Application Firewall is a crucial component for securing your macOS environment. It helps to control incoming network connections by allowing or blocking them based on predefined rules. This is particularly important for preventing unauthorized access and protecting sensitive data. In this article, we will explore how to configure and manage the Application Firewall on macOS, providing practical examples and commands to guide you through the process.

Examples:

1. Enable Application Firewall:
To enable the Application Firewall on macOS, you can use the following steps:

• Open System Preferences.


• Go to Security & Privacy.


• Click on the Firewall tab.


• Click on the lock icon to make changes (you may need to enter your administrator password).


• 
  

  Click "Turn On Firewall."

  
  

  Alternatively, you can enable the firewall via the command line using pfctl:

  
  

  sudo /usr/libexec/ApplicationFirewall/socketfilterfw --setglobalstate on

  
  

2. Add an Application to the Firewall:
To allow a specific application to receive incoming connections, you can add it to the firewall exceptions list:

• Open System Preferences.


• Go to Security & Privacy.


• Click on the Firewall tab.


• Click on Firewall Options.


• Click the "+" button to add an application.


• 
  

  Select the application you want to allow and click Add.

  
  

  Via command line:

  
  

  sudo /usr/libexec/ApplicationFirewall/socketfilterfw --add /path/to/application

  
  

3. Block an Application:
To block an application from receiving incoming connections, you can remove it from the exceptions list:

• Open System Preferences.


• Go to Security & Privacy.


• Click on the Firewall tab.


• Click on Firewall Options.


• 
  

  Select the application you want to block and click the "-" button.

  
  

  Via command line:

  
  

  sudo /usr/libexec/ApplicationFirewall/socketfilterfw --blockApp /path/to/application

  
  

4. Check Firewall Status:
To check the status of the Application Firewall, use the following command:

   sudo /usr/libexec/ApplicationFirewall/socketfilterfw --getglobalstate

This will return either "Firewall is enabled. (State = 1)" or "Firewall is disabled. (State = 0)".

5. View Firewall Logs:
To view the logs generated by the Application Firewall, you can use the log command:

   sudo log show --predicate 'process == "socketfilterfw"' --info