Computer security is considered important due to the side effect generated from the expansion of computer network and rapid increase of use of computers. A attack of intruders using a vulnerability of operating system, protocol and application programs. And so, The attack methods is to be high technology and professional. Thus It must be necessity that we necessary a solution to structure, management for framework of information technology. This paper develope intrusion detecting system for separating intruders form critical system and design IDS model and implementation of it