Installing resolvconf in Ubuntu and Debian to set Permanent DNS Nameservers in Ubuntu and Debian

Unfortunately, because the /etc/resolv.conf is indirectly managed by the systemd-resolved service, and in some cases by the network service (by using initscripts or NetworkManager), any changes made manually by a user can not be saved permanently or only last for a while.

1. Update the system software packages and then install resolvconf from the official repositories by running the following commands.

    sudo apt update<br/>sudo apt install resolvconf
   

2. Start and enable resolvconf.service

    sudo systemctl start resolvconf.service
    sudo systemctl enable resolvconf.service<br/>sudo systemctl status resolvconf.service
   

3. Set Permanent DNS Nameservers and search domain

    sudo cat <<EOT >> /etc/resolvconf/resolv.conf.d/head
    nameserver 172.16.29.3
    nameserver 1.1.1.1
    nameserver 8.8.8.8
    search nginxf5.com
    EOT
   

4. Check the file

    cat /etc/resolvconf/resolv.conf.d/head
   

5. Save the changes and restart the resolvconf.service or reboot the system.

    sudo systemctl start resolvconf.service