SYSTEMd resolved enable debug log

Ubuntu 18+  Currently in use  systemd-resolved  As  dns  Resolution server , You need to check the detailed log again , This can be done by .

Edit profile

sudo systemctl edit systemd-resolved

Add the following configuration and save it

[Service]
Environment=SYSTEMD_LOG_LEVEL=debug

Restart the service

systemctl restart systemd-resolved

Check the log

journalctl -u systemd-resolved -f