To provide a control method capable of carrying out specification of an abnormal portion in a short time in regard to an information processor, and a control method for the information processor.

In the information processor in an information processing system provided with the information processor having a plurality of first communication ports, a switch having a plurality of second communication ports, and a storage device having a plurality of third communication ports and a plurality of storage volumes, and comprised by communicably connecting the first communication ports and the third communication ports to the second communication ports in a one-to-one correspondence, when a response from the storage device with respect to a first data input/output request by a first channel from the first communication port to the first storage volume is no received within a predetermined time, second and third data input/output requests are respectively sent from the first port on the first channel by second and third channels, an inspection request of the second communication port on the first channel is sent to the switch, and when a response with respect to the second and third input/output requests is not received within the predetermined time and a response with respect to the inspection request is received within the predetermined time, it is determined that the first communication port on the first channel is abnormal.