:48:37.010| idnsALookup: buf is 39 bytes for
> imasd.ipv6.elmundo.es, id = 0xa80c
> 2007/11/26 15:48:37.010| idnsRead: starting with FD 7
> 2007/11/26 15:48:37.021| idnsRead: FD 7: received 325 bytes from
> 62.42.230.24:53
> 2007/11/26 15:48:37.021| idnsGrokReply: ID 0xa80c, 4 answers
> ==========================================================================
> 2007/11/26 15:48:37.021| idnsGrokReply: imasd.ipv6.elmundo.es AAAA query
> failed. Trying A now instead.
>

Ahh. You are sort of right. Its performing the right behaviour, just the
wrong debug being shown. Should have said 'configured to also try A'.
Fixed that.

<snip>
>>
> Right. But the above log error is invoked with state:
>
> q->need_A = 1 , Config.onoff.dns_require_A == 1 , n = 4
>
> evaluating the "if" guard to true. And the message is
>
> "idnsGrokReply: imasd.ipv6.elmundo.es AAAA query failed"
>
>
>
>> >
>> > Even with that, ipcache.cc seems to have problems with canonical
>> > names...
>>
>> Any more detail on what those problems are?
>> I have seen some weird behaviour listing ipcache, but nothing I have
>> been able to track down yet. If you can provide any light all the
>> better. My bug has something to do with walking the hash list under some
>> still unknown conditions.
>>
>
> Yes, it's about that, (a flag?) When I get a deeper knowledge I'll
> write..
> Meanwhile, if you locally modify the || by && (just to test, perhaps
> this is not the rigth solution, up to you) , you can reproduce the
> failure by entering a non-canonical name, i.e. www.google.com ,
> www.ipv6.elmundo.es , (no matter if IPv4 or IPv6) . By contrast,
> www.l.goggle.com and imasd.ipv6.elmundo.es, canonical names, seem to be
> answered...
>

The lookup behaviour can be overridden with the squid.conf option
"dns_v4_fallback off".

I'll get onto it when I have these pinger malformed packets dead.

Amos
Received on Mon Nov 26 2007 - 14:39:28 MST

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