[Bug 1092691] Re: A way to disable AAAA lookups in the resolver (again)

[Carlo Wood]

Same problem here... and now it's 2017. My ISP is not going to support
ipv6 for years :(, and in the mean time it would be nice if connections
to servers with both, ipv4 and ipv6 (like google) I wouldn't run into a
2 minute timeout all the time :/.

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to glibc in Ubuntu.
https://bugs.launchpad.net/bugs/1092691

Title:
  A way to disable AAAA lookups in the resolver (again)

Status in glibc package in Ubuntu:
  Confirmed

Bug description:
  I like to known what's the way to disable DNS AAAA queries.
  Already have disabled all resources ipv6.

  1. Changes in grub:
  vim /etc/default/grub
      GRUB_CMDLINE_LINUX_DEFAULT="ipv6.disable=1"
  update-grub

  2. I'm using 12.04 LTS version (builtin ipv6 support)
  grep -i ipv6 /boot/config-3.2.0-24-generic
      CONFIG_IPV6=y
      CONFIG_IPV6_PRIVACY=y
      ...

  Before this i try with sysctl, but tcp6 sockets still alive.
  After grub changes this solve the question - i can disable ipv6 address and networks sockets too.

  But, internal lookups stay wrong.
  Some sites like www.caixa.gov.br are slow.

  When i sniff my connection i can see many DNS AAAA records and server fail
  Running "lynx www.caixa.gov.br"

  15:57:11.332463 IP 127.0.0.1.58734 > 127.0.0.1.53: 63741+ AAAA? www.caixa.gov.br. (34)
  15:57:16.337439 IP 127.0.0.1.58734 > 127.0.0.1.53: 63741+ AAAA? www.caixa.gov.br. (34)
  15:57:21.342488 IP 127.0.0.1.58067 > 127.0.0.1.53: 1244+ AAAA? www.caixa.gov.br.localdomain. (46)
  15:57:21.342579 IP 127.0.0.1.53 > 127.0.0.1.58067: 1244 NXDomain 0/1/0 (121)
  15:57:21.342648 IP 127.0.0.1.51657 > 127.0.0.1.53: 3236+ A? www.caixa.gov.br. (34)
  15:57:21.342723 IP 127.0.0.1.53 > 127.0.0.1.51657: 3236 1/0/0 A 200.201.161.106 (50)
  15:57:21.353289 IP 127.0.0.1.58482 > 127.0.0.1.53: 15390+ AAAA? www.caixa.gov.br. (34)
  15:57:26.358326 IP 127.0.0.1.58482 > 127.0.0.1.53: 15390+ AAAA? www.caixa.gov.br. (34)
  15:57:31.363381 IP 127.0.0.1.48398 > 127.0.0.1.53: 21648+ AAAA? www.caixa.gov.br.localdomain. (46)
  15:57:31.363487 IP 127.0.0.1.53 > 127.0.0.1.48398: 21648 NXDomain 0/1/0 (121)
  15:57:31.363560 IP 127.0.0.1.55657 > 127.0.0.1.53: 49860+ A? www.caixa.gov.br. (34)
  15:57:31.363643 IP 127.0.0.1.53 > 127.0.0.1.55657: 49860 1/0/0 A 200.201.161.106 (50)
  15:57:31.364319 IP 127.0.0.1.55431 > 127.0.0.1.53: 38110+ AAAA? www.caixa.gov.br. (34)
  15:57:36.369352 IP 127.0.0.1.55431 > 127.0.0.1.53: 38110+ AAAA? www.caixa.gov.br. (34)

  I do bind changes too
  vim /etc/default/bind9
      RESOLVCONF=no
      OPTIONS="-4 -u bind"

  vim /etc/bind/named.conf.options
          forward only;
          forwarders {
                  208.67.222.222;
                  8.8.8.8;
          };

  This dont solve AAAA requests.
  I like to known a way to prefer ipv4 queries (A) or disable ipv6 queries.

  When i'm using squid proxy the same problem occur.
  To solve this i need compile squid with --disable-ipv6.
  This works to Squid proxy, but i think that the best way is disable all DNS AAAA queries.

  This occur with lynx, wget and others.

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/glibc/+bug/1092691/+subscriptions