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.