Little Snitch: Rule List, Map, and Summary: Our computers are constantly connecting to other computers around the world.

If you’re someone who’s been made aware of the prevalent privacy violations occurring in today’s computer age, you’ve likely thought something like, “I need to turn on the firewall, right?”


The answer, for Windows users, is a resounding, “YES!”

But, the answer for Mac users can be a bit confusing.

Mac users have often chosen Apple’s Mac as their computer brand for it’s positive reputation regarding computer virus vulnerability. Most Mac users have never seen or known of a computer virus on their Mac. Apple has done a very good job at patching vulnerabilities. Though, some would say that Apple could prioritize security even more.


The previous known computer viruses to affect Apple’s Mac Operating system were ‘in the wild’ for several days, if not weeks, before Apple patched them. And, if you’ve done your homework, you know that computer viruses can spread from your computer to another computer without you ever seeing them. Worst case scenario, these computer viruses can steal data from you, putting your identity at risk. At least, computer viruses can bog down the snappiness of your beloved Mac, and plague your Mac with unwanted ads and unexpected behavior.

So, what do you do if you’re a Mac user and get a computer virus? First things first, don’t panic.


Be sure you’re running Software Update. Installing all of the updates provided by Apple will ensure you’ve got all of the most current security patches. On newer Macs, Software Update is inside of the Mac App Store.

If you’ve fully updated your Mac’s software and still see symptoms, I highly recommend calling AppleCare support at 1-800-MY-APPLE. If your Mac is infected by a computer virus that’s very new, Apple needs to know about it.


Even if your Mac isn’t covered by AppleCare at the time you’re having the issue, you can explain to them that you think it’s a computer virus and that they should document it. AppleCare support will report to Apple Engineering and they’ll get to work on a security patch to be released as a software update.

What should you do in the meantime?

This is what this article is really all about.

There are several tools a Mac user can and arguably should deploy to protect themselves while using their computers. We started off asking if we should turn on a firewall and that’s what we’re going to get into the weeds about. Apple’s operating system comes with a firewall, but it’s not very customizable. And, importantly, it only monitors and blocks incoming internet traffic. If you end up with a computer virus, the Apple firewall won’t stop that computer virus from spreading via your computer. More important, it won’t stop that computer virus from sending your sensitive personal data.


Enter Little Snitch by Objective Development. Little Snitch is a firewall app that, once installed, stays running on your Mac. Little Snitch monitors both incoming and outgoing internet connection attempts. And, Little Snitch alerts you of any new and potentially unwanted apps or computer viruses if they try to send or receive data over the internet.

Little Snitch, at first, alerts you of every app’s connection to the internet. It asks you if you’d like to allow or deny the data connection. It allows you to temporarily, or permanently allow or deny the connection. Eventually, Little Snitch ends up with a set of rules you’ve created, and it becomes quiet. Only when you’ve installed new software, whether intentionally or unintentionally, will Little Snitch spring to life and alert you of new connection attempts.


Little Snitch: The Connection Alert

Little Snitch does so much more, too. When an application or operating system process tries to make a connection, Little Snitch will give you information about the software or process. With this information, you can see whether the application or process is created by a Developer registered with Apple, as well as fine details about the connection attempt.


With Little Snitch 4, an application or process can easily be allowed some connections, and be denied others. Little Snitch’s Network Monitor interface has simple checkbox switches to indicate whether the application or process is allowed or denied connections. And, you can easily toggle those rules with a single click.


Perhaps Little Snitch’s most notable feature is Automatic Profile Switching. This feature allows your Mac to automatically change it’s set of rules based on where you’re using your Mac. This means you can have more security and faster internet when using coffee shop and airport wifi, or use less data when using your phone’s tethering for internet on your Mac. You can make sets of rules which temporarily limit those apps you normally want to work, like an online backup like Backblaze, from eating up your internet connection. And, you can stop your Mac from logging into your email while you’re in an unsecured wifi location like a coffee shop or airport unless you’re connected to a VPN like Private Internet Access.


Objective Development goes even further in it’s endeavor to help Mac users secure their Macs. The recent news about computer webcam and microphones being activated remotely has created more awareness than ever. In response, Objective Development has created Micro Snitch. Micro Snitch is another Mac App which runs all the time on your Mac. Micro Snitch is much more simple in it’s job than Little Snitch. It only comes to life to alert you if and when your webcam and microphone have been activated. Micro Snitch will alert you whether or not your Mac webcam’s green LED lights up or not. Combined, Little Snitch and Micro Snitch help Mac users rest easy in knowing they’re less vulnerable in today’s internet wild west.

Take a look at Objective Development’s website and get a trial of Little Snitch and Micro Snitch. And, if you decide to buy them, tell them I sent you.


They’ve been kind enough to provide me with copies of their software so that I could evaluate on my own and choose whether it’s something I’d recommend to my friends and clients. I’ve been using them for over a year and I wholeheartedly recommend them!

About the Author:

Sky Doherty is an independent Technology Consultant, a retired Apple Support Employee, Apple Certified Associate and Apple Certified Technician.