Amos,
This is a great info about how squid handles DNSes.
I used to get confused when in some rare cases squid log was showing IPv6 addresses.
This e-mail clears it all. Also good note about timeouts used.
I think you must add the content of your reply at:
Features/IPv6 - http://wiki.squid-cache.org/Features/IPv6
As that is the first place people try to find issues related to IPv4/IPv6.
OR put a link to this e-mail in above article:
Link - http://marc.info/?l=squid-users&m=135597043111104&w=2
(could not find e-mail at squid-cache mail archives [will happen tonight I suppose])
Thanks and regards,
Amm.
----- Original Message -----
> From: Amos Jeffries <squid3@treenet.co.nz>
> To: squid-users@squid-cache.org
> Cc:
> Sent: Thursday, 20 December 2012 7:56 AM
> Subject: Re: [squid-users] Squid 3.2.5 wants to use IPv6 address?
>
>
> For the record squid-3.2 tries all the destination IPs it can find, the above
> method only means that all attempts failed and the given IPv6 address was the
> *latest* tried. Squid could very well have tried a bunch of IPv4 addresses
> earlier which failed, or scheduled them for connecting to later but
> forward_timeout and connect_timeout prevented reaching them.
>
> Also, Squid by default only tries to connect 10 times then gives up. Lookign at
> teh website address list I notice that it on a primarily IPv6 network.
>
> # host www.vkontakte.ru
> www.vkontakte.ru has IPv6 address 2a00:bdc0:3:103:1:0:403:908
> www.vkontakte.ru has IPv6 address 2a00:bdc0:3:103:1:0:403:909
> www.vkontakte.ru has IPv6 address 2a00:bdc0:3:103:1:0:403:900
> www.vkontakte.ru has IPv6 address 2a00:bdc0:3:103:1:0:403:901
> www.vkontakte.ru has IPv6 address 2a00:bdc0:3:103:1:0:403:902
> www.vkontakte.ru has IPv6 address 2a00:bdc0:3:103:1:0:403:903
> www.vkontakte.ru has IPv6 address 2a00:bdc0:3:103:1:0:403:904
> www.vkontakte.ru has IPv6 address 2a00:bdc0:3:103:1:0:403:905
> www.vkontakte.ru has IPv6 address 2a00:bdc0:3:103:1:0:403:906
> www.vkontakte.ru has IPv6 address 2a00:bdc0:3:103:1:0:403:907
> www.vkontakte.ru has address 87.240.188.252
> www.vkontakte.ru has address 87.240.188.254
>
>
> Squid will do all 10 connection attemps before reaching any of the IPv4
> addresses.
>
> You can use the dns_v4_first sort order option, or you can extend the number of
> connection attempts Squid performs with forward_max_tries.
> http://www.squid-cache.org/Doc/config/forward_max_tries/
> http://www.squid-cache.org/Doc/config/dns_v4_first/
>
>
> Some other things to be aware of in 3.2:
> * connect_timeout controls each individual TCP connection setup, ensure this is
> small to avoid broken IPs quickly but long enough to use slow links.
> * forward_timeout controls *total* time locating a working connection. For
> example, N connection attempts with their connect_timeout on each one all fit
> within forward_timeout, but the N+1 attempt would take longer so is cut short or
> never tried.
>
> http://www.squid-cache.org/Doc/config/connect_timeout/
> http://www.squid-cache.org/Doc/config/forward_timeout/
Received on Thu Dec 20 2012 - 04:48:15 MST
This archive was generated by hypermail 2.2.0 : Thu Dec 20 2012 - 12:00:05 MST