To change nameservers permanently in Ubuntu Desktop Version we need to update /etc/resolvconf/resolv.conf.d/head file with desired list.
Following is the procedure to change nameservers permanently:
Open /etc/resolvconf/resolv.conf.d/head file with your favourite editor:
sudo vim /etc/resolvconf/resolv.conf.d/head
Add following lines to /etc/resolvconf/resolv.conf.d/head, save & exit from the file
nameserver 126.96.36.199 nameserver 188.8.131.52
Run following command to change nameservers permanently:
sudo resolvconf -u
After running above commands nameservers in your desktop version will get updated with new list as mentioned in /etc/resolvconf/resolv.conf.d/head file.
To conform this open /etc/resolve.conf and validate.