[Bug 1880258] Re: Add trailing dot to make connectivity-check.ubuntu.com. absolute and reduce NXDOMAIN warning noise

[Łukasz Zemczak]

Hello MarcH, or anyone else affected,

Accepted systemd into groovy-proposed. The package will build now and be
available at
https://launchpad.net/ubuntu/+source/systemd/246.6-1ubuntu1.2 in a few
hours, and then in the -proposed repository.

Please help us by testing this new package.  See
https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how
to enable and use -proposed.  Your feedback will aid us getting this
update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug,
mentioning the version of the package you tested, what testing has been
performed on the package and change the tag from verification-needed-
groovy to verification-done-groovy. If it does not fix the bug for you,
please add a comment stating that, and change the tag to verification-
failed-groovy. In either case, without details of your testing we will
not be able to proceed.

Further information regarding the verification process can be found at
https://wiki.ubuntu.com/QATeam/PerformingSRUVerification .  Thank you in
advance for helping!

N.B. The updated package will be released to -updates after the bug(s)
fixed by this package have been verified and the package has been in
-proposed for a minimum of 7 days.

** Changed in: systemd (Ubuntu Groovy)
       Status: In Progress => Fix Committed

** Tags added: verification-needed verification-needed-groovy

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to systemd in Ubuntu.
https://bugs.launchpad.net/bugs/1880258

Title:
  Add trailing dot to make connectivity-check.ubuntu.com. absolute and
  reduce NXDOMAIN warning noise

Status in network-manager package in Ubuntu:
  Fix Released
Status in systemd package in Ubuntu:
  Fix Committed
Status in network-manager source package in Bionic:
  New
Status in systemd source package in Bionic:
  In Progress
Status in network-manager source package in Focal:
  Confirmed
Status in systemd source package in Focal:
  Fix Committed
Status in network-manager source package in Groovy:
  New
Status in systemd source package in Groovy:
  Fix Committed
Status in network-manager source package in Hirsute:
  Fix Released
Status in systemd source package in Hirsute:
  Fix Committed

Bug description:
  [impact]

  systemd-resolved emits a disturbingly large amount of NXDOMAIN log
  messages that do not actually indicate any real problem

  [test case]

  see original description, or look at any log from any recent Ubuntu
  system, or search google for endless complaints about NXDOMAIN
  messages logged by Ubuntu

  [regression potential]

  any regression would likely be isolated to systemd-resolved handling
  of a NXDOMAIN response from its upstream nameserver, including
  possibly failing to resolve a hostname or delays in resolving
  hostnames

  [scope]

  this is needed for all releases; the patch is not upstream, but
  carried by Ubuntu

  [original description]

  I normally don't like this, but it's a one-character change so it's
  easier to start with the solution:

  diff -u -r1.1 /usr/lib/NetworkManager/conf.d/20-connectivity-ubuntu.conf
  --- /usr/lib/NetworkManager/conf.d/20-connectivity-ubuntu.conf
  +++ /usr/lib/NetworkManager/conf.d/20-connectivity-ubuntu.conf
  @@ -1,2 +1,2 @@
   [connectivity]
  -uri=http://connectivity-check.ubuntu.com/
  +uri=http://connectivity-check.ubuntu.com./

  Making this name absolute instead of relative avoids spurious
  resolutions of "connectivity-check.ubuntu.com.your_domain." This
  removes a fair amount of NXDOMAIN error noise in journalctl.

  Observing the issue and the fix requires 3 terminals:

  1. tcpdump -i any 'port domain'
  2. journalctl --boot -u systemd-resolved -f

  3. nmcli c down "Wired connection 1"; nmcli c up "Wired connection 1"
   => observe the NXDOMAIN noise over a couple few minutes

  Now make the hostname absolute with the trailing dot above and run:
     systemctl reload NetworkManager
  Wait 1 min for things to stabilize. Test again:

  nmcli c down "Wired connection 1"; nmcli c up "Wired connection 1"
   => observe non-zero but significantly reduced NXDOMAIN noise over a couple few minutes

  Originally reported at https://askubuntu.com/a/1242611/117217

  Plenty of people annoyed by NXDOMAIN warnings, just Google it.

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/network-manager/+bug/1880258/+subscriptions