OS X Mavericks: Set firewall access for services and apps
A firewall can protect your computer from unwanted contact initiated by other computers when you’re connected to the Internet or a network. If you turn on a sharing service, such as file sharing, OS X opens a specific port for the service to communicate through. When you open the Firewall pane of Security & Privacy preferences, any sharing services turned on in Sharing preferences, such as File Sharing or Remote Apple Events, appear in the list.
In addition to the sharing services in Sharing preferences, the list may include other services or apps that are allowed to access your computer from another system. For example, an app might have requested and been given access through the firewall, or it might be signed by a trusted certificate and therefore allowed access.
- Click the lock icon to unlock it, then type an administrator name and password.
- Click Firewall Options.
- Click Add (+), then select the services or apps you want to add. After an app is added, click its up and down arrows to allow or block connections through the firewall.
Blocking an app’s access through the firewall could interfere with or affect the performance of the app or other software that may depend on it.
When your computer detects a connection attempt to an app that is not enabled in Security & Privacy preferences or is not signed, a dialog asks whether you want to allow or deny the connection over the network or Internet.
To change the firewall access, you must first have the firewall turned on. For more information, see: