An information processing device includes: a memory; and at least one processor coupled to the memory. The processor performs operations. The operations include: extracting a transmission source of communication from communication data received by a predetermined device, and generating first data that include the transmission source and a time associated with communication and included in the communication data; and totaling a first frequency of reception of the communication data for the each transmission source, based on the first data, in each of a first period and a second period that includes the first period and is longer than the first period.