Introduction

A firewall is a security system that acts as a protective boundary between a network and the outside world. Macintosh OS X includes firewall software, called ipfw, which you can use to restrict what information is communicated between the Internet and your computer.

Enabling the OS 10.5 (LEOPARD) Firewall

• Open System Preferences by clicking on the icon in the dock.
   
• Open the Security preference window.
  
• Select the Firewall tab.
  
• To turn off your firewall and allow all acess to your computer, select Allow all incoming connections.
• To turn your firewall on with user control over which programs have access to the internet, select Set access for specific services and applications.
• To let Leopard detemine what to give access to, select Allow only essential services.

Enabling the OS 10.4 (TIGER) Firewall

• Open System Preferences by clicking on the icon in the dock.
  
• Open the Sharing preference window.
  
• Select the Firewall tab.
  
• On the Firewall tab, either:
  • Enable the OS X Firewall by clicking the Start button.
  • Disable the OS X Firewall by clicking the Stop button. This disables the firewall; your computer and network are then vulnerable to intrusions.
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