how to configure a firewall for mac os x using terminal

Configure A Firewall Using Terminal How To Do It
Configure A Firewall Using Terminal Install And Use
Configure A Firewall Using Terminal Mac OS X

Configure A Firewall Using Terminal How To Do It

That firewall can be configured to be more secure, but doing so is for advanced users only; if you dont know how to do it already, you probably shouldnt attempt it at this time.) In the Firewall configuration tab, below the three options, you should see a list of network services that are currently authorized to accept or deny incoming connections.

Firewalls prevent unapproved connections from opening ports on a computers 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 doesnt 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.

Configure A Firewall Using Terminal Mac OS X

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.

Configure A Firewall Using Terminal Install And Use

As you install and use programs on your system, you often open ports without realizing it.

And theres always the possibility that a chink in OS Xs armor will lead to a wave of new exploits.

But though the firewall interface in Mac OS X 10.5 is indeed quite different from that in earlier versions of the OS, its still relatively easy to use, especially since the release of the 10.5.1 update.

Whats new In previous editions of OS X, you configured the firewall in the Sharing preference pane.

Also, the Block All Incoming Connections option actually left a number of ports open, including any service running as the root user; none of those open services were shown in the user interface.

The firewall also broke some programs, such as Skype, that change their internal code when they run.

The reason is that the firewall creates a digital signature for each program that tries to communicate across the network interface.

That signature enables OS X to know if the programs code has been modified; if it has, OS X will refuse to run it.

Such modified programs would bounce on the Dock a few times, and then shut down.

OS X 10.5.1 remedied these flaws by changing that second option to Allow Only Essential Services, tightening and documenting which essential services are allowed, and prompting users to reactivate programs (like Skype) that change themselves, instead of simply breaking them.

Set Firewall Options: By selecting the Set Access For Specific Services And Applications option, you can control incoming network traffic.

Configuring the firewall Leopards Allow All Incoming Connections option is the functional equivalent of the old Stop button: it turns your firewall off.

The Allow Only Essential Services option will block anything except a few default networking services, such as Bonjour.

It prevents file sharing, remote access, and other optional services.

You should use this option only if you really want to block everything.

I use this option when Im on potentially hostile networks, such as those in hotels or public hotspots, and dont want to bother with manually turning off all my shared services (see Firewalls on the Road).

The third option, Set Access For Specific Services And Applications, is the one I recommend for everyday use.

Previous versions of OS X used a technology known as stateful packet inspection a fancy way of saying the firewall blocked ports that werent being held open for use by approved applications.

An application firewall like the one in Leopard blocks traffic targeting specific applications, not specific ports.

Leopard still includes a stateful-packet-inspection firewall, called ipfw, but by default its set to let all traffic through.

How To Configure A Firewall For Mac Os X Using Terminal