/etc/systemd/resolved.conf

Default Ubuntu 18.04 LTS:

#  This file is part of systemd.
#
#  systemd is free software; you can redistribute it and/or modify it
#  under the terms of the GNU Lesser General Public License as published by
#  the Free Software Foundation; either version 2.1 of the License, or
#  (at your option) any later version.
#
# Entries in this file show the compile time defaults.
# You can change settings by editing this file.
# Defaults can be restored by simply deleting this file.
#
# See resolved.conf(5) for details

[Resolve]
#DNS=
#FallbackDNS=
#Domains=
#LLMNR=no
#MulticastDNS=no
#DNSSEC=no
#Cache=yes
#DNSStubListener=yes

See also

• systemd-resolve: systemd-resolve --help, systemd-resolve --status, /etc/systemd/resolved.conf, systemd-resolve --statistics, resolvectl status, journalctl -u systemd-resolved, systemd-resolve --set-dns, systemctl start systemd-resolved