14 DAY TRIAL // While ten years ago, most programs did not interact with the Internet, these days nearly every program does. Interaction between applications and the Internet can take just about any form, from the simplest check for updates when a program is launched to large chucks of information, used throughout the program. This may be an issue though, because many programs can communicate with the Internet, and they can do this without letting you know that they are doing it, and without telling you what they are doing. Fortunately, the Mac platform so far has been spared of the adware and malware plague that infests the Windows platform, and we are rarely, if ever, at risk by leaving the programs to do what they do. However, normally, there is nothing you can do, without serious knowledge of the Terminal and inner working of OS X, to stop an application from communicating with the Internet, should you wish it.
In comes Little Snitch, a preference pane that gives you total control over the gate between applications and the Internet.
Stay on top of things
The first issue is that normally you have no idea when and if a program connects to the Internet. Little Snitch solves this problem by actively monitoring outgoing transmissions and letting you know when a transmission that is not covered by the rules is about to take place. It will let you know what application is trying to transmit, to what server it is trying to transmit to, and on what port.
At this point you can tell Little Snitch whether you want to let the application do that, or not, and under what conditions. Thus you define a rule that is followed whenever similar transmissions occur.
It is important to note that this program only monitors outgoing transmissions. That is, it makes sure information does not leave your computer. However, it does not prevent information from coming into your computer. For incoming transmissions, the built in firewall in OS X is what you need. The two are complementary in that the firewall monitors incoming transmissions and Little Snitch monitors outgoing transmissions.
You control
Little Snitch works with rules, which tell it what to do when an application wants to send information over the Internet. It comes with a set of predefined rules, that ensure it doesn't interfere with any of the system components, but you can also define your own rules.
Whenever an application attempts to connect to the Internet, the program will alert you and ask you what it should do. In telling it what to do, you are also defining the rule for the program. You can basically allow or deny a program to send information over the Internet, and the time options are: once, until the respective application quits, and forever. Additionally, you must also choose a condition, which can be: same port, same server, same server and same port, or any network connection.
These rules can be changed at any time, and you can add them whenever you wish, without having to wait for the application to connect to the Internet.
Rules are handled in a certain order, depending on how specific they are, with specific rules taking precedence over more general rules. One example of this would be setting up a rule for a program so that it allows any network connections, then setting up a second rule for that program that denies any connection to a certain server. In essence, you are telling Little Snitch: let this program access everything except this one server. However, because of the way the program works with rules, you need to create two rules to get the result you want, and they will be handled depending on how specific they are, with the denial of one certain server being considered more important than the general allow everything rule.
Putting the cart before the horse
When trying out this program I have noticed that, in general, if the application that communicates with the internet is launched before Little Snitch, sometimes it will take the program a while to start snitching on its activity. This also happens if you delete a rule for an application. To get rid of this, simply launch Little Snitch before any other applications.
The Good Lets you stay on top of outbound internet communications and allow or forbid them.
The Bad It is a bit expensive; however, you can try it out with only a time limitation to see whether you really need it.
The Truth A great program for those who are very careful about the information their computer sends out over the Internet. For the rest of us, this program can be useful at times, but it is by no means a necessity.
Here are some screenshots, click to enlarge:
