NetGuard is a free, open-source firewall for Android phones and tablets that provides users with a simple way to block internet access. Android does not allow VPN services to be chained, so the app uses the Android VPN service to route all internet traffic through itself. NetGuard can be used without root access, although it also works on rooted devices. Activating NetGuard To activate the firewall, I enabled NetGuard using the switch in the action … More → The post Product showcase: NetGuard open-source firewall for Android appeared first on Help Net Security .