Radio Silence 3.4
Radio Silence is an invisible, always-active outbound firewall for Mac from developer Juuso Salonen that blocks individual apps from accessing the internet, backed by a real-time network connection monitor. Version 3.4 adds clear inbound/outbound distinction to the connections list.
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About Radio Silence 3.4 for Mac
Radio Silence is an outbound application firewall for macOS developed by Finnish developer Juuso Salonen, first released in 2010 and rebuilt on Apple's network extensions starting with version 3.x (moving away from the harder-to-debug kernel extensions used in earlier versions). It requires macOS 10.15 or later, works with both Apple Silicon and Intel Macs, and is sold exclusively through the developer's own website with a free trial and a 30-day money-back guarantee, since firewalls like Radio Silence can't be distributed through the Mac App Store due to the operating-system-level access they require. Version 3.4 adds the ability to distinguish outbound and inbound connections directly in the connections list, with the port column now showing the port connected to for inbound connections. What makes Radio Silence stand out among Mac firewalls is its commitment to being completely invisible and maintenance-free once configured: the firewall runs automatically at startup, stays active even when the app's window is closed, and never interrupts the user with pop-up windows or alerts. Rather than requiring constant permission prompts like some competing tools, Radio Silence lets users build a simple block list of apps that aren't allowed to access the internet, while a real-time network monitor shows every connection an app or process makes, making it easy to spot and block misbehaving software with a single click.