Firewall provides system-wide protection against in-app trackers via a local VPN profile that blocks tracking-related requests the apps make in real-time.
It installs a local VPN profile in the Settings > VPN section of the iOS, so to enable Firewall you need to allow installing that VPN profile.
To install Firewall's VPN profile:
Open the Firewall tab
Scroll down and tap Install Configuration
Press Allow and follow further instructions
Once the profile is installed, you can find it in iOS Settings > VPN > Firewall by 1Blocker.
1Blocker provides a handy switch that lets you manage Firewall right from the app.
When it is enabled, the toggle will be highlighted in green, and you will see the status set as You're protected:
Also, you can quickly enable, pause or disable Firewall from the Overview tab of 1Blocker.
Since the data is routed only locally, no information about your activity leaves your device.
Firewall is currently available only in the iOS version of 1Blocker.