[Bug 1010724] Re: No IPv6 nameservers in Ubuntu 12.04

[Thomas Hood]

Strainu, thanks for the report.

Strainu wrote:
> Apparently, the local dnsmasq server does not listen on IPv6, which is wrong. The server should also listen on ::1:53, to allow IPv6-only connections.

The problem is certainly not that dnsmasq lacks IPv6 DNS *support*.  It
has very good support.

To begin with, the dnsmasq documentation says: "On IPv6-enabled boxes,
dnsmasq can both talk to upstream servers via IPv6 and offer DNS service
via IPv6. On dual-stack (IPv4 and IPv6) boxes it talks both protocols
and can even act as IPv6-to-IPv4 or IPv4-to-IPv6 forwarder."

At the moment (due to a disk failure, but that's another story) I'm
running Ubuntu 11.10 with network-manager and standalone dnsmasq (i.e.,
not dnsmasq run by NM).  Dnsmasq *does* listen on ::1:53.  The command

    netstat -nl

includes the following lines in its output.

    tcp6       0      0 :::53                   :::*                    LISTEN     
    udp6       0      0 :::53                   :::*           

The following command

    dig aaaa -6 google.com

works fine, giving the following output.

    ; <<>> DiG 9.7.3 <<>> aaaa -6 google.com
    ;; global options: +cmd
    ;; Got answer:
    ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 11095
    ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

    ;; QUESTION SECTION:
    ;google.com.			IN	AAAA

    ;; ANSWER SECTION:
    google.com.		274	IN	AAAA	2a00:1450:4007:804::1009

    ;; Query time: 1 msec
    ;; SERVER: ::1#53(::1)
    ;; WHEN: Sun Jun 10 21:53:03 2012
    ;; MSG SIZE  rcvd: 56

The commands

    dig @127.0.0.1 aaaa -6 google.com
    dig @::1 aaaa -6 google.com

work equally well.

The following commands all work equally well.

    host google.com
    host google.com 127.0.0.1
    host google.com ::1

Furthermore the following works equally well

    ping google.com

whether "127.0.0.1" or "::1" is listed in /etc/resolv.conf.

Strainu wrote:
> Alternatively, the resolvconf package should write the actual DNS server [address] received through DHCPv6 in /etc/resolv.conf

Even if dnsmasq didn't support IPv6 this would not be an attractive
solution since it would be inconsistent with the way the IPv4 case was
handled.

Continuing in another comment.

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https://bugs.launchpad.net/bugs/1010724

Title:
  No IPv6 nameservers in Ubuntu 12.04

Status in “resolvconf” package in Ubuntu:
  New

Bug description:
  I have IPv6 activated on Ubuntu 12.04 LTS and I receive an IPv6
  address through DHCPv6. However, requests sent through IPv6 fail. For
  example:

  strainu at emily:~$ dig aaaa -6 google.com

  ; <<>> DiG 9.8.1-P1 <<>> aaaa -6 google.com
  ;; global options: +cmd
  ;; connection timed out; no servers could be reached

  But:

  strainu at emily:~$ dig aaaa google.com

  ; <<>> DiG 9.8.1-P1 <<>> aaaa google.com
  ;; global options: +cmd
  ;; Got answer:
  ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 60426
  ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 4, ADDITIONAL: 4

  ;; QUESTION SECTION:
  ;google.com.			IN	AAAA

  ;; ANSWER SECTION:
  google.com.		94	IN	AAAA	2a00:1450:400d:805::1000

  
  Looking into /etc/resolv.conf, I see:

  strainu at emily:~$ cat /etc/resolv.conf 
  # Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
  #     DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
  nameserver 127.0.0.1
  search lan

  And with netstat:

  strainu at emily:~$ netstat -ln
  Active Internet connections (only servers)
  Proto Recv-Q Send-Q Local Address           Foreign Address         State      
  tcp        0      0 127.0.0.1:53            0.0.0.0:*               LISTEN     
  tcp        0      0 127.0.0.1:631           0.0.0.0:*               LISTEN     
  tcp6       0      0 ::1:631                 :::*                    LISTEN     
  udp        0      0 127.0.0.1:53            0.0.0.0:*                          
  udp        0      0 0.0.0.0:68              0.0.0.0:*                          
  udp        0      0 0.0.0.0:5353            0.0.0.0:*                          
  udp        0      0 0.0.0.0:38399           0.0.0.0:*                          
  udp6       0      0 :::47973                :::*                               
  udp6       0      0 :::5353                 :::*          

  Apparently, the local dnsmasq server does not listen on IPv6, which is
  wrong. The server should also listen on ::1:53, to allow IPv6-only
  connections. Alternatively, the resolvconf package should write the
  actual DNS server received through DHCPv6 in /etc/resolv.conf

  ProblemType: Bug
  DistroRelease: Ubuntu 12.04
  Package: resolvconf 1.63ubuntu14
  ProcVersionSignature: Ubuntu 3.2.0-24.39-generic 3.2.16
  Uname: Linux 3.2.0-24-generic x86_64
  ApportVersion: 2.0.1-0ubuntu8
  Architecture: amd64
  Date: Sat Jun  9 02:27:02 2012
  InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Release amd64 (20111012)
  PackageArchitecture: all
  SourcePackage: resolvconf
  UpgradeStatus: Upgraded to precise on 2012-05-28 (11 days ago)

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