Here you must use the Linux part of Android, and #netstat -a (or -g), filter the output, into Listening, Established, Various Iowait and Closed. The problem is that Microsoft keeps connections "Alive" - Lingering, to allow others to connect. This is spyware and viruses.
First, users can actually see who is spying, as opposed to what resources you want to use.
You can kill these with -9 and the file system will remove them.
You can block them by making entries in /etc/hosts / host.alias by entering IP address TAB name, a line with "192.168.31.199 scammers.net" will make it impossible for the scammers.net to track me.
However, block Google sites and pretty close to nothing will work, so you must have an "undo" options, be able to go back, test. Start the line with # will remove the entry. Everything after the # is ignored in definitions.
There's a lot of data in the netstat, and most ports are never used, they should be in LISTEN state but is kept alive, just in case.
There's number of bytes In/out.
The port is linked to PID, launchd holds the name.
You can use the hosts file to manage a local copy of DNS entries. Share this with other users and you have the Bonjour that Apple uses.
Stop here, don't make another VPN service. You can charge for that separately.
