ILLEGAL MAIL DETERMINING DEVICE AND PROGRAM

To determine whether or not a received mail is illegal by only a check on the receiving side without providing a special mechanism on the transmitting side or a relaying network.SOLUTION: Provided is an illegal mail determining device including illegal mail control means which, when it is determined that a received mail is an illegal mail by illegal mail determination means that refers to a history database for storing a transmission history that is a history of mails transmitted to the outside and a reception history that is a history of mails received from the outside, compares either the address group of the transmission history or the address group of the reception history with the address group of the received mails, or both the address group of the transmission history and the address group of the reception history with the address group of the received mails, and thereby determines whether or not the received mail is an illegal mail, executes a process that corresponds to the event that the received mail is determined to be the illegal mail.SELECTED DRAWING: Figure 13 【課題】送信側や中継ネットワークにおいて、特別な仕組みを備えることなく、受信側でのチェックのみで受信メールが不正か否かの判定を行う。【解決手段】不正メール判定装置において、外部へ送信されたメールの履歴である送信履歴と、外部から受信したメールの履歴である受信履歴とを格納する履歴データベースを参照し、前記送信履歴のアドレス群と前記受信履歴のアドレス群のうちのいずれかのアドレス群と前記受信メールのアドレス群とを比較する、又は前記送信履歴のアドレス群と前記受信履歴のアドレス群の両方のアドレス群と前記受信メールのアドレス群とを比較することにより、前記受信メールが不正メールか否かを判定する不正メール判定手段により、前記受信メールが不正メールであると判定された場合に、当該受信メールが不正メールであると判定されたことに応じた処理を実行する不正メール制御手段とを備える。【選択図】図１３