Hi, i can do this if target architecture is Windows Vista or newer. In Windows Vista - Base Filtering Engine was introduced, it allows to intercept network packets and pass them through or drop, both inbound and outbound traffic. This solution will allow to switch on and off, without need of enabling/disabling network interface controllers (IP address is not going to be released or renewed when ON/OFF button is pressed). Base Filtering Engine is used by Windows Firewall - my solution will work similarly and will require UAC for the application to run. This will work also on systems with 3rd party firewalls installed like COMODO Firewall. Technologies: Base Filtering Engine (via WinDivert), Lazarus for user interface. Compatibility: Windows Vista, 7, 8, 8.1, 10.