Patent ID: 7752289

Claim:
A device authentication system comprising: a first device provided on the client side of a client/server system; and a second device provided on the server side of the client/server system, wherein said first device comprises a registration requesting unit configured to iteratively, at a predetermine time interval, send a request for registering a MAC address specific to the first device in response to a registration requesting operation of a user; said second device comprises a temporary memory configured to temporarily store the MAC address, when a registration request having the same MAC address is received a plurality of times or for one time within a predetermined time after a first confirmation operation of the user is performed; a registration confirmation unit configured to send a registration confirmation to the first device having the MAC address stored in said temporary memory in response to a second confirmation operation of the user; said first device further comprises a registration confirmation responding unit configured to receive said registration confirmation so as to instruct said registration requesting unit to stop the iterative sending, and also to send back a registration confirmation response to the second device which has sent the registration confirmation; said second device further comprises an authentication and registration unit configured to authenticate and register the MAC address which is temporarily stored in said temporary memory in response to a third confirmation operation of the user, which is performed after said registration confirmation response is received, and said second device rejects access from a client corresponding to the first device having a MAC address other than the MAC address which is authenticated and registered in the second device itself, and instructs the server not to respond at all to the client.