On Ubuntu 20.10, if a user creates an interface that is unmanaged by NetworkManager (e.g. a tunnel interface), NetworkManager will overwrite it's DNS config on systemd-resolved. A fix for this already exists upstream - https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/commit/4ddfc5c14b6f82d802988332d92a7e05b18d1ff0
To reproduce, one can create a WireGuard interface via `wg-quick` and assign DNS servers via systemd-resolve, observe that `systemd-resolve --status` contains the servers set previously and then suspend the machine and wake it up and then check that `systemd-resolve --status` output no longer contains the previously set servers.
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ProblemType: Bug
ApportVersion: 2.20.11-0ubuntu50.5
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: ubuntu:GNOME
DistroRelease: Ubuntu 20.10
InstallationDate: Installed on 2020-12-01 (69 days ago)
InstallationMedia: Ubuntu 20.10 "Groovy Gorilla" - Release amd64 (20201022)
Package: network-manager 1.26.2-1ubuntu1
PackageArchitecture: amd64
ProcVersionSignature: Ubuntu 5.8.0-43.49-generic 5.8.18
RfKill:
Tags: groovy
Uname: Linux 5.8.0-43-generic x86_64
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip lpadmin lxd plugdev sambashare sudo
_MarkForUpload: True
nmcli-nm:
RUNNING VERSION STATE STARTUP CONNECTIVITY NETWORKING WIFI-HW WIFI WWAN-HW WWAN
running 1.26.2 connected started full enabled enabled enabled enabled enabled
apport information