The image processing apparatus performs a communication process targeting an external apparatus via a network. When performing a communication process, the image processing apparatus determines whether or not the external apparatus which is a target of the communication process is registered in a destination list in which apparatuses corresponding to a predetermined condition are registered. In accordance with the timeout period determined based on the determination result, the image processing apparatus determines that a timeout has occurred in the communication process. The image processing apparatus updates the destination list according to the determination result of the occurrence of the timeout and the determination result as to whether or not the external apparatus is registered in the destination list. Thereby, it is possible to provide an image processing apparatus capable of quickly executing communication process because the transmission/reception buffer is less likely to run out.