An information processing system includes a memory, an external storage having a user's area and a system area, and a logging unit collecting communication information in the system. The information processing system further has a unit that receives a network logging activation instruction, and determines whether memory dump information at the point system freezing occurred exists in the system area or not, a unit that copies the network logging file to the system area if the conditions are satisfied, and a unit that writes the communication information stored and maintained in the memory dump information to the copied network logging file.