A high performance packet-filtering engine with source code for developing firewall. EasySec Firewall SDK with source code is a professional software kit for developing network firewall, sniffer or analyzer applications for Microsoft Windows. Simple APIs of EasySec Firewall SDK include powerful functions: double layer packet filter (application layer and kernel layer) can manage and control data packets of all kinds network protocols quickly and correctly. Application auditing avoids back door program leaking sensitive information, and generates application filter rule intelligently. Particular filter rules of net neighborhood can manage and control the shared resource, prevent information leaking from local network; lots kinds of filter rules can achieve your requirement for managing network information.