Rethink DNS + Firewall

Rethink DNS + Firewall is the easiest way to monitor app activity, circumvent Internet censorship, block ads and trackers on your Android device.

Install RethinkDNS via F-Droid - https://f-droid.org/en/packages/com.celzero.bravedns/.

These are just a few tips.
You will probably have to adjust other settings for your environment anyway.

You can choose between many options.
Either use our DNScrypt server or any other DNScrypt server you like. DoH, DoT, ODoH and Rethinks-DNS-Server itself are also available. Even tor and SOCKS5 are included.
Also possible your own Wireguard server in combination with your AdGuard Home server.

Enable at least Block newly installed apps by default under Configure → Firewall → Universall firewall rules.

After the first start, it is important to set RethinkDNS as the main and only VPN connection in your Android system.
For that, got to Settings → Network & Internet → VPN → Rethinks “Settings Symbol” → and enable both Always-on VPN and Block connections without VPN.

• KDE-connect only works if the “Do not router Private IPs” option is activated. This only works if you have not activated the option “Block connections without VPN” in your Android settings under “Always-on VPN”.
• Be careful if Rethink asks you again to allow or continue to block certain applications. Especially if it's just a number like 1021. It might be the case that you are allowing a bunch of applications to access the internet. Which you probably want to block! So check the number twice just in case.
• If you need to use an application that involves trackers, simply use the “Isolate Firewall” option. Start the application and only give IPS/domains access to the Internet so that this application can run but keep the trackers still blocked.

Just a simple overview (based on a Moto g34) of how many connections happen before and after setting up RethinkDNS + Firewall.
If you want to check it with your device, just use our "Device Inspections" tutorial.

Before (packets = 775.847) and after (packets = 55.331)