Create a world-readable (permission 644) resolv.conf and add some nameservers to it.
For Example:
# Quad9. nameserver 9.9.9.9 nameserver 2620:fe::fe nameserver 149.112.112.112 # Localhost. nameserver 127.0.0.1 nameserver ::1
You generally don’t need to restart any network management services for the changes to take effect.
However, some system services or programs may have entered a failed state while DNS resolution was disabled.
Do a quick reboot to kick-start them unless you want to manually double-check that all running services and programs have recovered.
You may want to configure additional parameters for the resolv.conf file. See the man 5 resolv.conf manual for details on other domain resolution configuration options.