Firewall - Mac OS X 10.5 (Leopard) - Basic
Mac OS X 10.5 Leopard includes a new technology called the Application Firewall.1.) Click on the System Preferences icon on your dock:

2.) Click on Security:

3.) Click on Firewall:

4.) By default, the firewall will allow all incoming connections…which is not very helpful at all:

We need to change that by clicking on the 3rd option:

5.) Now click on the “+” button at the bottom left hand corner to choose which your application(s) you want to allow or block access by the firewall:

Select the application(s) you want and click on the Add button.
Note: A good rule of thumb would be to add all applications you may use on a regular basis to connect to the internet and used for productivity. We recommend the following applications: all Adobe Products (Acrobat, Illustrator, Photoshop, etc.), all Microsoft Products (Entourage, Excel, Word, Microsoft Updates, etc), iLife Series (iTunes, iLife, iPhoto, etc), Quicktime, Safari, Firefox, MacMail, or any communication client (iChat, AIM, Google Talk, etc.).
6.) After you have added your application(s), click on the Advanced button:

As you can see, the Stealth Mode is not turned on by default:

Turn on the Stealth Mode and click on the OK button:

7.): The applications you have added are allowed (incoming connections) by default, if you want to block some of your application(s), just click on that application and change to “Block incoming connections":



