Secure session border controller system for voip service security

A secure SBC for a safe VoIP(Voice over Internet Protocol) service is provided to ensure call availability in an existing Internet network by providing the VoIP service even in a private IP(Internet Protocol) through an NAT/FW pass function, and to protect equipment within a network by providing a network covert function. A session control module controls session generation, management and data exchange between terminals. The session control module comprises an SIP(Session Initiation Protocol) signaling control server(101), a media relay management server(102) and a media relay worker server(103). A secure module detects and intercepts a malicious call and media. The secure module comprises an SIP detector(104), an SIP filter(105), a media detector(106), a media filter(107) and a policy manager(108). A management module manages element of a system, and reports information about the system. A database(111) stores and manages information so as to assign basic information of detection and interception and to reflect current system resource state information to a secure policy. The management module comprises the followings. An EMS(Element Management System)(109) manages a network of a secure SBC(Session Border Controller) system and manages and operates system elements. An EVTS(Event Server)(110) collects log or state information of each element of the system, and reports the information so as to be reflected to the policy manager.