A management computer, which allocates ports to an information processing system, including a host computer and a storage subsystem, operates to group plural ports, plural logic devices, and the host computers for each storage domain that constitutes a management unit. In the case in which a discovery request for the logic devices is received from a host computer, a storage domain to which the host computer, which has sent the discovery request, and the logic devices, for which the discovery is requested, are specified out of the storage domains in which the plural ports, the plural logic devices, and the host computers are grouped. Then, the ports, which belong to the specified storage domain, are selected, and the selected ports are allocated to the logic devices.