An image forming apparatus, which comprises a local interface, a network interface, and a relay unit for extracting control data for a peripheral device connected with the local interface from a packet received from the network interface and inputting the extracted control data to a local interface control unit, receives in-abnormality control command data for controlling the connected peripheral device to be performed in case of network disconnection from an information processing apparatus and stores it in a memory, inputs the stored in-abnormality control command data to the local interface control unit in case of detecting an abnormal situation such as the network disconnection from the information processing apparatus, and causes the local interface control unit to control the peripheral device according to the detected abnormal state. Thus, it is possible to achieve intelligent control to the peripheral device even in occurrence of the network disconnection.