Mac OS X: Using a Firewall to Protect Your Computer

Excerpted from Mac Help)

Mac OS X includes firewall software you can use to block unwanted network communication with your computer. You can use a firewall to protect all of the services available in Mac OS X, such as Personal File Sharing, Windows Sharing, and Remote Login. Using a firewall protects the services on your computer from users on other networks or the Internet.

Note: When you select a service in the Services pane of Sharing preferences, it is automatically selected in the Firewall pane. To prevent that service while the firewall is on, turn off the service in the Services pane.

To enable firewall protection for a service on your computer:

1. Open System Preferences.
2. Click Sharing.
3. Select the service you want to share.

   Note: Firewall protection is automatically turned on for that service.

4. Click Firewall to make sure the corresponding firewall is enabled.
5. To turn off firewall protection for any service while your firewall software is turned on, turn off the service by deselecting it in the Services pane.

You can not edit the firewall ports used by built-in services. They are enabled and disabled automatically when you turn the corresponding service on or off in the Services pane.

I Can't Change Firewall Settings

The firewall built into Mac OS X includes ports for each of the services listed in the Services pane of Sharing preferences.

You can not enable or disable these firewall ports directly. They are enabled and disabled automatically when you turn the corresponding service on or off in the Services pane.

You can control the firewall settings for other ports that you add using the Firewall pane of System Preferences.

To turn the firewall for a built-in service on or off:

1. Open System Preferences.
2. Click Sharing.
3. Now click Services.
4. Enable OR disable the service.

Firewall access for the service is set accordingly.

If you have questions, please contact the ITS Help Desks at helpdesk@psu.edu.