If you’re experiencing DNS related problems on Ubuntu, follow the below steps to use Google’s public DNS servers:

1. Open network interfaces:

   sudo vim /etc/network/interfaces

2. Add the following after “# dns-* options are implemented by the resolvconf package, if installed“:

   dns-nameservers 8.8.8.8 8.8.4.4

3. Restart the networking service:

   sudo /etc/init.d/networking restart

You should then be able to ping google.com and continue with what you were originally doing. If you experience further problems when using apt-get you will need to clear your cache:

1. Delete apt cache:

   sudo rm -rf /var/lib/apt/lists/*

2. Re-download packages:

   sudo apt-get update