Block outgoing connections on Mac OS using a free firewall app

The built-in firewall on macOS is capable of blocking incoming network connections. What if you want to block outgoing internet connections on a Mac? Here is a solution. Finally, good firewall software is available for the macOS; it’s called Lulu. Little Snitch and Radio Silence are the most popular and standalone firewall apps among macOS users. But LuLu is equally powerful, and above all, it’s a free application for managing internet connections in macOS. Lulu works on the latest macOS versions like High Sierra, Catalina, and even Big Sur. Check out our review of Lulu and the way to download and install it on your Mac. We will also tell you how to use LuLu to block Mac apps and services from accessing the internet.

How to block Mac (macOS) apps from accessing internet

Many people purchase Little snitch and Radio Silence for blocking Adobe CC apps like Photoshop from accessing the Internet. They assert that paying for a firewall program like Radio Silence (costs 9$) is much affordable than owning an Adobe license. We are against using a firewall for any illegal activities like blocking the activation services of Adobe, FL Studio, or any other paid app on a Mac. But if you are looking for an open-source firewall application to protect your Mac, get Lulu now.

Download Lulu for macOS from the official website.

If you are using the macOS Big Sur 11 and up, there is a new version of the Lulu, download v2.4.2.

An antivirus alone can’t prevent emerging threats, botnets, and ransomware, which causes more damage to an internet-connected Mac. Now the good thing is that you can use Lulu and an Antivirus like Avast for the complete protection of your Mac. Lulu allows you to decide which all macOS apps can access the internet. It shows a notification (like in the screenshot above) whenever an app tries to connect to the internet, and you can choose to allow or block it. This way, it helps you stop malware and other unknown applications sending sensitive data to the internet.

Block outgoing connections on a Mac using Lulu

These days many of the macOS apps (e.g., Adobe CC suite) can disable counterfeit installations through the internet. They have inbuilt tools to monitor the apps continuously and check them with their activation servers. If Adobe finds you are using it without a license, they can automatically tamper and automatically deactivate the app. This process requires an active internet connection and is an example of a legit usage case. What if your Mac has malware infection and if it is sending your data to remote locations. It is possible since Mac’s inbuilt firewall cannot block outgoing connections. You always need to use an app blocker like Lulu for a secure Mac experience.

Configuring Lulu as your Mac’s default firewall to control outgoing connections is very simple.

• Install the app from the above link and restart your Mac. When you restart, you will see the above screen.
• Tick the button to “Allow Apple programs” and untick the option to “Allow Already Installed Applications” and click Next.
• Now the Lulu icon will be added to the macOS menu bar; click on it  to manage rules and preferences.

Lulu will notify you when an app starts sending external requests, just as shown in the first images on this page. All you need to stop outgoing connection on your Mac is to hit the “block button.” This rule is added to Lulu’s settings, and you can edit or delete it later but right-clicking on the corresponding row.

Another main advantage of Lulu is that you can check the threat level of all apps that makes outgoing connections with the VirusTotal database. Click on the VirusTotal icon when you see the outgoing connection notification; it does a live scan and tells you the result. This feature allows you to confirm whether the app making the internet connection is malware or not.

Lulu is an open-source app for the Mac. Its source code is available on Github— so anyone can audit the application’s security status if they are concerned. However, open-source apps have its disadvantage too. If there are any loopholes within the code, malware creators can use it to target the Lulu app’s computers. So if you are using Lulu, always use the latest version. You can check and update it from the preferences menu.

Alternative free firewall app to prevent outgoing network traffic on macOS: TCPBlock

TCPBlock was one of the reliable free firewall apps for the macOS in the past. Although it’s the interface is confusing for the users, it did work in old macOS versions. The app is outdated for use in new-age computers. However, if your Mac runs macOS 10.11 EL Capitan, and below, you may consider TCPBlock (click here) for blocking outgoing connections.

TCP block also has a notification system to let you know about the outgoing internet activity. But the alerts appear in the macOS notification area if you enable the option in settings. TCPBlock is not as interactive as the Lulu; you have to adjust many settings manually. But those who are using old Macs have fewer choices in the free category.