How to configure Leopard’s firewall

There are two schools of thought when it comes to the software firewall built into OS X.

 

One school says that it’s not necessary. Firewalls prevent unapproved connections from opening ports on a computer’s network interface. (Ports are how a software service talks to a network. You can think of a port as a window in a wall; some ports are left open on purpose to allow incoming and outgoing data traffic.) But by default, OS X doesn’t leave many ports open. In contrast, most versions of Windows ship with a bunch of open ports, which is one reason that operating system is a riper target for malicious hackers. And while Leopard leaves open more ports than earlier versions of Mac OS X, so far there have been no known attacks on those default services.

 

The other school (to which I belong) says that the best security mantra is “never assume.” As you install and use programs on your system, you often open ports without realizing it. And there’s always the possibility that a chink in OS X’s armor will lead to a wave of new exploits. That’s why I recommend that all Mac users turn on OS X’s built-in firewall.

 

Source: Mac World