Patent ID: 7809001

Claim:
An opened network connection control method, for connecting to an opened network from a closed network, the closed network comprising: terminal units connected to one another in such a way as to be able to exchange data with one another; a central unit which receives a connection request to the opened network from each of the terminal units, and controls connection to the opened network; and a connection control unit which receives an assignment request for a virtual logic identifier from the central unit and assigns the virtual logic identifier to each of the terminal units, the connection control method comprising: storing connection condition information having a keyword indicating an item necessary for ensuring a security level of the terminal unit from which the connection request is received and an update number indicating a process for updating the item; receiving an assignment request from the central unit; acquiring connection history information having the keyword indicating the item installed in each terminal unit and the update number indicating the process which was applied to each terminal unit which corresponds to the assignment request to the opened network; determining whether the acquired connection history information fulfills the connection condition information or not by comparing the update number in the connection history information and the update number in the connection condition information with respect to the keyword; and assigning the virtual logic identifier to the terminal unit corresponding to the assignment request when it is determined that the acquired connection history information fulfills the connection condition information.