DNS resolution ceased to work after update

[Thiemo]

Hi

I did a Focal install on 14th of May 2020, could work until in the night of 16th of May 2020 and in the morning of the 18th of May 2020 I could not resolve domain names anymore. I can ping DNS servers but the resolution to IP addresses fails. I have switched on automatic installation of security relevant updates.

I can reproduce the behaviour with a fresh install accepting all the updates there are. I did not try to find out which update is the cause.

See the behaviour below where I even have tried to work around by removing the DNS server of my router:
thiemo @ Fujitsu-HO ~ :-( % systemd-resolve --status 20-05-18 12:54
Global
       LLMNR setting: no
MulticastDNS setting: no
  DNSOverTLS setting: no
      DNSSEC setting: no
    DNSSEC supported: no
          DNSSEC NTA: 10.in-addr.arpa
                      16.172.in-addr.arpa
                      168.192.in-addr.arpa
                      17.172.in-addr.arpa
                      18.172.in-addr.arpa
                      19.172.in-addr.arpa
                      20.172.in-addr.arpa
                      21.172.in-addr.arpa
                      22.172.in-addr.arpa
                      23.172.in-addr.arpa
                      24.172.in-addr.arpa
                      25.172.in-addr.arpa
                      26.172.in-addr.arpa
                      27.172.in-addr.arpa
                      28.172.in-addr.arpa
                      29.172.in-addr.arpa
                      30.172.in-addr.arpa
                      31.172.in-addr.arpa
                      corp
                      d.f.ip6.arpa
                      home
                      internal
                      intranet
                      lan
                      local
                      private
                      test

Link 2 (enp0s25)
      Current Scopes: DNS
DefaultRoute setting: yes
       LLMNR setting: yes
MulticastDNS setting: no
  DNSOverTLS setting: no
      DNSSEC setting: no
    DNSSEC supported: no
         DNS Servers: 139.18.25.33
                      139.18.25.34
                      77.59.232.36
                      62.167.241.5
                      62.2.107.35
                      62.2.121.84
                      62.2.121.88
                      fd00::7eff:4dff:feaa:2528
                      2001:638:902:1::10
          DNS Domain: ~.
thiemo @ Fujitsu-HO ~ % host -v myworkspaceinet.post.ch 20-05-18 12:54
Trying "myworkspaceinet.post.ch"
;; connection timed out; no servers could be reached

thiemo @ Fujitsu-HO ~ :-( % alias pong 20-05-18 12:55
pong='ping -c3'
thiemo @ Fujitsu-HO ~ % pong 139.18.25.33 20-05-18 12:58
PING 139.18.25.33 (139.18.25.33) 56(84) bytes of data.
64 bytes from 139.18.25.33: icmp_seq=1 ttl=246 time=39.9 ms
64 bytes from 139.18.25.33: icmp_seq=2 ttl=246 time=39.0 ms
64 bytes from 139.18.25.33: icmp_seq=3 ttl=246 time=39.4 ms

--- 139.18.25.33 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2003ms
rtt min/avg/max/mdev = 39.000/39.431/39.868/0.354 ms

Kind regards

Thiemo

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: network-manager 1.22.10-1ubuntu1
ProcVersionSignature: Ubuntu 5.4.0-29.33-generic 5.4.30
Uname: Linux 5.4.0-29-generic x86_64
ApportVersion: 2.20.11-0ubuntu27
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: KDE
Date: Mon May 18 13:03:40 2020
InstallationDate: Installed on 2020-05-15 (3 days ago)
InstallationMedia: Kubuntu 20.04 LTS "Focal Fossa" - Release amd64 (20200423)
IpRoute:
 default via 192.168.178.1 dev enp0s25 proto dhcp metric 100
 169.254.0.0/16 dev enp0s25 scope link metric 1000
 192.168.178.0/24 dev enp0s25 proto kernel scope link src 192.168.178.33 metric 100
IwConfig:
 enp0s25 no wireless extensions.

 lo no wireless extensions.
RfKill:

SourcePackage: network-manager
UpgradeStatus: No upgrade log present (probably fresh install)
nmcli-con:
 NAME UUID TYPE TIMESTAMP TIMESTAMP-REAL AUTOCONNECT AUTOCONNECT-PRIORITY READONLY DBUS-PATH ACTIVE DEVICE STATE ACTIVE-PATH SLAVE FILENAME
 Wired connection 1 3ce8a4c9-c011-3344-bbfd-9618a499a099 ethernet 1589799780 Mon May 18 13:03:00 2020 yes -100 no /org/freedesktop/NetworkManager/Settings/1 yes enp0s25 activated /org/freedesktop/NetworkManager/ActiveConnection/1 -- /etc/NetworkManager/system-connections/Wired connection 1.nmconnection
nmcli-dev:
 DEVICE TYPE STATE IP4-CONNECTIVITY IP6-CONNECTIVITY DBUS-PATH CONNECTION CON-UUID CON-PATH
 enp0s25 ethernet connected full full /org/freedesktop/NetworkManager/Devices/2 Wired connection 1 3ce8a4c9-c011-3344-bbfd-9618a499a099 /org/freedesktop/NetworkManager/ActiveConnection/1
 lo loopback unmanaged unknown unknown /org/freedesktop/NetworkManager/Devices/1 -- -- --
nmcli-nm:
 RUNNING VERSION STATE STARTUP CONNECTIVITY NETWORKING WIFI-HW WIFI WWAN-HW WWAN
 running 1.22.10 connected started full enabled enabled enabled enabled enabled

[Sebastien Bacher (seb128)]

Thank you for your bug report. Could you check in /var/log/dpkg.log what was updated before you started getting the issue?

[Thiemo (thiemo-kellner)]

Please find dpkg.log attached. I extracted with the following command timely suspects but of those 140 only 131 are unique. I do not know why unless there were updates twice for some reason.

grep -F '2020-05-16 23:' /var/log/dpkg.log | grep -F 'status installed'

2020-05-16 23:12:46 status installed python3-more-itertools:all 4.2.0-1build1
2020-05-16 23:12:46 status installed python3-attr:all 19.3.0-2
2020-05-16 23:12:47 status installed qgis-providers-common:all 3.10.4+dfsg-1ubuntu2
2020-05-16 23:12:47 status installed python3-pyqt5.qtsql:amd64 5.14.1+dfsg-3build1
2020-05-16 23:12:47 status installed ttf-bitstream-vera:all 1.10-8
2020-05-16 23:12:48 status installed libfcgi0ldbl:amd64 2.4.0-10build1
2020-05-16 23:12:48 status installed libgslcblas0:amd64 2.5+dfsg-6build1
2020-05-16 23:12:48 status installed python3-ipython-genutils:all 0.2.0-1ubuntu1
2020-05-16 23:12:49 status installed libsqlite3-mod-spatialite:amd64 4.3.0a-6build1
2020-05-16 23:12:49 status installed fonts-lyx:all 2.3.4.2-2
2020-05-16 23:12:49 status installed libqscintilla2-qt5-l10n:all 2.11.2+dfsg-6
2020-05-16 23:12:49 status installed python3-retrying:all 1.3.3-4
2020-05-16 23:12:50 status installed libhdf5-cpp-103:amd64 1.10.4+repack-11ubuntu1
2020-05-16 23:12:50 status installed libfcgi-bin:amd64 2.4.0-10build1
2020-05-16 23:12:50 status installed qhelpgenerator-qt5:amd64 5.12.8-0ubuntu1
2020-05-16 23:12:51 status installed libqwt-qt5-6:amd64 6.1.4-1.1build1
2020-05-16 23:12:52 status installed libqt5serialport5:amd64 5.12.8-0ubuntu1
2020-05-16 23:12:53 status installed libspatialindex6:amd64 1.9.3-1build1
2020-05-16 23:12:54 status installed libqscintilla2-qt5-15:amd64 2.11.2+dfsg-6
2020-05-16 23:12:54 status installed libqt5designercomponents5:amd64 5.12.8-0ubuntu1
2020-05-16 23:12:55 status installed python3-zipp:all 1.0.0-1
2020-05-16 23:12:55 status installed libqt53dcore5:amd64 5.12.8+dfsg-0ubuntu1
2020-05-16 23:12:55 status installed libqt53dlogic5:amd64 5.12.8+dfsg-0ubuntu1
2020-05-16 23:12:56 status installed python3-webencodings:all 0.5.1-1ubuntu1
2020-05-16 23:12:56 status installed libqgis-native3.10.4:amd64 3.10.4+dfsg-1ubuntu2
2020-05-16 23:12:56 status installed libllvm10:amd64 1:10.0.0-4ubuntu1
2020-05-16 23:12:56 status installed libqgis-core3.10.4:amd64 3.10.4+dfsg-1ubuntu2
2020-05-16 23:12:57 status installed python3-decorator:all 4.4.2-0ubuntu1
2020-05-16 23:12:57 status installed libjs-jquery-ui:all 1.12.1+dfsg-5
2020-05-16 23:12:58 status installed python3-pyparsing:all 2.4.6-1
2020-05-16 23:12:58 status installed libgsl23:amd64 2.5+dfsg-6build1
2020-05-16 23:12:58 status installed libclang1-10:amd64 1:10.0.0-4ubuntu1
2020-05-16 23:12:58 status installed libassimp5:amd64 5.0.1~ds0-1build1
2020-05-16 23:12:59 status installed python3-cycler:all 0.10.0-3
2020-05-16 23:13:00 status installed qtattributionsscanner-qt5:amd64 5.12.8-0ubuntu1
2020-05-16 23:13:00 status installed python3-kiwisolver:amd64 1.0.1-3build1
2020-05-16 23:13:00 status installed grass-doc:all 7.8.2-1build3
2020-05-16 23:13:00 status installed libqt53dinput5:amd64 5.12.8+dfsg-0ubuntu1
2020-05-16 23:13:01 status installed libtcl8.6:amd64 8.6.10+dfsg-1
2020-05-16 23:13:01 status ...

[Launchpad Janitor (janitor)]

[Expired for network-manager (Ubuntu) because there has been no activity for 60 days.]