According to the Wikipedia
Firewall is a network security system that monitors and controls the incoming and outgoing network traffic based on predetermined security rules.
Whatever the Wikipedia says we will look what that is useful for us.
You don’t want to be computer genius to handle basic firewall configurations. This is not an antivirus software.
Why do we use Firewall
1. Can stop malicious software try to connect to internet.
Let’s say there is a Trojan horse that send your pictures to someone else. We can stop this.
2. Can monitor what are the software that currently connected to internet and how much data it is using.
3. Can stop background updates.
If you have a media player that try to update every day we can stop that. Updating and getting new features are cool but we can stop if it does too much.
