For whatever reason, you want to change your DNS, you need to change it at resolv.conf
First change your directory to /etc.
cd /etc
if you type in ls -l, you will see resolv.conf file.
you have to sudo or su to make changes
sudo nano resolv.conf
if there is existing dns, you can hash it out. Just put # in front of the address
and then type in the new nameservers
you can use openDNS, Googles DNS or any DNS that you prefer.
OpenDNS 1: 208.67.222.222
OpenDNS 2: 208.67.220.220
ctrl + O
Enter
ctrl +x