| 摘要 |
PROBLEM TO BE SOLVED: To improve the confirmation that a receiving end already reads in addition to minimally suppressing the improvement of an existing system. SOLUTION: The information made identification information ID, mail opening information which shows unopened state of a mail body MBDY at a caller client, caller information, receiver information, date and time information and heading information correspond to each other is stored and managed as electronic mail management information in a mail box. An electronic mail EML which includes a return mail program RMP that is started so as to return mail opening confirmation and the identification information ID of a mail as a return mail is sent when a sending destination client opens the mail at the time of transmitting the mail. When the decision result of mail opening confirmation from the caller client is acquired from a return mail RM that is subsequently received, identification information ID extracted from the received return mail RM, and the mail opening information of the electronic mail corresponding to the identification information ID is changed into an opened state. |
