A receiver receives e-mails. In the case where an address of an e-mail is a user's
e-mail address which is managed by another e-mail server device, a transfer unit
transfers the e-mail to the another e-mail server device. In the case where an
address of an e-mail is a user's e-mail address which is managed by an e-mail server
device including an inquiry unit, this inquiry unit inquires of the corresponding
user whether to accept the e-mail to be delivered from its e-mail addresser. In
the case where the user does not accept the e-mail to be delivered, a notification
unit sends a message for informing the addresser that there is no user having a
public e-mail address. In the case where the conditions for delivering an e-mail
are all satisfied, a delivery unit delivers the e-mail to a user having a public
e-mail address.