SDN firewall system and implementation method

The invention discloses a SDN firewall system and an implementation method, wherein management and control of the system and the method on a firewall are all centralized at a controller, through unified management of the controller on the whole network, more secure and convenient services are provided for a SDN network. In order to separate an intranet from a public network, data packets of the firewall are detected out, and which data packets are going to be captured or released is determined. A user can fill in an own access strategy to determine whether to allow access to some websites or not. A firewall module of such project uses layer 2 forwarding. The system is a SDN firewall system based on an Openflow protocol 1.3, and the system uses a python language to write on a ubuntu system, and runs normally on the ubuntu system; and the system and the method can realize cross-platform transplantation better, and the system has very important application value.