Network Debugging

You can set systemd-networkd to work in debug mode so that you can analyze log files with debugging information to help troubleshoot networking problems.

The following procedure turns on network debugging by adding a drop-in file in /etc/systemd to customize the default systemd configuration in /usr/lib/systemd.

1. Run the following command as root to create a directory with this exact name, including the .d extension:

   mkdir -p /etc/systemd/system/systemd-networkd.service.d/

2. Run the following command as root to establish a systemd drop-in unit with a debugging configuration for the network service:

    cat > /etc/systemd/system/systemd-networkd.service.d/10-loglevel-debug.conf << "EOF"
        [Service]
        Environment=SYSTEMD_LOG_LEVEL=debug
        EOF
   

3. Reload the systemctl daemon and restart the systemd-networkd service for the changes to take effect:

    systemctl daemon-reload
        systemctl restart systemd-networkd
   

4. Verify that your changes took effect:

   `systemd-delta --type=extended`
   

5. View the log files by running this command:

   `journalctl -u systemd-networkd`
   

6. After debugging the network connections, turn debugging off by deleting the drop-in file:

   `rm /etc/systemd/system/systemd-networkd.service.d/10-loglevel-debug.conf`