Patent ID: 8185961

Claim:
A network system comprising: a client terminal; an administration server; at least one storage device including a plurality of storage units; an authentication server; and a network to connect the client terminal, the administration server, the authentication server, and the storage device to each other, wherein the administration server includes: a control unit that creates a first password that is required for the client terminal to cause a specific one of the storage units to be mounted on, and sends information on the specific storage unit and the first password to the client terminal, and a database that stores therein the first password as a second password in association with a corresponding user identifier; the client terminal includes: a password receiving unit that receives the first password from the administration server, and a request sending unit that sends, to the storage device, a request to access the specific storage unit, the request containing the user identifier and the first password; the storage device includes: a request receiving unit that receives the request from the client terminal, and a first-inquiry sending unit that sends, to the authentication server, a first inquiry containing the user identifier and the first password that are contained in the request; the authentication server includes: a first-inquiry receiving unit that receives the first inquiry from the storage device, and a second-inquiry sending unit that sends, to the administration server, a second inquiry containing the user identifier and the first password that are contained in the first inquiry; the administration server further includes: a second-inquiry receiving unit that receives the second inquiry from the authentication server, and a checking unit that checks whether the user identifier and the first password contained in the second inquiry agree with the second password and the corresponding user identifier stored in the database, and sends a result of check to the authentication server; and the authentication server further includes: a result unit that receives the result of check from the administration server and upon receiving the result of check, sends the result of check to the storage device; the storage device further includes: a check-result receiving unit that receives the result of check from the administration server via the authentication server, and a response sending unit that sends, to the client terminal, a response indicative of any one of approval or disapproval to the request based on the result of check.