Quad9 is a free security solution that uses DNS to protect your systems against the most common cyber threats. Please follow the steps below to configure Ubuntu 18.04 LTS to use Quad9.
From the Ubuntu desktop, select the drop down menu in the top right corner of the screen, expand either Wired or Wireless Connected based on your connection and then select Wired or Wireless Settings.
Select the gear icon next to your connection.
Select the IPv6 tab, disable Automatic DNS and then enter the appropriate Quad9 IP addresses for your needs. For more information on which server is right for you, please visit our Quad9 IPs and Other Settings page. We strongly suggest entering both a primary and a secondary address as a precaution. Multiple IP addresses can be entered in the list by using comas.
Once you have the addresses entered, simply select Apply to complete the set up process.