It is necessary to control security management consistently and respond to an intrusion automatically in order to use the network securely in the single administrative domain. This paper presents a Shadowing Mechanism supporting a dynamic extension of security scheme and proposes an ARTEMIS(Advanced Realtime Emergency Management and Intruder Identification System), which is designed and implemented based on the suggested technique. It is possible for security management system developed on the basis of the Shadowing Mechanism to make all network components working under the same security scheme. It enhances the accuracy of intrusion tracing and automatic response through dynamic extension of space and time for security management.