How to block access to the Internet if the proxy has fallen on Android?

Question

Android

I use Proxy Droid on android to raise the proxy.
But there is one caveat, when the system starts, when Proxy Droid is not yet running, the IP address remains the same.
By what means can you disable access to the Internet if the proxy is not running?
Maybe some software like iptables

Answer 1

AFWall+