When connected to the internet, even a standalone PC or a network of interconnected computers make easy targets for malicious software & hackers. Who want to steal your data. A firewall can offer the security that makes you less vulnerable and also protect your data from being compromised or your computers being taken hostage.
There are two types of firewalls: physical firewalls and software walls.
A physical firewall is like a moat that surrounds your network and helps keep your data safe from hackers. A physical firewall is your first line of defense from an attack.
A software firewall is your primary defensive for your individual computers. Software firewalls are like the guards inside the castle walls that check to see if you are suppose to be there.