SERVER, NETWORK SYSTEM AND MAIL TRANSMISSION METHOD

摘要

PROBLEM TO BE SOLVED: To provide a server, a network system and a mail transmission method by which an electronic mail can securely be delivered to a transmission destination even when the mail address of an individual is changed or the organization or department to which the individual belongs is revised. SOLUTION: A sender terminal 2, a receiver terminal 3, a mail gateway server 4, and a directory server 5 are connected to a network 1. The directory server 5 stores the personal information of a user of the receiver terminal 3 and a personal certificate identifying the user. Upon receipt of a mail with a personal certificate form the sender terminal 2, the mail gateway server 4 retrieves information of the transmission destination stored in the directory server 5 on the basis of the personal certificate attached to the mail and transfers the mail from the sender terminal 2 to the receiver terminal 3 when the retrieval confirms the receiver terminal 3.