Network Security is one of the most critical issues of establishments like universities, govermental and private institutions which have significant role on development and security of a state. These establishments use internet to share and keep official information, and to make their institutive operations. A cyber attack that targetted such establishments networks may cause a great loss. Therefore, networks of these establishments ought to protect on a high level security. In this paper, a system is offered which is able to investigate networks of institutions and ranking their network by predefined parameters. Moreover Network Security Simulator is offered to implement the system.