ping 8.8.8.8 works but ping www.google.com doesn't

You need a Name Server in your /etc/resolv.conf file. Edit your /etc/resolv.conf and add a working Name Server. Google provides a free one, 8.8.8.8.

Do this:

$ nano /etc/resolv.conf

Place this as the first non-commented line:

nameserver 8.8.8.8

You can verify this functionality with:

$ ping -c10 www.google.com

You can make this change permanent by adding the line to this file your /etc/resolvconf/resolv.conf.d/head file.

The marked answer actually doesn't work on Ubuntu 18.04.01. To fix this issue, here's what I did:

• Execute sudo gedit /usr/lib/systemd/resolv.conf
• Paste nameserver 8.8.8.8 (and/or any other nameserver(s) you want), then save and exit.
• Add a symlink by executing sudo ln -sf /usr/lib/systemd/resolv.conf /etc/resolv.conf

Credits to https://askubuntu.com/a/1050280/899241

Could you post a link to the page that told you that file resolv.conf should be empty? My guess is that it is misleading at best.

Edit that file with command sudo nano /etc/resolv.conf and put there a single line:

nameserver 8.8.8.8

That should fix your name resolution and the various programs that use it - ping, apt-get, etc.

You also ought to investigate why resolv.conf is empty. Perhaps your DHCP server isn't configured properly.