JP2003099371A - Apparatus, method and program for preventing spam due to error mail in electronic mail system - Google Patents

Abstract

(57) [Summary] [Problem] To provide a device for preventing spam due to error mail in an electronic mail system for protecting error spam mail relayed by a third party. A message ID collecting unit collects a message ID of a mail transmitted from a mail client. The database 7 stores the message ID or the message ID collected by the message ID collection unit and the return address pair of the sender. The mail transfer unit 11
Send an email message to the appropriate destination. The error mail determining unit 13 determines whether the mail returned as the error mail message is an error mail when an error occurs in the corresponding transmission destination, and transmits the error mail to the mail client if there is no error. If so, the message is transmitted to the message ID comparison unit. Message ID comparison unit 1
5 judges whether there is a corresponding message in the database, and if not, discards the mail.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to electronic mail systems and error mails, and particularly to spam mail prevention.

[0002]

2. Description of the Related Art In an electronic mail system, spam mails (junk mails) have been very frequently transmitted in recent years.
There are many types of spam mails, and e-mail systems are taking measures against them.

The spam mail methods supported by the current electronic mail system are as follows.

A large-capacity mail message-A mail message that does not include its own domain (including subdomain) at the destination-A mail message for relaying purposes (including%, etc. in the address) -Registration as an unauthorized sending domain Sending a large number of mail messages to these messages
The check is performed immediately after receiving the SMTP header in the Protocol or after receiving all the mail messages.

[0005]

However, in the above-mentioned conventional technique, only the method for preventing the case where the mail is directly received from the illegal mail sender is used, and therefore the relay is carried out by the error mail from the third party. There was a problem that we could not defend against the spam mail that was sent.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an apparatus for preventing spam by error mail, a method and a program therefor in an electronic mail system for protecting an error spam mail of a third party relay. The purpose is to do.

[0007]

In order to achieve the above object, an apparatus for preventing spam caused by an error mail in an electronic mail system according to the present invention includes a message ID or a message ID of a mail sent from a mail client.
And a message ID collection unit that collects the reply address of the replyer, a database that stores the message ID collected by the message ID collection unit or the message ID and reply address pair of the sender, and sends the mail message to the corresponding destination. If an error occurs in the sending part and the corresponding recipient, determine whether the mail returned as an error mail message is an error mail, and if it is not an error, send it to the mail client and check if there is an error. For example, it is determined whether or not there is a corresponding message ID or a corresponding message and reply address pair of the sender in the database, and an error mail determination unit that sends the message to the message ID comparison unit. A message ID comparison unit that discards the mail if there is no It is characterized in.

Further, the apparatus for preventing spam caused by error mail in the electronic mail system of the present invention is unique in that it can reversely generate the message ID in the mail header of the mail sent from the mail client based on at least the sender and the sending time. When an error occurs in a means for generating a message ID, a mail transfer unit that sends a mail message to a corresponding destination, and a corresponding destination, it is determined whether the mail returned as an error mail message is an error mail. If there is no error, the message ID is sent to the mail client, and if there is an error, the message ID is sent to the message ID generator, and the message ID is based on the sender and the sending time included in the error message.
Message I included in the error message
Compare with D, if it matches, send it to the mail client,
And a message ID generation unit that discards the mail if they do not match.

Further, the method for preventing spam by error mail in the electronic mail system of the present invention collects the message ID or message ID of the mail sent from the mail client and the sending address of the replyer, and collects the collected message ID or Accumulate the message ID and sender's reply address pair, send the mail message to the corresponding destination, and if an error occurs at the corresponding destination, judge whether the mail returned as an error mail message is an error mail or not. If it is not an error, it is sent to the mail client, and if it is an error, whether or not it matches the accumulated message ID or the pair of the message ID and the reply address and the message ID included in the mail message or the message ID and the reply address pair. If you judge and agree, Send mail to Le client, If they do not match, characterized by discarding a mail.

Further, the method for preventing spam caused by an error mail in the electronic mail system of the present invention is a unique method that can reversely generate the message ID in the mail header of the mail sent from the mail client based on at least the sender and the sending time. Generate a message ID, send a mail message to the corresponding destination, and if an error occurs at the corresponding destination, judge whether the mail returned as an error mail message is an error mail or not If it is an error, the message ID is reversely generated based on the sender and the sending time included in the error message, compared with the message ID included in the error message, and if they match, the message is sent to the mail client. If you do not do it, it is characterized by discarding the email .

A program for preventing spam caused by an error mail in the electronic mail system of the present invention includes a procedure for collecting a message ID of a mail sent from a mail client or a message ID and a sending address of a replyer on a computer. , A procedure for accumulating the collected message ID or the message ID and the reply address pair of the sender, a procedure for transmitting a mail message to a corresponding destination, and an error mail message when an error occurs at the corresponding destination. It is judged whether the returned mail is an error mail, and if it is not an error, it is sent to the mail client, and if it is an error, the accumulated message ID or a pair of the message ID and the reply address and the message ID included in the mail message are sent. Or message I And to determine whether or not they are coincident with the pair of return address, if they match, send an email to the email client, if no match, to execute the steps abandon the message.

Further, a program for preventing spam due to an error mail in the electronic mail system of the present invention is configured such that a computer, based on at least a sender and a sending time of a message ID in a mail header of a mail sent from a mail client. The procedure to generate a unique message ID that can be generated backward, the procedure to send a mail message to the corresponding recipient, and if an error occurs to the corresponding recipient, is the email returned as an error email message an error email? If it is not an error, it is sent to the mail client. If it is an error, a message ID is reversely generated based on the sender and the sending time included in the error message, and it is compared with the message ID included in the error message. If it matches, send it to your email client If there is no match to perform the procedure abandon the message.

According to the present invention, it is possible to judge whether or not the mail returned as the error message is sent by accumulating the information at the time of sending.

Information such as the message ID at the time of sending can be stored by making it possible to compare the message ID at the time of sending with the message ID uniquely created by reversely generating the message ID included in the error message. It can be judged without.

Further, it is a mail message sent by including a part for judging an error mail, extracting message ID information at the time of sending from the error message returned as an error, and comparing it with the message ID accumulated at the time of sending. You can judge.

Further, the message ID at the time of transmission is extracted from the error message returned as the error, and the message I generated from the original transmission information included in the error message.
By comparing with D, it is not necessary to store information such as the message ID at the time of transmission.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below.

FIG. 1 is a block diagram showing an embodiment of the present invention. As shown in the figure, the mail system 1 is connected between the Internet 3 and the mail client 5. Further, the mail system 1 is connected to the database 7. The mail system 1 includes a message ID acquisition unit 9, a mail transfer unit 11, an error mail determination unit 13, and a message ID comparison unit 15. The message ID collection unit 9 collects the message ID or the message ID and the sender's transmission address from the mail transmitted from the mail client 5, and collects the collected message I.
D or this message ID and reply address are paired and stored in the database. The mail transfer unit 11 sends the mail sent from the message ID collection unit 9 to the Internet 3
Send to the destination via. The error mail judgment unit 13 judges whether or not the mail received via the mail transfer unit 11 has an error. The message ID comparison unit 15 is the message ID of the mail received from the error mail determination unit 13.
Alternatively, the message ID reply address sending data is compared with the message ID or the message ID stored in the database 7 and the reply address of the reply person, and if there is a matching message ID in the database, the mail is sent to the mail client 5. , If there is no match,
Discard the email.

The operation of the spam prevention device in the electronic mail system of the present invention configured as above will be described.

(1) A mail is sent from the mail client 5 to a destination on the Internet 3.

(2) Next, the message ID collecting unit 9 collects a message ID (or a pair of message ID and reply address) that is unique worldwide, and stores it in the database 7.

(3) Next, the message ID collection unit 9 sends a mail message to the mail transfer unit 11.

(4) Then, the mail message is transmitted to the corresponding destination.

(5) When an error (for example, the user is unknown, etc.) occurs in the corresponding transmission destination, it is returned to the transmitted mail system as an error message.

(6) The mail transfer unit 11 sends a mail message to the error mail judgment unit 13.

(7) In the error mail judging section 13,
Determine if there is an error. As for the determination of this error, as shown in FIG. 2, it is determined in step S1 whether or not it is a postmaster. That is, it is determined whether or not it is sent from the destination of the postmaster (usually the mail administrator).
If it is determined in step S1 that the subject is a postmaster, then in step S3, it is determined whether or not there is an error in the subject (title). If the subject has an error, it is determined to be an error.

When the error mail judging section 13 judges that there is an error, it is sent to the message ID comparing section 15. If there is no error, it is sent to the mail client 5 (actually, the mailbox) as it is.

(8) The message ID comparison unit 15 checks whether the corresponding message ID or message ID and the reply sender's sending address exist from the database 7 collected and accumulated at the time of sending, and if there is, the mail client. Send to. If there is no corresponding message ID, it is judged as spam mail and the processing of the mail message is interrupted (discarded).

The actual operation is effective in the following configuration. This will be described below with reference to FIG.

(1) Unauthorized mail sender 17 is test@ccc.c
In order to attack the mail client 19 having the address of o.jp, hoge@aaa.co. against multiple third party mail systems (here, aaa.co.jp, bbb.co.jp). jp,
Send an email to an unauthorized addressee such as hoge@bbb.co.jp. At this time, test@ccc.co.j is used as the From address or Return-Path used as the reply address at the time of error.
Specify p (2) Since it is an invalid address in the third party mail system,
An error mail (User unknown mail) is returned to the From address or return-Path address.

(3) Since the message ID is not in the transmission history on the mail system of the present invention, this error mail is judged to be invalid and is discarded.

FIG. 4 is a block diagram showing another embodiment of the present invention. The same parts as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. As shown in the figure, the mail system 21 has a message ID creation unit 23 and a message ID creation unit 25. Message ID creation unit 23
Calculates a unique message ID by using, for example, a hash function based on the sender and the transmission time. On the other hand, the message ID generation unit 25 reversely generates a message ID using a hash function based on the sender and the transmission time.

The operation of the embodiment of FIG. 4 configured as described above will be described.

(1) A mail is sent from the mail client 5 to a destination on the Internet 3.

(2) The message creating unit 23 creates a unique message ID by performing an operation using, for example, a hash function based on the sender and the sending time of the mail.

(3) A mail message is sent from the message ID creating section 23 to the mail transfer section 11.

(4) Send the mail message to the corresponding destination.

(5) When an error (user unknown etc.) occurs in the corresponding transmission destination, it is returned as a 21 error mail message to the transmitted mail system.

(6) The mail transfer section 11 sends a mail message to the error mail determination section 13.

(7) The message ID generation unit 25 displays the mail message judged by the error mail judgment unit 13 as an error.
Send to. If there is no error, send it to the client (actually, mailbox) as it is.

(8) The message ID generation unit 25 inversely generates a message ID using a hash function based on the sender and the transmission time included in the mail message and compares it with the message ID included in the mail message.
If they match, the mail message is sent to the mail client 5
Send to. If they do not match, it is judged as spam mail,
Suspends (discards) the processing of mail messages.

As described above, according to the configuration shown in FIG. 4, the database 7 becomes unnecessary.

The present invention is not limited to the above embodiment. For example, in the example of FIG. 4, a unique message ID is created by performing an operation using a hash function based on the sender and the sending time, but the message ID is created not only by the hash function but also by another algorithm. May be.

[0044]

According to the present invention, it is possible to judge whether a mail returned as an error message has been sent or not by accumulating information at the time of sending. Also,
By making it possible to compare the message ID at the time of sending with the message ID uniquely created by reversely generating the message ID included in the error message, it is possible to judge without accumulating information such as the message ID at the time of sending. You can

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a spam prevention device for error mails in an electronic mail system of the present invention.

FIG. 2 is a flowchart showing a process of an error mail judgment unit.

FIG. 3 is an explanatory diagram showing an actual example for showing the effect of the present invention.

FIG. 4 is a block diagram showing another embodiment of the present invention.

[Explanation of symbols]

1 ... Mail system 3 ... Internet 5 ... Mail client 7 ... Database 9 ... Message ID collection unit 11 ... Email forwarding section 13 ... Error mail judgment section 15 ... Message ID comparison unit 17: Incorrect email sender 19 ... Mail client 21 ... Mail system 23 ... Message ID creation unit 25 ... Message ID generation unit

Claims (6)

[Claims] 1. A message ID collecting unit that collects a message ID or message ID of a mail sent from a mail client and a sending address of a replyer, and a message ID or message ID collected by the message ID collecting unit and a sender. Database that stores the reply address pairs of, the mail transfer unit that sends the mail message to the corresponding destination, and if an error occurs at the corresponding destination, whether the mail returned as the error mail message is an error mail or not. If there is no error, it is sent to the mail client, and if there is an error, it is sent to the message ID comparison unit. An error mail judgment unit, and the corresponding message ID in the database or the corresponding message ID and the sender's reply address pair If there is A spam ID prevention device for an error mail in an electronic mail system, comprising: a message ID comparing unit that sends a mail to a mail client and discards the mail if it does not exist. 2. A means for generating a message ID in a mail header of a mail sent from a mail client based on at least a sender and a sending time, and a mail transfer section for sending a mail message to a corresponding destination. When an error occurs in the recipient, determine whether the mail returned as an error mail message is an error mail. If it is not an error, send it to the mail client. If it is an error, send it to the message ID generator. A message ID is reversely generated based on the sender and the transmission time included in the error message and compared with the message ID included in the error message. If they match, the message is sent to the mail client, and if they do not match, the mail is sent. And a message ID generation unit that discards Spam prevention device according to the error mail in the e-mail system. 3. A message ID or message ID of a mail sent from a mail client and a sender's reply address are collected, and the collected message ID or message ID and sender's reply address pair are accumulated, and applicable. If you send an email message to the recipient and an error occurs in the corresponding recipient, determine whether the email returned as an error email message is an error email, and if it is not an error, send it to the email client. For example, it is judged whether or not the accumulated message ID or the pair of the message ID and the reply address matches the message ID or the pair of the message ID and the reply address included in the mail message.
A method for preventing spam caused by an error mail in an electronic mail system, which is characterized by sending mail to a mail client and discarding the mail if they do not match. 4. The message ID in the mail header of the mail sent from the mail client is generated based on at least the sender and the sending time, the mail message is sent to the corresponding destination, and the error is sent to the corresponding destination. When it occurs, it is judged whether the email returned as an error email message is an error email, and if it is not an error, it is sent to the email client. If it is an error, the message ID is based on the sender and the sending time included in the error message. Is reversely generated, is compared with the message ID included in the error message, and if they match, the mail is sent to the mail client, and if they do not match, the mail is discarded, and the method for preventing spam by error mail in an electronic mail system. 5. A procedure for collecting, on a computer, a message ID or message ID of a mail sent from a mail client and a sender's sending address, and the collected message ID or message ID and sender's reply address pair. Accumulation procedure, procedure to send an email message to the corresponding destination, and if an error occurs at the corresponding destination, determine whether the email returned as an error email message is an error email. If it is an error, it is judged whether or not the accumulated message ID or the pair of the message ID and the reply address matches the message ID or the pair of the message ID and the reply address included in the mail message. if,
A program to prevent spam caused by error mail in an e-mail system to execute the procedure of sending an e-mail to an e-mail client and discarding the e-mail if they do not match. 6. A procedure of generating a message ID in a mail header of a mail sent from a mail client on a computer based on at least a sender and a sending time, and a step of sending a mail message to a corresponding destination, If an error occurs in the recipient, determine whether the email returned as an error email message is an error email, and if it is not an error, send it to the email client, and if it is an error, send it to the sender and the sender included in the error message. An electronic procedure for executing a procedure of reversely generating a message ID based on the transmission time, comparing with the message ID included in the error message, transmitting to the mail client if they match, and discarding the mail if they do not match. Program to prevent spam due to error mail in mail system Beam.