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 <squ...@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/
