For IPv6:
nameserver 2001: 4860: 4860 :: 8888
nameserver 2001: 4860: 4860 :: 8844
For IPv6-only, you can use Google Public DNS64 instead of the above IPv6 address.
Save and exit.
Restart the Internet clients you are using.
Check if your settings are working properly by using the link at the bottom of the article.
Also, if you are using the DHCP client software to override the settings in the /etc/resolv.conf file, you will need to install the client by editing the client's configuration file.
Backup /etc/resolv.conf:
sudo cp / etc / resolv . conf / etc / resolv . conf . auto
Edit /etc/dhcp3/dhclient.conf:
sudo vi / etc / dhcp3 / dhclient . conf
If there is a line containing domain-name-servers, write the IP addresses for future reference.
Replace the line containing domain-name-servers with or add the following line:
For IPv4:
prepend domain - name - servers 8.8 . 8.8 , 8.8 . 4.4 ;
For IPv6:
prepend domain - name - servers 2001 : 4860 : 4860 :: 8888 , 2001 : 4860 : 4860 :: 8844 ;
For IPv6-only, you can use Google Public DNS64 instead of the above IPv6 address.
Save and exit.
Check that your settings are working properly by referring to the article below.
The link to check for new DNS settings is correct: Instructions for checking Google DNS settings after changes
Good luck.
You can refer to: The best and fastest DNS list of Google, VNPT, FPT, Viettel, Singapore