AFWall+
AFWall+ (Android Firewall +) - iptables based firewall for Android
...AFWall+ provides connection logging, blocked traffic notifications, and advanced rule scripting for network monitoring. It also supports IPv4 and IPv6, multi-user environments, and automation through Tasker or Locale. By enforcing network restrictions at the system level, it helps reduce unwanted connections, background data consumption, and potential information leaks.