Ubuntu - Networking - DNS - Set nameservers to outside nameservers

sudo vi /etc/network/interfaces

Update the dns-nameservers line as shown:

/etc/network/interfaces

. . .
iface eth0 inet6 static
        address 2604:A880:0800:0010:0000:0000:00B2:0001
        netmask 64
        gateway 2604:A880:0800:0010:0000:0000:0000:0001
        autoconf 0
        dns-nameservers 8.8.8.8 8.8.4.4

Refresh your network settings:

sudo ifdown eth0 && sudo ifup eth0