US Patent 7127543 Access control apparatus and access control method

In an access control system, accesses are controlled which are received from not only the same communication network, but also either one or a plurality of other communication networks. In this access control system, a channel processor of a storage control system accepts a log-in request containing a target IP address from a target host apparatus, and compares this target IP address with the own IP address stored in an iSCSI port. Based upon a comparison result, the channel processor judges a network relative logical distance of a target network with respect to a communication network containing the storage control system as to the target network containing a target host apparatus. Then, the channel processor permits an access of a permission access type corresponding to the judged network relative logical distance with respect to a target upper grade apparatus.