Patent ID: 8209529

Claim:
An authentication system including a network line concentrator and an authentication server for authenticating a terminal equipment accommodated in said network line concentrator, wherein said network line concentrator comprises a unit for restricting transfer of a frame except an authentication request frame transmitted from any other node except an authenticated terminal equipment authenticated by said authentication server to an inside and an outside of a network including said authentication server, wherein said unit for restricting transfer of a frame enables the terminal equipment to access only the authentication server via the authentication request frame before authentication, wherein said authentication server receives an authentication request frame transmitted by the terminal equipment using a dispensed IP address as a sender address and authenticates the terminal equipment, wherein, upon completion of authentication, said authentication server informs a registration information database of an authentication hub of communication permission for the terminal equipment, wherein, when a frame receiving circuit of said authentication hub receives a frame transmitted from the terminal equipment: said authentication hub refers to the registration information database on the basis of sender information of the frame to determine whether: i) transmission, ii) rewriting-and-transmission, or iii) discarding are to be performed for the frame, and said authentication hub sends the frame to a transmission buffer when said authentication hub has determined that the transmission or the rewriting-and-transmission are to be performed for the frame.