Step 6: Configure the Mac OS X Firewall

Mac OS X includes firewall software you can use to block unwanted network communication with your computer. Using a firewall protects your computer from users on other networks or the Internet. Follow the steps below for your operating system: 

• Mac OS X 10.4 (Tiger)
• Mac OS X 10.5 (Leopard)

Mac OS X 10.4 (Tiger) 

To turn on the firewall:

1. From the Apple menu, select System Preferences.
2. In the System Preferences window, click Sharing.
3. Select the Firewall tab.
4. Click the lock icon to make changes.
5. If prompted, enter the admin userid and password.
   
6. Select the Firewall tab and click the Start button to turn on the firewall.
   
7. Note: Advanced users, to enable firewall exceptions (see Securing Your Machine: Definitions):
   • Uncheck any program or service you DO NOT wish to accept incoming network connections.
   • Check any program or service you DO wish to accept incoming connections.
   • Click New to add a service or Edit to modify one and follow the on-screen instructions. You will not be able to edit firewall ports used by built-in services.
     
8. Click the lock icon to prevent further changes and close the Sharing window.

Mac OS X 10.5 (Leopard)

To select the level of protection:

1. From the Apple menu, select System Preferences.
2. In the System Preferences window, click Sharing.
3. Select the Firewall tab.
4. Click the lock icon to make changes.
5. If prompted, enter the admin userid and password.
6. Select Allow only essential services.
   
   Note: Services that are turned on such as File Sharing will appear in the list. To prevent incoming connections from one of these services, turn off the service in Sharing preferences.
7. Click the lock icon to prevent further changes and close the Sharing window.
   
   

Other Security Tips

Last Updated:  1/17/08