You may navigate to your Mac’s Security & Privacy section by simply clicking on Apple icon on the top left corner of your desktop and clicking on System Preferences… wording. That window will bring you to the new window as pictured below in which you can see whether the Firewall has been enabled by clicking on the Menu Title “Firewall”.
You can also Turn On and Off your Mac firewall by using Terminal a little piece of a command. Make sure you are familiar to using terminal commands.
To Turn the firewall on, you may copay and paste the following command which will then activate the firewall in a blink of an eye. A password is required to execute this action.
sudo defaults write /Library/Preferences/com.apple.alf globalstate -int 1
To turn the firewall off, you may simply copy and paste the same command by replacing 1 (one) with 0 (zero).
Such will deactivate firewall. If you ask me how important it is to keep Mac firewall On, I would say: I would never turn my Mac firewall Off.
When your Mac firewall is turned off, your Mac is exposed to the Internet threats and exploits coming your way in multitudes.
For example, you are in a cafeteria and browsing the net using a guest/public WiFi (network). Such networks are either protected with weak passwords or are totally unsecured. On such, anyone having penetration skills can have a total access to your Mac exploiting some known vulnerabilities.
Who knows if a bad guy who is deliberately penetrating computers connected to the same shared and unsecured network! Chances are that he might be stealing sensitive information from those Mac that have firewall turned off against those that did not.
Same applies if you are in a shared office network or unsecured network of any public areas such as subway, park, hotel, library and so on.
Cyber security and Internet penetration field is in the heights of technology exploration and critical exploits and testings. Many malicious codes are being written just to an attempt of stealing sensitive information from a person to the large scale of state owned agencies. Also such codes are tested in daily basis to learn about its damages such as how genuine operating systems are altered and backdoors are open to further exploit system. Internet penetration via open firewall also comprise private and confidential information stealing in a global and organized manner that is hard to trackback when systems and system operators are hidden behind complex layers of VPN services running and replicating behind tor and leaving no trace behind.
In most of the scenarios, simply by strengthening the Mac Firewall may help you prevent many of the malicious penetrations coming your way via unsecured public WiFi networks you just connected.
Haven’t you Turned On your Mac Firewall yet? Common, man! Do it! This is a great preventive method to keep your private contents secure. And it does not cost a dime.