An image forming apparatus includes a memory that stores a program, and a processor that executes the program. When a USB control module receives PDL data from a second host computer via a USB interface, the PDL data is transmitted to a print processing module, and when a TCP/IP processing module receives first IPP print data from a first host computer, the first IPP print data is transmitted to a Web server module. When the USB control module receives second IPP print data from the second host computer, the second IPP print data is transmitted to the TCP/IP processing module by loopback and the second IPP print data is transmitted to the Web server module, and when the Web server module receives the first or second IPP print data from the TCP/IP processing module, the first or second IPP print data is transmitted to the print processing module.