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On 2010-12-07T22:07:09+00:00 Nigel wrote:

Created attachment 467312
Proposed patch to correct /etc/resolv.conf ordering.

Description of problem:
In currently version of NetworkManager in Fedora, IPv6 DNS nameservers are 
getting prioritised last in /etc/resolv.conf this doesn't seem right compared 
to prioritization of IPv6/IPv4 in general IP stacks (for instance, web 
browsing). 

Version-Release number of selected component (if applicable):
NetworkManager-0.8.1-10.git20100831.fc14.x86_64

How reproducible:
Always

Steps to Reproduce:
1. Set up a dual stack IPv6/IPv4 network, in my case radvd is announcing IPv6 
nameservers & IPs, dhcp is announcing IPv4 IPs & nameservers.
2.
3.
  
Actual results:

NetworkManager will write a /etc/resolv.conf in the following order:

domain <foo>
search <bar>
nameserver [IPv4 VPN Nameservers]
nameserver [IPv4 LAN Nameservers]
nameserver [IPv6 VPN Nameservers]
nameserver [IPv6 LAN Nameservers]

This means that DNS queries will happen over the IPv6 stack last.

Expected results:

My expected ordering is:

* IPv6 VPN Nameservers
* IPv4 VPN Nameservers
* IPv6 LAN Nameservers
* IPv4 LAN Nameservers

I prioritise IPv4 VPN over IPv6 LAN in consideration that there will be
some IPv4 only VPN networks around for a while.

Additional info:

I have a patch that has worked over the last week on my home/personal
laptop that corrects this issue. (Attached)

Reply at: https://bugs.launchpad.net/ubuntu/+source/network-
manager/+bug/734781/comments/0

------------------------------------------------------------------------
On 2012-05-03T19:44:16+00:00 Dan wrote:

hm... certainly ip6_vpn_config should go above ip4_device_config
(ignoring the fact that we don't have any ipv6 vpns yet...). Not sure if
there's any rule that says ipv6 should go above ipv4 in general. I think
for now it's probably better to keep ipv4 first, since people are more
likely to accidentally have a broken ipv6 config than they are to
accidentally have a broken ipv4 config...

Reply at: https://bugs.launchpad.net/ubuntu/+source/network-
manager/+bug/734781/comments/3

------------------------------------------------------------------------
On 2012-05-03T22:02:47+00:00 Dan wrote:

That was my reasoning too, since people are *still* trying to work out
IPv6.  And you can still get IPv6 answers via IPv4 nameservers too,
which depends on the IPv4 nameservers being set up correctly with AAA
records of course.

Note that glibc also has a maximum of *3* 'nameserver' entries in
resolv.conf, so if we really had both IPv4 VPN & normal and IPv6 VPN and
normal nameservers, we'd be one over the limit.  The only way to fix
this is to use a local caching nameserver.

glibc queries the nameservers in the order they are listed in
resolv.conf, so if the IPv4 servers don't know the address of the IPv6
machine it should fail and glib will query the IPv6 server.  The apps
themselves are the things that request AAA records (IPv6) instead of the
A records and they are the ones that decide what to do with the records
that actually get returned too.  So unless the app is badly coded, is
there a real difference which nameservers are first?  Is ordering
necessary to work around bad servers?

Reply at: https://bugs.launchpad.net/ubuntu/+source/network-
manager/+bug/734781/comments/4

------------------------------------------------------------------------
On 2012-05-08T17:48:29+00:00 Dan wrote:

(In reply to comment #2)
> Is ordering necessary to work around bad servers?

There are some nameservers that drop AAAA requests on the floor. (Not
many, and probably a lot fewer than there were a few years ago.) Using
such a nameserver when you also have a global IPv6 address (presumably
via a tunnel) will cause DNS resolution to become really slow, because
you have to wait for glibc to time out on the AAAA request every time.

Presumably you're not likely to find such a broken nameserver listening
on an IPv6 address. (Though, this being the internet, there's probably
at least one, somewhere out there.) So that would be a point in favor of
putting the IPv6 servers first. Not sure how it weighs against the "more
likely to have broken IPv6 than IPv4" point.

Reply at: https://bugs.launchpad.net/ubuntu/+source/network-
manager/+bug/734781/comments/5

------------------------------------------------------------------------
On 2012-07-29T03:40:26+00:00 Nigel wrote:

(In reply to comment #2)

> So unless the app is badly coded, is there a real difference which
> nameservers are first?  Is ordering necessary to work around bad servers?

Nearly two years down the track, and I'm beginning to agree, although,
since then, systems like OpenVPN are getting close to IPv6 (OpenVPN 2.3
Alpha 3 has IPv6 support [1]), so at least correct priority of IPv6 VPN
name servers over IPv4/6 LAN nameservers will be somewhat important in
the near future.

It was my understanding when I filed the patch that there was likely an
RFC that denoted the correct ordering of nameservers et al. in IPv4/v6
environments to match the expected prioritization of when IPv4 and IPv6
is available for a service/destination, IPv6 is chosen. But I haven't
managed to find one, so my original reasoning appears to be out the
window.

[1]: http://community.openvpn.net/openvpn/wiki/ChangesInOpenvpn23

Reply at: https://bugs.launchpad.net/ubuntu/+source/network-
manager/+bug/734781/comments/7

------------------------------------------------------------------------
On 2012-08-16T17:58:03+00:00 Fedora wrote:

This message is a notice that Fedora 14 is now at end of life. Fedora 
has stopped maintaining and issuing updates for Fedora 14. It is 
Fedora's policy to close all bug reports from releases that are no 
longer maintained.  At this time, all open bugs with a Fedora 'version'
of '14' have been closed as WONTFIX.

(Please note: Our normal process is to give advanced warning of this 
occurring, but we forgot to do that. A thousand apologies.)

Package Maintainer: If you wish for this bug to remain open because you
plan to fix it in a currently maintained version, feel free to reopen 
this bug and simply change the 'version' to a later Fedora version.

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we were unable to fix it before Fedora 14 reached end of life. If you 
would still like to see this bug fixed and are able to reproduce it 
against a later version of Fedora, you are encouraged to click on 
"Clone This Bug" (top right of this page) and open it against that 
version of Fedora.

Although we aim to fix as many bugs as possible during every release's 
lifetime, sometimes those efforts are overtaken by events.  Often a 
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The process we are following is described here: 
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Reply at: https://bugs.launchpad.net/ubuntu/+source/network-
manager/+bug/734781/comments/8


** Changed in: network-manager (Fedora)
       Status: Unknown => Won't Fix

** Changed in: network-manager (Fedora)
   Importance: Unknown => Medium

-- 
You received this bug notification because you are a member of Desktop
Packages, which is subscribed to network-manager in Ubuntu.
https://bugs.launchpad.net/bugs/734781

Title:
  NM fails to list IPv6 nameservers before IPv4 ones

Status in network-manager package in Ubuntu:
  Fix Released
Status in network-manager package in Fedora:
  Won't Fix

Bug description:
  Binary package hint: network-manager

  Description:  Ubuntu 10.10
  Release:      10.10

  network-manager:
    Asennettu: 0.8.1+git.20100810t184654.ab580f4-0ubuntu2.1
    Ehdokas:   0.8.1+git.20100810t184654.ab580f4-0ubuntu2.1
    Versiotaulukko:
   *** 0.8.1+git.20100810t184654.ab580f4-0ubuntu2.1 0
          500 http://fi.archive.ubuntu.com/ubuntu/ maverick-proposed/main amd64 
Packages
          100 /var/lib/dpkg/status
       0.8.1+git.20100810t184654.ab580f4-0ubuntu2 0
          500 http://fi.archive.ubuntu.com/ubuntu/ maverick/main amd64 Packages

  
  When using dual-stack IPv4/IPv6 connectivity the nameservers are in wrong 
order in /etc/resolv.conf The IPv6 nameservers should be first.

  Same bug: https://bugzilla.redhat.com/show_bug.cgi?id=661150

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