Together with an image forming apparatus, a method and a control program which can be applied to the image forming apparatus are disclosed in an embodiment of the invention. The image forming apparatus is an image forming apparatus for printing data whose printing has been requested from a client apparatus via a network. The image forming apparatus has: identifying means for identifying a text portion and an attached file with respect to E-mail transmitted from the client apparatus, recognizing means for recognizing control data which can be disclosed in the text portion of the E-mail and control data which can be enclosed in the attached file identified by the identifying means, and control means for controlling a printing process in accordance with a recognition result of the recognizing means showing whether at least either the text portion or the attached file identified by the identifying means includes the control data or not.