Patent ID: 7685243

Claim:
A mail server comprising: an address-change accepting section which accepts a change of a mail address of a user device; an address-history management section which manages history of the mail addresses of the user device; a mail receiving section which receives a mail to a destination device from a transmission origin device; a mail transmitting section which attaches history of mail addresses of the transmission origin device to the received mail and transmits the mail having the history attached thereto to the destination device and wherein: the address-history management section manages the history of the mail addresses of the user device including a first mail address and all the mail addresses changed thereafter of the user device; and the mail transmitting section attaches, to a mail to be transmitted to the destination device, all the history of mail addresses of the transmission origin device of the mail managed by the address-history management section and transmits the mail having the history attached thereto to the destination device.