Image processing apparatus and method of communicating with an external apparatus

An image processing apparatus capable of fax communication and a method of controlling the image processing apparatus are described. The image processing apparatus has a user interface capable of accepting from a user, in advance of receiving by a network interface a shutdown request, a setting of whether or not to perform shutdown processing based on the received shutdown request when the image processing apparatus is in a state of being connected to a fax line and when fax communication is possible. The image processing apparatus executes, in accordance with the setting accepted in advance from the user by the user interface, the shutdown processing of the image processing apparatus based on the shutdown request received from the external apparatus.