For all those unfortunate enough to have a very bad DNS from their service provider, the ability to set your own DNS is a must. Here I will be giving a short tutorial on how to set a DNS using network manager under gnome. What you need to do is :-

1. Go to networkmanager -> edit connections. This can be done by right clicking on the gnome panel icon and clicking on edit connections.
2. Select the current connection that you are using, either wired or wireless.
3. Edit that connection. In IPV4 settings, if you are using DHCP, use DHCP (Addresses only).
4. Now, the DNS Servers menu will be enabled. In that field enter the DNS IPs with comma separation.
5. I am using the google’s free DNS at 8.8.8.8 and 8.8.4.4
6. Close the refresh the connection by left clicking on the panel icon and clicking on the connection you wish to refresh.

NetworkManager DNS Setting

Here’s a screen-shot of the final window.

That’s it. All your requests from now on will be resolved through google DNS and not the default DNS from your service provider.