Details
A firewall is a piece of software that blocks unwanted incoming connections to a system. Apple has posted general documentation about the application firewall. http://support.apple.com/en-us/HT201642 A firewall minimizes the threat of unauthorized users from gaining access to your system while connected to a network or the Internet.
Solution
Perform the following to implement the prescribed state: Open System Preferences Select Security & Privacy Select Firewall Select Turn On Firewall Alternatively: Run the following command in Terminal: defaults write /Library/Preferences/com.apple.alf globalstate – int <value> Where <value> is: 1 = on for specific services 2 = on for essential services Impact: The firewall may block legitimate traffic. Applications that are unsigned will require special handling.
Supportive Information
The following resource is also helpful.
This security hardening control applies to the following category of controls within NIST 800-53: System and Communications Protection.This control applies to the following type of system Unix.