Mac Firewall Apps

The built in firewall in macOS only controls incoming traffic. If you want to stop apps from calling home or contacting unknown servers, you'll need a third-party firewall. You have choices based on the degree of control and the features you need or want. The following area all marketed as consumer firewalls and are designed to provide services on a single Mac.

Little Snitch

Little Snitch from Objective Development offers the most comprehensive set of features. You can set it up so that it notifies you of every new or changed connection forcing you to make a choice to allow or deny it. You can also let it run in silent mode and review the connections later, choosing which ones to prohibit. Little Snitch provides maps and graphs that show you where your outgoing traffic is going with information on IP addresses, ports and protocols. You can import lists of IP addresses and domains from known bad actors to automatically block them but be careful. Sometimes legitimate services like analytics you may have running on your own web sites end up getting blocked. A single license for Little Snitch will set you back $59.

LuLu

LuLu from Objective-See is a free and open-source product. When you install it, it defaults to permitting traffic to all of the apps you already have installed and to all Apple apps. Thereafter, when a new connection is detected, LuLu will ask if you want to grant permanent or temporary access to the app. If you want to block any of your existing apps, you can add or edit rules for them.

Radio Silence

Radio Silence is a well-designed Mac app that operates totally behind the scenes unless you summon it There's no dock or menu bar icon. When you summon the app and let it run, it keeps a list of every app, daemon and process that accesses the Internet, along with info on ports, protocols and IP addresses. You can go through the list and choose which ones you want to block. Like LuLu, you can also manually add apps to the block list. Radio Silence is $9 and comes with a 30-day money back guarantee. A single license can be used on all the Macs you own.

Lockdown Privacy Desktop

If you want a free, open-source firewall with preconfigured rules that places a minimal load on your computer, Lockdown Privacy Desktop and its companion iOS app Lockdown Privacy Ad Blocker VPN do a great job on both platforms. The setup procedure is minimal, and the basic configuration is done for you. Lockdown also lets you create custom rules and is capable of blocking any site. It does not block apps like the other titles in this review, however you can run it in conjunction with LuLu or Radio Silence. It comes with rules pre-configured to block:

• Amazon Trackers
• Crypto mining
• Data Trackers
• Email Trackers
• Facebook Trackers
• Game marketing
• General marketing
• Google shopping
• Marketing trackers
• Ransomware
• Reporting
• Snapchat trackers
• WhatsApp trackers