Remote maintenance system, e-mail connection confirmation method, mail connection confirmation program and e-mail transmission environment diagnostic program

摘要

When a fault is detected by a surveillance agent (16) mounted in a user device (12), fault information is reported to a maintenance center device (10) by electronic mail through the internet (14). The user device is provided with a connect confirmation unit (28) to prepare and transmit connect confirmationmails of a plurality of patterns different in mail content, and the maintenance center device is provided with a diagnosis unit (42), which diagnoses a mail transmission environment of the user device (12) from the reception result of one or a plurality of connect confirmation mails received within a fixed period of time and transmits a diagnosis result to the user device by electronic mail.