[Bug 1642973] Re: DNS stops working when changing networks

[gpothier]

Ok, here it goes. /run/resolvconf is attached.

It looks like there are several dnsmasq processes, but it is also the
case when things work. Here are the processes when it doesn't work:

gpothier at tadzim3:addons$ ps aux |grep dnsmasq
libvirt+  1614  0.0  0.0  50200  1324 ?        S    nov14   0:00 /usr/sbin/dnsmasq --conf-file=/var/lib/libvirt/dnsmasq/default.conf --leasefile-ro --dhcp-script=/usr/lib/libvirt/libvirt_leaseshelper
root      1615  0.0  0.0  50172    20 ?        S    nov14   0:00 /usr/sbin/dnsmasq --conf-file=/var/lib/libvirt/dnsmasq/default.conf --leasefile-ro --dhcp-script=/usr/lib/libvirt/libvirt_leaseshelper
nobody   24365  0.0  0.0  54308  3768 ?        S    11:05   0:00 /usr/sbin/dnsmasq --no-resolv --keep-in-foreground --no-hosts --bind-interfaces --pid-file=/var/run/NetworkManager/dnsmasq.pid --listen-address=127.0.1.1 --cache-size=0 --conf-file=/dev/null --proxy-dnssec --enable-dbus=org.freedesktop.NetworkManager.dnsmasq --conf-dir=/etc/NetworkManager/dnsmasq.d
gpothier 32400  0.0  0.0  15448   976 pts/6    S+   13:54   0:00 grep --color=auto dnsmasq

And here's what syslog says with the pkill:

Nov 18 13:56:01 tadzim3 dnsmasq[24365]: time 1479488161
Nov 18 13:56:01 tadzim3 dnsmasq[1614]: time 1479488161
Nov 18 13:56:01 tadzim3 dnsmasq[24365]: cache size 0, 0/0 cache insertions re-used unexpired cache entries.
Nov 18 13:56:01 tadzim3 dnsmasq[1614]: cache size 150, 0/0 cache insertions re-used unexpired cache entries.
Nov 18 13:56:01 tadzim3 dnsmasq[24365]: queries forwarded 6542, queries answered locally 3
Nov 18 13:56:01 tadzim3 dnsmasq[1614]: queries forwarded 0, queries answered locally 0
Nov 18 13:56:01 tadzim3 dnsmasq[24365]: queries for authoritative zones 0
Nov 18 13:56:01 tadzim3 dnsmasq[1614]: queries for authoritative zones 0
Nov 18 13:56:01 tadzim3 dnsmasq[1614]: server 127.0.1.1#53: queries sent 0, retried or failed 0
Nov 18 13:56:01 tadzim3 dnsmasq[24365]: server 192.168.0.2#53: queries sent 129, retried or failed 103


** Attachment added: "resolvconf.tgz"
   https://bugs.launchpad.net/ubuntu/+source/resolvconf/+bug/1642973/+attachment/4779409/+files/resolvconf.tgz

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https://bugs.launchpad.net/bugs/1642973

Title:
  DNS stops working when changing networks

Status in resolvconf package in Ubuntu:
  Incomplete

Bug description:
  Since upgrading to 16.10 I am having frequent DNS failures. It usually happens when I change networks and after resume from suspend, for example going to home from work, or vice versa. When this happens, connectivity is fine (I can ping 8.8.8.8 for instance), but I cannot resolve names (eg. google.com).
  Restarting network-manager instantaneously fixes the issue.

  Curiously I have not found this bug on Launchpad. Here is some related
  stuff I've seen:

  https://bugs.launchpad.net/ubuntu/+source/resolvconf/+bug/1640286
  (as described, it seems specific to Chrome)

  https://bugs.launchpad.net/ubuntu/+source/network-manager/+bug/1592721
  (DNS resolution issues with VPNs, but it looks like it has been solved; at least I am not affected anymore)

  http://askubuntu.com/questions/838948/16-10-fail-to-resolve-dns
  (forum post that describes a similar issue, but again for VPNs)

  ProblemType: Bug
  DistroRelease: Ubuntu 16.10
  Package: resolvconf 1.79ubuntu1
  ProcVersionSignature: Ubuntu 4.8.0-27.29-generic 4.8.1
  Uname: Linux 4.8.0-27-generic x86_64
  ApportVersion: 2.20.3-0ubuntu8
  Architecture: amd64
  CurrentDesktop: GNOME
  Date: Fri Nov 18 11:07:53 2016
  InstallationDate: Installed on 2015-01-23 (664 days ago)
  InstallationMedia: Ubuntu-GNOME 14.04.1 LTS "Trusty Tahr" - Release amd64 (20140722.2)
  PackageArchitecture: all
  SourcePackage: resolvconf
  UpgradeStatus: Upgraded to yakkety on 2016-10-30 (19 days ago)

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