I’m sure many of you know about this little app by now, but for those who don’t, here’s a little writeup on what exactly Little Snitch is, and why exactly it is awesome.

Firewalls are designed with one purpose in mind: to block unwanted incoming connections. But somehow everyone forgot about outgoing connections—those made from your system to some network server. Most of these connections are of course harmless. It could be the application checking for updates, or reporting anonymous system information back to the developer, or just a means for sending data like pictures up to a photo site. But if you’re concerned about security, it wouldn’t hurt to know what exactly these applications are sending back, and where to.

The goal of Little Snitch is to inform the user of these connections, and subsequently allow or block them. Once you install Little Snitch, it constantly monitors your system for outgoing connections. As soon as it detects something, it brings up an easy to understand decision box.

At the top lies the application icon so you quickly know what the app is talking about. Then it tells you which port the application is trying to use to connect to which server. There’s four possible options you can choose. You can allow any connection, connections to a particular port, the specific server, or the port and server. You can choose this to happen Once, until the application quits, or Forever, which creates a permanent rule. If you absolutely trust an application, you can choose “Allow Any Connection” and select the forever tab. Simple enough?

If you feel you’ve made a mistake, go into the Little Snitch configuration pane, which has everything laid out in a simple window. You can change the rules for a particular application, and even delete old rules which you don’t require any more. Little Snitch will identify any ‘dead’ applications with a yellow warning sign.

Network Monitor

The second leg of Little Snitch is the network monitor. It allows you to see all recent applications and services that have access the internet, as well see a live upload/download indicator for any particular service. Say for instance I’m browsing the web and my speed suddenly starts crawling. Bringing up the network monitor reveals that iTunes is currently going through some heavy network access—most probably downloading podcasts—which I can then take care of. I can also see if a download in Software Update is no longer progressing or when Safari stopped loading the YouTube download. This is especially useful for Safari 4 users since the blue loader has been replaced by the non-indicative “loading” spinner.

I don’t suppose many of you will be facing this problem, here’s a solution that Little Snitch presents that’s most important features. As many of you who know me must be knowing by now, I have a terrible internet connection. The only way for me to tell that it’s active is by refreshing a page in Safari, which again is not entirely accurate since some pages refuse to refresh while others show up just fine. Little Snitch is the only way I can tell when my network is internet-loaded with its dancing green and red lights in the menubar.

Little Snitch costs $30 for a license, not an impulse purchase for sure. If you want to check it out, the trial version runs for 3 hours, and can be restarted unlimited number of times.