Take a look at your Desktop and/or interface. Be it MATE (desktop/laptop), Phosh (Pinephone/Librem), or KDE. We use several buttons/shortcuts to programs everyday. Some of these need the internet. Some do not.
Have you minimized access to programs who do not need the internet? Did you know some programs secretly “call home” and share data/your IP address with 3rd parties (sometimes sold)? The most ideal setup is one which is restricted wherever possible, but not up to the point where your setup becomes unusable.
Here we are going to use a Hot Off the Press News example to demonstrate how to allow networking only to those programs requiring it (such as web browsers, encrypted messengers, etc). Other programs like VLC Media player, GIMP (image manipulation), and Libre Office do NOT need ANY networking for full functionality. So why do we allow it? Because this is default behavior, we accept it. We are going to change that today.
Firejail 