Change DNS Ubuntu
This is small example how to manually change DNS in Ubuntu. This example working for most linux distro.
What is DNS?The Domain Name System (DNS) is a hierarchical naming system built on a distributed database for computers, services, or any resource connected to the Internet or a private network. DNS translates domain names meaningful to humans into the numerical identifiers associated with networking equipment for the purpose of locating and addressing these devices worldwide. For example google.com DNS records looks like
google.com. 1 IN A 74.125.232.20
google.com. 1 IN A 74.125.232.16
google.com. 1 IN A 74.125.232.17
google.com. 1 IN A 74.125.232.18
google.com. 1 IN A 74.125.232.19Change DNS recommend if you use VPN and dont want to be tracked! Some websites can determine your location using DNS records. So lets change our DNS to google public DNS. However you can use your VPN provider DNS or any other DNS servers.
1) To change DNS in Ubuntu we need edit file /etc/resolv.conf
Open Terminal from Applications -> Accessories -> Terminal and use this command to edit DNS zones file
sudo nano /etc/resolv.conf
if you’re not root system will ask to confirm editing with password
2) Comment existing records using # symbol and add new DNS records like:
nameserver x.x.x.x
where x.x.x.x is your new DNS server.
For google public DNS use 8.8.8.8 and 8.8.4.4
if you use StrongVPN you can use their own DNS servers: 216.131.94.5 and 216.131.95.20
On my example I comment my local settings #nameservers 192.168.1.1 and add 2 new records for google DNS
use Ctrl + x to save file and sure confirm all
3) Some linux services can change DNS zones files automatically so to prevent this we will lock file.
Use this command to lock file
sudo chattr +i /etc/resolv.conf
To unlock (if you want to change DNS again) you will need this command:
sudo chattr -i /etc/resolv.conf
All done, DNS changed 
Reading is quite informative about VPN. This enables that even a one-person company can reap the benefits of vpn4all technology.
Thank you for sharing this information about the need for Change DNS for more security.