I can confirm the issue is the following line in /etc/ppp/ip- up.d/0000usepeerdns as previously mentioned :
cp -a "$REALRESOLVCONF" "$REALRESOLVCONF.pppd-backup.$PPP_IFACE" The variable expansion of that line is : cp -a /run/systemd/resolve/stub-resolv.conf /run/systemd/resolve/stub-resolv.conf.pppd-backup.ppp0 I had to modify the shebang line of that script from : #!/bin/sh -e to : #!/bin/sh to get past that line and output debugging output I inserted, which included : ls -l /run/systemd/resolve/stub-resolv.conf -rw-r--r-- 1 systemd-resolve systemd-resolve 720 Jan 17 21:47 /run/systemd/resolve/stub-resolv.conf ls -l /run/systemd/resolve/stub-resolv.conf.pppd-backup.ppp0 -rw------- 1 root root 720 Jan 17 21:47 /run/systemd/resolve/stub-resolv.conf.pppd-backup.ppp0 So 'cp -a' isn't copying the permissions. Oddly, $? is 0 after running that 'cp -a' line, therefor seems correct, also umask is 0022, so I'm not sure what is going wrong. Anyway a fix seems to be to change the following line in /etc/ppp/ip-up.d/0000usepeerdns from : cp -a "$REALRESOLVCONF" "$REALRESOLVCONF.pppd-backup.$PPP_IFACE" to: cp "$REALRESOLVCONF" "$REALRESOLVCONF.pppd-backup.$PPP_IFACE" chmod 644 "$REALRESOLVCONF.pppd-backup.$PPP_IFACE" For Ubuntu 18.04 setups that have the pppconfig package installed, the following lines in /etc/ppp/ip-up.d/0dns-up probably should be changed from : /bin/cp -Lp "$RESOLVCONF" "$RESOLVBAK" || exit 1 /bin/cp -Lp "$TEMPRESOLV" "$RESOLVCONF" || exit 1 chmod 644 "$RESOLVCONF" || exit 1 to: /bin/cp -Lp "$RESOLVCONF" "$RESOLVBAK" || exit 1 chmod 644 "$RESOLVBAK" || exit 1 /bin/cp -Lp "$TEMPRESOLV" "$RESOLVCONF" || exit 1 chmod 644 "$RESOLVCONF" || exit 1 -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to resolvconf in Ubuntu. https://bugs.launchpad.net/bugs/1778946 Title: No dns resolution after closing a vpn/pptp connection Status in network-manager package in Ubuntu: Confirmed Status in ppp package in Ubuntu: Confirmed Status in resolvconf package in Ubuntu: Confirmed Bug description: step to reproduce set a VPN connection configured to connect a Microsoft vpn server (pptp) internet acces is ok enable the vpn connection using the applet on the top right corner of the desktop internet still ok ping works disable the vpn connection ping doesn't works with a host but works if i specify an ip address ping: xx.net: Nom ou service inconnu As a workaround, i disable the ethernet link and re-enable it name resolution is now ok ProblemType: Bug DistroRelease: Ubuntu 18.04 Package: network-manager 1.10.6-2ubuntu1 ProcVersionSignature: Ubuntu 4.15.0-23.25-generic 4.15.18 Uname: Linux 4.15.0-23-generic x86_64 NonfreeKernelModules: nvidia_modeset nvidia ApportVersion: 2.20.9-0ubuntu7.2 Architecture: amd64 CurrentDesktop: ubuntu:GNOME Date: Wed Jun 27 18:09:30 2018 IfupdownConfig: # interfaces(5) file used by ifup(8) and ifdown(8) auto lo iface lo inet loopback InstallationDate: Installed on 2014-06-03 (1484 days ago) InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Release amd64 (20140417) IpRoute: default via 192.168.0.254 dev eth0 proto dhcp metric 20100 169.254.0.0/16 dev eth0 scope link metric 1000 192.168.0.0/24 dev eth0 proto kernel scope link src 192.168.0.47 metric 100 IwConfig: lo no wireless extensions. eth0 no wireless extensions. NetworkManager.state: [main] NetworkingEnabled=true WirelessEnabled=true WWANEnabled=true RfKill: SourcePackage: network-manager UpgradeStatus: Upgraded to bionic on 2018-05-10 (48 days ago) nmcli-dev: DEVICE TYPE STATE DBUS-PATH CONNECTION CON-UUID CON-PATH eth0 ethernet connected /org/freedesktop/NetworkManager/Devices/2 Connexion filaire 1 94806bba-1c68-46b6-87f4-a3eeeeaff6dd /org/freedesktop/NetworkManager/ActiveConnection/6 lo loopback unmanaged /org/freedesktop/NetworkManager/Devices/1 -- -- -- nmcli-nm: RUNNING VERSION STATE STARTUP CONNECTIVITY NETWORKING WIFI-HW WIFI WWAN-HW WWAN running 1.10.6 connected (site only) started limited enabled enabled enabled enabled enabled To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/network-manager/+bug/1778946/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp