JP5044686B2 - Mail non-delivery judgment device and program - Google Patents

Description

  The present invention relates to a mail non-delivery determination device and program, and in particular, a mail non-delivery determination device for determining non-delivery of a transmitted electronic mail, and a mail non-delivery determination for causing a computer to function as the mail non-delivery determination device. Regarding the program.

  E-mail is now widely used as one of the means for sending and receiving information via the Internet. As an example, in a website that provides a predetermined service to a registered user, as user information If you have registered an email address and need to notify the user, create an email with the notification content and send the registered email address as the destination. Notification to the user is made.

  By the way, for example, in the above aspect, if there is an error in the e-mail address input by the user, there is a disadvantage that the transmitted e-mail does not reach the user. In addition, when the mail server that manages the user's mailbox is temporarily out of order, the sent email is used even if the email address set as the destination is accurate. May not reach the person. For this reason, for example, when registering an e-mail address, an e-mail (test e-mail) with the input e-mail address as the destination is sent for the purpose of confirming the e-mail address, or an e-mail with an important notice is written. If you want to detect e-mails that have already been sent to a registered e-mail address, etc., and the e-mail you sent has not arrived (specifically, it has not arrived at the destination mailbox) Needs exist.

  In relation to the above, Patent Documents 1 to 3 describe whether the MINE (Multipurpose Internet Mail Extensions) type of the received e-mail is a report format (Content-Type is multipart / report), and the report-type is delivery-type. A technique is disclosed in which the status is checked in order and the received mail is determined to be an error mail if applicable.

  Further, in Patent Document 4, in an Internet facsimile apparatus that transmits and receives image information and the like by electronic mail, whether the header part of received mail data includes an [X-mailer:] field, and [From:] of the header part. And a character string registered in the character string list table are sequentially checked, and a received mail is determined to be an error mail when it corresponds.

JP 2003-271527 A JP 2002-204330 A JP 2002-44358 A JP 2001-142802 A

  The technologies described in Patent Documents 1 to 4 determine whether or not the received electronic mail is an error mail. This error mail is sent to a mail server (receiving mail server) that has received an email in which the mailbox in the domain is set as the destination by the destination email address. E-mail that is automatically sent by the receiving mail server when it cannot be stored in the destination mailbox because the mailbox does not exist or the mail server is temporarily out of order It is. For this reason, when an e-mail is sent to an arbitrary destination and then an e-mail is received with the source e-mail address set in the e-mail as the destination, the received e-mail is an error e-mail by applying the above technique. In principle, it is possible to detect the non-delivery of the previously sent e-mail.

  However, the error mail judgment conditions described in Patent Documents 1 to 3 stipulate RFC (Request for Comments), which is an official document of the IETF (Internet Engineering Task Force), technical information, specifications, operational rules, etc. regarding the Internet. On the other hand, the inventors of the present application send error mails that do not comply with the above RFC rules to a large number of mail servers existing on the Internet. We have confirmed that there are many mail servers. Under the above judgment conditions, there are many e-mails (that is, cases where non-delivery cannot be detected) that are not judged as error mails even though they are actually error mails. There is a problem that may occur.

  The error mail determination conditions described in Patent Document 4 are “DEAMON”, “mailer”, “DEAMON”, “mailer”, and “Mailer”, in the [From:] field of the header part of the received mail data transmitted as error mail. Based on the rule of thumb that specific character strings such as "DELIVERY", "SYSTEM", "POST MASTER" are often set, these character strings are registered in the character string list table and used for matching. It is difficult for a wide variety of mail servers to recognize all the character strings set in the above fields of error mail and register them in the table. Even when the technique described in Patent Document 4 is applied, an error actually occurs. There is a possibility that a large number of e-mails that are not determined as error mails despite being mails may occur. Also, even if a wide variety of mail servers can recognize all the character strings set in the above fields of error mail, a mail server that sets a new character string in the above fields of error mail may appear. Considering the above, there is also a problem that regular maintenance of the character string list table is necessary to maintain the error mail determination accuracy.

  The present invention has been made in consideration of the above facts, and an object thereof is to obtain a mail non-delivery determination device and a mail non-delivery determination program that can easily and accurately determine non-delivery of a transmitted electronic mail.

  According to the RFC convention, an error mail transmitted from a mail server has a multipart structure, and an error code is described after a character string “Content-Type: message / delivery-status”. In order to confirm this, the inventors of the present application randomly selected more than 800 mail servers from a huge number of mail servers existing on the Internet, and for each selected mail server, Consider sending emails with destination email addresses set so that error emails are sent from individual mail servers, and analyzing the content of error emails sent from individual mail servers for the emails sent Went. As a result, although many mail servers send error mails that comply with the RFC rules, as described above, error mails that do not comply with the RFC rules, specifically, "Content-Type: message / It was confirmed that there are many mail servers that send error mails that do not contain the "delivery-status" string.

  In addition, the inventors of the present application have responded to an error mail transmitted from a mail server that transmits an error mail that does not comply with the RFC rules (an error mail that does not include the character string “Content-Type: message / delivery-status”). The contents were further analyzed, and a study was conducted to find common features. As a result, the present inventors have found some common features from the above error mail. Among them, when an e-mail whose body is described in text format is sent to the mail server, it is sent from the mail server. The feature that the text included in the error mail is not changed from the text format (if the user creates and sends a reply e-mail, the text may be changed from the text format to another format such as HTML format) ) And the error mail sent from the mail server includes the information of the email sent to the mail server, which is common to most error mails, and the received email is The determination as to whether or not the above two features are provided is based on the table as in the [From:] field determination in the technique described in Patent Document 4. It has been conceived that complicated operations or processing such as collection of character strings for registration in the database and periodic table update are unnecessary.

Based on the above, the mail non-delivery determination device according to the first aspect of the present invention calculates a hash value by inputting information different from each e-mail into a hash function with a single part structure and a body text described in a text format. A predetermined e-mail to which the e-mail specific hash obtained in step 1 is added is set to the e-mail transmission unit that transmits an arbitrary e-mail address as a destination, and the predetermined e-mail transmitted by the e-mail transmission unit When an e-mail having a transmission source e-mail address as a transmission destination is received, first determination means for determining whether or not the received e-mail has a multi-part structure, and the received e-mail by the first determination means If the mail is determined to have a multi-part structure, determine whether the received email contains the string "message / delivery-status" And when the second determination means determines that the received e-mail does not contain the character string “message / delivery-status”, the received e-mail information includes A third determination unit that determines whether or not the contained body has been changed from the text format; and the received message when the third determination unit determines that the body has not been changed from the text format. Fourth determination means for determining whether or not the information of the predetermined e-mail including the mail specific hash added to the predetermined e-mail corresponding to the received e-mail is included in the information of the e-mail And the first determination means determines that the received electronic mail has a multipart structure, and the second determination means adds a character string “message / delive” to the received electronic mail. ry-status "is not included, and the third determination unit determines that the body has not been changed from the text format, and the fourth determination unit determines whether the received electronic mail When it is determined that the information includes information on the predetermined email including the mail specific hash added to the predetermined email corresponding to the received email, the received electronic Output means for outputting a determination result that a predetermined electronic mail corresponding to the mail did not reach the transmission destination.

According to the first aspect of the present invention, the mail obtained by calculating the hash value by inputting the different information for each e-mail to the hash function by the mail transmitting means with the body part described in the text format in the single part structure. A predetermined e-mail to which a specific hash is added is transmitted with an arbitrary e-mail address as a transmission destination. Here, when an e-mail having a transmission source e-mail address set as a predetermined e-mail is received, the first determination means determines whether or not the received e-mail has a multi-part structure. When the received e-mail is determined to have a multipart structure by the first determining unit, the second determining unit determines whether the received e-mail includes the character string “message / delivery-status”. Determine whether. As described above, the first determination unit and the second determination unit determine whether or not the received electronic mail has an error mail characteristic conforming to the RFC rules.

In addition, when the second determination unit determines that the received e-mail does not include the character string “message / delivery-status”, the third determination unit includes the received e-mail information. If the third determination means determines that the body included in the received e-mail information has not been changed from the text format, the first determination is made. 4 determination means determines whether or not the received e-mail information includes predetermined e-mail information including a mail specific hash added to the predetermined e-mail corresponding to the received e-mail. . As described above, the third determination unit and the fourth determination unit do not include some of the characteristics of the error mail in which the received e-mail conforms to the RFC rules (the character string “message / delivery-status” is included). If it is not, it is determined whether or not another feature of the error mail found by the present inventors is provided.

According to the first aspect of the present invention, the received electronic mail is determined to have a multi-part structure by the first determining means, and the character string “message / delivery-status” is added to the received electronic mail by the second determining means. "Is not included, and the third determination means determines that the body has not been changed from the text format, and the fourth determination means adds the received electronic information to the received e-mail information. The predetermined e-mail corresponding to the received e-mail by the output means when it is determined that the information of the predetermined e-mail including the mail specific hash added to the predetermined e-mail corresponding to the e-mail is included Outputs the result of the determination that did not reach the destination. As described above, the characteristics determined by the third determination means and the fourth determination means are characteristics common to most error mails and have high determination accuracy. Further, the determination by the third determination means and the fourth determination means does not require complicated work or processing such as collection of character strings for registration in the table or periodic table update. Therefore, according to the first aspect of the present invention, it is possible to easily and accurately determine the non-delivery of the transmitted electronic mail.

  By the way, in the invention described in claim 1, for example, as described in claim 2, the output means includes the character string “message / delivery-status” in the received electronic mail by the second determination means. If it is determined that the predetermined e-mail corresponding to the received e-mail has not arrived at the transmission destination, it is preferable to output a determination result. When the second determination means determines the received e-mail as described above, the received e-mail is an error mail complying with the RFC rules, and a predetermined e-mail corresponding to the received e-mail is received. It can be determined that it has not reached the destination. As a result, when it is possible to determine that the received e-mail is an undeliverable e-mail based on the fact that the received e-mail is an error mail complying with the RFC rules, this can be output as a determination result.

  When the body included in the e-mail information is changed from the text format to the HTML format, the character string “text / html” is added to the e-mail information. Therefore, in the invention described in claim 1, specifically, the determination by the third determination means is performed by adding the character string “text / html” to the received e-mail information as described in claim 3, for example. Search whether it is included or not, and if the text "text / html" is not extracted by the search, determine that the text included in the received email information has not been changed from the text format Can be done.

  By the way, there is a possibility that a file is attached to the received electronic mail, but it has been confirmed by the inventors of the present application that a file is rarely added to an error mail by the mail server. Considering this, in the invention described in claim 1, for example, as described in claim 4, the third determining means also determines whether or not a file is attached to the received electronic mail, and the fourth determining means Is determined when the third determination means determines that the text included in the received e-mail information has not been changed from the text format, and that the received e-mail does not have a file attached thereto. Preferably, it is configured to determine whether or not the predetermined electronic mail information is included. Thereby, it is possible to further improve the determination accuracy with respect to non-delivery of the transmitted electronic mail.

  Further, in the invention described in claim 1, the determination by the fourth determining means is, specifically, as described in claim 5, for example, as described in claim 5, a part of the information on the transmitted predetermined e-mail or Information that is configured to store all in the storage unit, and that the fourth determination unit stores information in a part in which the original e-mail information is set in the received e-mail information is stored in the storage unit By checking the predetermined e-mail corresponding to the received e-mail, and whether or not the corresponding e-mail information is included in the received e-mail information. This can be realized by making a determination. Thereby, even if the mail transmitting device transmits a large number of e-mails as a predetermined e-mail and receives a corresponding large number of e-mails, It is possible to reliably determine whether or not information of electronic mail is included.

Further, in the invention according to claim 5, the storage means may store all the information of the predetermined e-mail and use it for collation with the received e-mail information. The information may be configured to determine whether or not all of the corresponding predetermined e-mail information is included. For example, as described in claim 6, the e-mail transmission unit may be configured to determine the predetermined e-mail. A mail specific hash is added to the body of the message and transmitted, and the mail specific hash , the transmission date and time, and the destination e-mail address are associated with each other and stored in the storage unit as a part of predetermined e-mail information. and, a fourth determination means, a portion of which the original e-mail information of the received e-mail information is set, mail specific hash stored in association in the storage means By determining whether or not the transmission date and time and the destination e-mail address are all included, it is possible to determine a predetermined e-mail corresponding to the received e-mail and to correspond to the received e-mail information. It is preferable to determine whether or not predetermined e-mail information is included. As a result, the storage capacity of the storage unit can be reduced, and the size of information collated by the fourth determination unit can be reduced, so that the determination by the fourth determination unit can be speeded up.

The mail non-delivery determination program according to the invention described in claim 7 calculates a hash value by inputting a computer into a hash function with information that is different in each e-mail, with the body being described in a text format in a single part structure. A predetermined e-mail to which the e-mail specific hash obtained in step 1 is added, a mail transmission unit that transmits an arbitrary e-mail address as a transmission destination, a transmission set in the predetermined e-mail transmitted by the e-mail transmission unit When an e-mail with the original e-mail address as a destination is received, first determination means for determining whether or not the received e-mail has a multi-part structure, and the e-mail received by the first determination means is Whether or not the string "message / delivery-status" is included in the received e-mail when the multi-part structure is determined A second determination unit that determines whether the character string “message / delivery-status” is not included in the received electronic mail by the second determination unit; The third determination means for determining whether the body included in the text format has not been changed from the text format, and the received when the third determination means determines that the body has not been changed from the text format Fourth determination means for determining whether or not the information of the predetermined e-mail including the mail specific hash added to the predetermined e-mail corresponding to the received e-mail is included in the information of the e-mail The received electronic mail is determined to have a multi-part structure by the first determining means, and a character string “messa” is added to the received electronic mail by the second determining means. ge / delivery-status "is not included, and the third determining unit determines that the body has not been changed from the text format, and the fourth determining unit receives the received electronic The mail information is received when it is determined that the information on the predetermined email includes the mail specific hash added to the predetermined email corresponding to the received email. It is made to function as an output means for outputting a determination result that a predetermined electronic mail corresponding to the electronic mail has not arrived at the transmission destination.

  According to a seventh aspect of the present invention, there is provided a mail non-delivery determination program for causing a computer to function as the mail transmission means, first determination means, second determination means, third determination means, fourth determination means, and output means. Therefore, when the computer executes the mail non-delivery determination program according to the invention described in claim 7, the computer functions as the mail non-delivery determination device according to claim 1. Similar to the described invention, non-delivery of the transmitted electronic mail can be determined easily and with high accuracy.

As described above, the present invention adds a mail specific hash obtained by calculating the hash value by inputting the different information for each e-mail into the hash function, with the body text described in the single part structure in the text format. When a predetermined e-mail is transmitted with an arbitrary e-mail address as a transmission destination, and an e-mail with the transmission source e-mail address set as the predetermined e-mail is received, the received e-mail If the received e-mail has a multi-part structure, it is determined whether or not the character string "message / delivery-status" is included in the received e-mail. If the column “message / delivery-status” is not included, it is determined whether the body included in the information of the received email has been changed from the text format. If not changed from strike format, determines whether or not included said predetermined electronic mail information including email specific hash obtained by adding a predetermined electronic mail corresponding to the information of the received electronic mail, the received e The predetermined e-mail corresponding to the received e-mail did not reach the destination when the predetermined e-mail information including the mail specific hash added to the predetermined e-mail corresponding to the e-mail information is included. Since the determination result is output, it is possible to easily and accurately determine the non-delivery of the transmitted electronic mail.

It is a block diagram which shows schematic structure of the computer system which concerns on this embodiment. It is a flowchart which shows the content of the test mail transmission process. It is a flowchart which shows the content of mail non-delivery determination processing. It is an image figure which shows an example of an error mail.

  Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a computer system 10 according to the present embodiment. The computer system 10 includes a website management system 12. The website management system 12 is a system that manages a specific website, and is configured such that a web server 14, an application server 16, a mail transmission / reception server 18, and a mail server 20 are connected to each other via an intranet (not shown). Yes.

  Among the servers of the website management system 12, the web server 14 and the mail server 20 are connected to the Internet 22. FIG. 1 shows only the mail server 24 among a large number of servers connected to the Internet 22. The mail server 24 manages the mailbox of its own domain, and performs processing such as delivery of e-mail on the Internet 22 and storing of e-mail delivered to its own domain in the corresponding mailbox. Also connected to the Internet 22 are a large number of client terminals 26 each comprising a personal computer (PC), a PDA (Personal Digital Assistance) having a function of accessing the Internet 22, and a mobile terminal such as a mobile phone. .

  The web server 14, the application server 16, the mail transmission / reception server 18 and the mail server 20 have the same configuration. The configuration of the mail transmission / reception server 18 will be described as an example. The mail transmission / reception server 18 includes a CPU 18A, a RAM, and the like. A memory 18B, an HDD (Hard Disk Drive) 18C, and a network interface (I / F) unit 18D are provided, and a display 30, a keyboard 32, and a mouse 34 are connected to each other. The HDD 18C of the mail transmission / reception server 18 is provided with a storage area used as a reception folder, stores a transmission mail information DB (database), and a test mail for the CPU 18A to perform a test mail transmission process described later. A transmission program and a mail non-delivery determination program for determining mail non-delivery are installed. The mail non-delivery determination program corresponds to the mail non-delivery determination program according to the present invention. When the CPU 18A executes this program, the mail transmission / reception server 18 functions as the mail non-delivery determination device according to the present invention. . The mail transmission / reception server 18 also functions as mail transmission means according to claim 1 or the like when the CPU 18A executes a test mail transmission program.

  Next, the operation of this embodiment will be described. Each time a specific website is accessed from an arbitrary client terminal 26 via the Internet 22, the web server 14 distributes the information on the web page in the specific website to the client terminal 26 that is the access source via the Internet 22. I do. The specific website operated by the website management system 12 according to the present embodiment is a website that provides a predetermined service to an authorized user who has registered user information in advance, and is a web server. 14, when a specific website is accessed from an arbitrary client terminal 26, first, information on a web page that requests a user who operates the client terminal 26 to perform a login operation or a user information input operation. Is distributed to the client terminal 26 of the access source.

  The HDD of the application server 16 stores a user information DB in which authentication information such as a user ID and a password and user information including a name, an address, and an e-mail address are registered for each authorized user. When the user performs a login operation to input authentication information such as a user ID and a password and receives the authentication information input by the user from the client terminal 26, the web server 14 uses the received authentication information as an application. Transfer to server 16 As a result, the application server 16 determines whether or not the transferred authentication information is registered in the user information DB, thereby determining whether or not the user who performed the login operation is an authorized user. Person authentication processing is performed, and the result is notified to the web server 14. If it is determined by the user authentication process that the user who performed the login operation is an authorized user, the web server 14 specifies the request in response to a request from the client terminal 26 operated by the authorized user. The application server 16 performs a process of distributing information on an arbitrary web page in the website of the client to the client terminal 26, and the application server 16 provides a process of providing a predetermined service (for example, a specific website performs online execution of a predetermined financial transaction). If the website provides a service that can be instructed in step (a), a predetermined financial transaction requested by a legitimate user is executed via the client terminal 26).

  On the other hand, when a user information registration operation is performed by a user operating the client terminal 26, the web server 14 is a web page for inputting user information such as name, address, password, and e-mail address. Is delivered to the client terminal 26. Then, a user information input operation for inputting user information such as name, address, password, and e-mail address is performed by the user via the web page, and the user information input by the user is stored in the client terminal 26. The web server 14 transfers the received user information to the application server 16, and the application server 16 registers the user information transferred from the web server 14 in the user information DB.

  By the way, the e-mail address in the above-described user information is used when the website management system 12 needs to make a certain notification to a specific user. That is, when it becomes necessary to notify a specific user, the contents of notification to the specific user and the e-mail address of the specific user are transferred from the application server 16 to the mail transmission / reception server 18 to transmit / receive the mail. The server 18 creates an e-mail describing the transferred notification contents, sets the e-mail address transferred from the application server 16 as a destination of the created e-mail, and then sends the e-mail via the mail server 20. To send. As a result, the above e-mail is sent from the mail server 20 via the plurality of mail servers 24 connected to the Internet 22 to the domain specified in the e-mail address set as the destination (out of the e-mail addresses). It reaches the mail server 24 of the domain indicated by the character string on the right side of “@” and is stored in the mailbox of the specific user. Then, when a specific user performs an operation of receiving an e-mail addressed to himself / herself through the client terminal 26, the e-mail is transferred from the specific user's mailbox to the client terminal 26, and the specific use is performed. A specific user is notified when an e-mail is received by the user.

  However, if there is an error in the e-mail address entered by the user when registering the user information described above, the e-mail sent to the user will be sent to the user even if the e-mail is sent as described above. Since it does not reach, there arises a disadvantage that the user cannot be notified. For this reason, if the user information is transferred from the web server 14 at the time of registration of the user information, the application server 16 is improper that the email address included in the transferred user information does not reach the email. In order to determine whether it is an address, the e-mail address is transferred to the mail transmission / reception server 18, and a test mail is sent to the mail transmission / reception server 18 (e-mail for determining whether the e-mail address is an inappropriate address). Is instructed to send. When the e-mail address is transferred from the application server 16 and an instruction to send a test mail is given, the mail transmission / reception server 18 executes the test mail sending process shown in FIG. 2 by the CPU 18A executing the test mail sending program. .

  In this test mail transmission process, first, in step 50, a body of a predetermined content is described in a text format with a single part structure, and a test mail without an attached file is created. In step 52, the e-mail address notified from the application server 16 is set as the transmission destination for the test mail created in step 50. Note that an e-mail address corresponding to a specific mail box provided in the mail server 20 is set as the test e-mail transmission source e-mail address.

  The mail transmission / reception server 18 assigns serial numbers to the individual test mails transmitted by the test mail transmission process in the order in which the test mails are transmitted. In the next step 54, the application server processes the test mails created in step 50. A value obtained by calculating the hash value by inputting the information including the date and time when the transmission is instructed from 16 and the serial number assigned to the test mail created in Step 50 into the hash function, and converting the calculated hash value into a decimal number Appends as a mail specific hash to the end of the body of the test mail. Note that the information used for generating the mail specific hash is not limited to the above date and time and serial number, and in the present embodiment, the mail specific hash is used as identification information for identifying individual test mails. If the information is different for each test mail, the mail specific hash generated using the information is also different for each test mail, and can be used to generate the mail specific hash.

  In step 56, the mail server 20 is instructed to send a test mail. As a result, a test mail having a single part structure, a body text described in a text format, and a mail specific hash added thereto is sent via the Internet 22 using the e-mail address notified from the application server 16 by the mail server 20 as a transmission destination. Sent by In step 58, the mail specific hash, the transmission date and time, and the transmission destination mail address are extracted from the transmitted test mail information, registered in the transmission mail information DB in association with each other, and the test mail transmission process is terminated.

  The test mail transmitted by the above-mentioned test mail transmission process passes through a plurality of mail servers 24 connected to the Internet 22 from the mail server 20, and is normally specified in an e-mail address set as a transmission destination. It is stored in the mailbox (the mailbox corresponding to the character string on the left side of “@” in the email address) of the user who has entered the user information and has reached the mail server 24 of the domain. Then, when the user performs an operation of receiving an electronic mail, the test mail is transferred from the user's mailbox to the client terminal 26, and the test mail is received by the user. In the present embodiment, a user who performs a user information input operation and receives a test mail from the website management system 12 does not need to perform a reply operation on the received test mail, and also performs a reply operation on the body of the test mail. Since it is clearly stated that the e-mail is not required, an e-mail replying to the test e-mail is not normally sent from the user.

  On the other hand, when there is an error in the email address entered by the user when registering user information (for example, when there is no mailbox corresponding to the character string on the left side of "@" in the email address) The mail server 24 that received the test mail (the mail server 24 corresponding to the e-mail address set as the transmission destination in the test mail) cannot store the received test mail in the mailbox specified by the e-mail address. (The test mail is undelivered), and the mail server 24 creates an error mail in a predetermined format with the sender address set in the test mail as the destination, and the created error mail Sent. In addition, when the mail server 24 corresponding to the e-mail address set as the transmission destination in the test mail is temporarily out of order, another mail server trying to transfer the test mail to the mail server 24 24 cannot transfer the test mail (the test mail is undeliverable), the same error mail is created and transmitted by the other mail server 24. The transmitted error mail reaches the mail server 20 of the website management system 12 via a plurality of mail servers 24 and is stored in a specific mailbox provided in the mail server 20.

  However, since the error mail that arrives at the mail server 20 and is stored in a specific mailbox is an error mail that is transmitted by the unspecified mail server 24, its contents and formats are various and comply with the RFC rules. There are a lot of error mails that don't. In addition, as described above, although the reply operation to the test mail is unnecessary, depending on the user who received the test mail, the reply operation to create / send an email replying to the received test mail is erroneously performed. There is a possibility that an e-mail sent by a user performing a reply operation may also be stored in a specific mailbox. Furthermore, since the e-mail address of a specific mailbox is made public, there is a possibility that an irrelevant e-mail (so-called spam mail or the like) may be transmitted to the specific mailbox.

  For this reason, in the mail transmission / reception server 18, the mail non-delivery determination program is repeatedly executed at regular intervals by the CPU 18A, so that the mail non-delivery determination process described below is repeatedly performed at regular intervals. In this mail non-delivery determination process, first, in step 60, a specific mailbox on the mail server 20 is accessed, and an e-mail (new mail) newly stored in the specific mailbox is acquired (downloaded to the receiving folder). Try. In the next step 62, it is determined whether or not new mail has been acquired from the specific mailbox in step 60. If the determination is negative, the mail non-delivery determination process is temporarily terminated.

  On the other hand, if new mail can be acquired from a specific mailbox, the determination in step 62 is affirmed and the process proceeds to step 64, and a single new mail is extracted from the acquired new mail as a determination target electronic mail. . In the next step 66, it is determined whether or not the determination target electronic mail has a multipart structure. As an example, as shown in Fig. 4, the character string "Content-Type: multipart / *" (where "*" is an arbitrary character string) exists in the multipart structure e-mail. Can be performed by searching the character string for the e-mail to be determined and determining whether or not the character string has been extracted as a result of the search. This multi-part structure is one of the features of error mail that complies with the RFC rules. Even if the error mail is an error mail that does not comply with the RFC rules, at least the condition of “multi-part structure” is satisfied. It has been confirmed by the present inventors. For this reason, if the determination in step 66 is negative (when the determination target e-mail has a single-part structure), it can be determined that the determination target e-mail is not an error mail, so the process returns to step 62 and another new mail is returned. If there is no mail, the process is terminated, and if there is another new mail, this is taken out as an e-mail to be determined.

  The test mail created and transmitted by the mail transmission / reception server 18 has a single part structure, and an electronic mail transmitted from the client terminal 26 by a user performing a reply operation to an electronic mail having a single part structure is usually Since the single-part structure is maintained, it is possible to exclude the electronic mail transmitted by the user performing a reply operation on the received test mail from the determination target by the determination in step 66. Step 66 corresponds to the first determination means according to the present invention.

  On the other hand, if the determination in step 66 is affirmative (when the determination target electronic mail has a multi-part structure), the process proceeds to step 68, and the first character string “message / delivery-status” is determined for the determination target electronic mail. In the next step 70, it is determined whether or not the first character string has been extracted by the search in step 68. Steps 68 and 70 correspond to the second determination means according to the present invention. If the email to be determined is an error email that conforms to the RFC rules, as shown in FIG. 4 as an example, the first character string is present in the email to be determined. If the determination in step 70 is affirmative, it can be determined that the e-mail to be determined is an error mail transmitted from the mail server 24 because the test mail has not been delivered.

  For this reason, when the determination in step 70 is affirmed, the process proceeds to step 72, and the e-mail address set as the transmission destination in the test mail corresponding to the e-mail to be determined is recognized. This e-mail address is recognized by first searching for a mail specific hash that exists in the determination target e-mail, extracting the mail specific hash found by this search from the determination target e-mail, and extracting the e-mail address. By searching the transmission mail information DB using the specific hash as a key, and extracting the transmission destination mail address registered in the transmission mail information DB in association with the mail specific hash extracted by the search from the transmission mail information DB It can be carried out. When the process of step 72 is performed, the process proceeds to step 102 where the e-mail address recognized in step 72 is notified to the application server 16 as an invalid e-mail address from which the transmitted e-mail is not delivered. Return to. Step 102 corresponds to the output means according to the present invention.

  Thereby, the application server 16 can recognize that the e-mail address input by the user at the time of registration of the user information is inappropriate, and reconfirm the input e-mail address to the user. Can be processed to modify the e-mail address as necessary. Note that the timing of requesting reconfirmation of the e-mail address depends on the timing of receiving the error mail. If the corresponding error mail is received immediately after sending the test mail, enter the user information. The above process can be performed on the user immediately after the test, but if there is a time difference of several hours to one day after sending the test mail and receiving the corresponding error mail, the user Next, the above processing is performed when a specific website is accessed.

  By the way, if the determination in the previous step 70 is negative, the first character string “message / delivery-status” is not included by the inventors of the present application, although it does not correspond to the error mail condition in the RFC rules. Since it has been confirmed that there is also a mail server that transmits an error mail, the e-mail to be determined may be an error mail even in the above case. For this reason, in the mail non-delivery determination processing according to the present embodiment, when the determination in step 70 is negative, the following processing is further performed on the determination target electronic mail.

  That is, if the determination in step 70 is negative, first, in step 74, the second character string “text / html” is searched for the e-mail to be determined, and in the next step 76, the search in step 74 is performed. It is determined whether or not the second character string is extracted from the determination target electronic mail. This second character string is a character string added to the e-mail when the body of the e-mail is described in the HTML format. If the determination in step 76 is affirmative, the e-mail to be determined has a body. It is described in the HTML format. As described above, the test mail transmitted from the mail transmission / reception server 18 has the text described in the text format, and the inventors of the present application have not reached the e-mail in which the text is described in the text format. It has been confirmed that the body of the error mail sent from the mail server has the characteristic that it is not changed from the text format. Therefore, if the determination in step 76 is affirmative, it is determined that the e-mail to be determined is not an error e-mail, but an e-mail created and transmitted by the user, or an irrelevant e-mail such as spam mail. it can. For this reason, if the determination in step 76 is affirmative, the process returns to step 62, and if there is no other new mail, the process is terminated, and if there is another new mail, it is taken out as the determination target electronic mail.

  If the determination in step 76 is negative, the process proceeds to step 78 to determine whether or not a file is attached to the determination target electronic mail. As described above, the test mail transmitted from the mail transmission / reception server 18 has no attached file, and the inventors of the present application rarely add an additional file to the error mail transmitted from the mail server. Make sure that there is. Therefore, if the determination in step 78 is affirmed, it is determined that the e-mail to be determined is not an error e-mail, but an e-mail created and transmitted by the user, or an irrelevant e-mail such as spam mail. it can. For this reason, even if the determination in step 78 is affirmative, the process returns to step 62, and if there is no other new mail, the process is terminated, and if there is another new mail, this is taken out as the determination target electronic mail. Steps 74 to 78 described above correspond to the third determination means according to the present invention. In particular, steps 74 and 76 are the third determination means according to claim 3, and step 78 is the claim 4 according to claim 4. This corresponds to the third determination means.

  If the determination in step 78 is negative, the process proceeds to step 80 to search whether or not a mail specific hash is present in the determination target electronic mail. In the next step 82, the search in step 80 is performed. To determine whether or not a mail specific hash exists in the e-mail to be determined. If the determination in step 82 is affirmed, the process proceeds to step 84, where the mail specific hash found by the search in step 80 is extracted from the e-mail to be determined, and then the transmitted mail information DB is extracted using the extracted mail specific hash as a key. Search for. In the next step 86, it is determined whether or not the mail specific hash has been extracted from the transmission mail information DB by the search in step 84 (whether the mail specific hash extracted from the determination target electronic mail has been registered in the transmission mail information DB). .

  If the determination in step 86 is also affirmed, the process proceeds to step 88, and information that is estimated to correspond to the transmission date and time of the original test mail for the determination target e-mail (for example, the original of the determination target e-mail information) In the next step 90, the transmission date and time of the original test mail found by the search in step 88 is searched. After extracting information estimated to correspond to the e-mail to be determined, the transmission mail information DB is searched using the extracted information as a key. In step 92, it is determined whether or not the information searched in step 90 has been registered as the transmission date / time in the transmission mail information DB. If this determination is affirmed, the information (transmission date and time) extracted from the transmitted mail information DB in the search in step 90 is transmitted in association with the mail specific hash used as a key in the previous search in step 84. You may make it further determine whether it is registered into mail information DB.

  If the determination in step 92 is also affirmed, the process proceeds to step 94, where information estimated to correspond to the destination test mail address of the original test mail (for example, information on the determination target e-mail) is transferred to step 94. The character string following the character string “To:” existing in the portion estimated to correspond to the original test mail is searched, and in the next step 96, the original test mail found by the search in step 94 is searched. After extracting information estimated to correspond to the transmission destination mail address from the e-mail to be determined, the transmission mail information DB is searched using the extracted information as a key. In step 98, it is determined whether or not the information searched in step 96 is registered as a transmission destination mail address in the transmission mail information DB. If this determination is affirmed, the information (destination mail address) extracted from the transmitted mail information DB in the search in step 94 is the mail specific hash and the previous key used as the key in the previous step 84 search. It may be further determined whether or not it is registered in the transmission mail information DB in association with the transmission date and time used as a key in the search in step 90.

  If the determination in step 98 is also affirmed, the mail specific hash registered in the transmission mail information DB, the transmission date and time, and the transmission destination mail address are present in the determination target electronic mail (FIG. 4 also). Reference), it can be determined that the e-mail to be determined includes the information of the corresponding test mail. In addition, the inventors of the present application have confirmed that an error mail transmitted from a mail server when a certain e-mail is undelivered has a feature that information of the original e-mail is included. Yes. Therefore, if the determination in step 92 is also affirmed, it can be determined that the e-mail to be determined is an error e-mail, so the process proceeds to step 102 and the e-mail address extracted in the previous step 88 is sent to the application server 16. As an invalid e-mail address at which the transmitted e-mail is not delivered, and the process returns to step 62. Also in this case, the application server 16 can perform processing such as requesting the user to reconfirm the input e-mail address.

  By performing the above processing, it is possible to determine with high accuracy whether the received e-mail is an error e-mail, that is, whether the corresponding test e-mail has not arrived at the destination, and the e-mail address entered by the user However, it is possible to determine with high accuracy whether or not the transmitted e-mail is an invalid e-mail address that is not delivered. In addition, each determination in the above processing is received because it does not require complicated work or processing such as collecting character strings to be registered in the table or periodically updating character strings registered in the table. It is possible to easily determine whether the electronic mail is an error mail, that is, whether the corresponding test mail has not arrived at the transmission destination.

  In the above mail arrival determination process, if any of the determinations in steps 82, 86, 92, and 98 is denied, the determination target e-mail does not include any transmitted test mail information. Although it is very unlikely that the e-mail to be judged is an error e-mail because it can be judged, in this case, the e-mail to be judged has a multipart structure, the body is written in text format, and the attached file is also Since it has the feature that there is no error, there is a possibility that the determination may be omitted if it is determined that the e-mail to be determined is not an error mail. For this reason, in the mail non-delivery determination process according to the present embodiment, priority is given to eliminating omission of determination, and if any of the determinations in steps 82, 86, 92, and 98 is denied, the process proceeds to step 100. After determining that the e-mail to be determined cannot be analyzed and storing it in a predetermined folder, the process returns to step 62. In this case, the analysis (determination of whether or not the error mail is an error mail) of the e-mail stored in the predetermined folder is left to the operator, but the ratio of the e-mail stored in the predetermined folder in step 100 is extremely high. The analysis of electronic mail stored in a predetermined folder is not burdened by the operator.

  In the above description, a mode in which a test mail is transmitted and the mail non-delivery determination process is performed in order to confirm whether there is an error in the e-mail address input by the user when registering the user information has been described. The present invention is not limited to this. Considering that the transmitted e-mail may be undeliverable due to a temporary malfunction of the mail server, for example, e-mail having important contents is transmitted. After that, it is possible to apply to a mode in which the above-mentioned mail non-delivery determination process is performed to monitor the non-delivery of the transmitted electronic mail (whether it is returned as an error mail).

  In the above description, the mail transmission / reception server 18 of the website management system 12 is functioned as the mail non-delivery determination device according to the present invention. ) Is not limited to the above, and it is also possible to cause another computer such as a PC to function as a mail nondelivery determination device.

  In the above description, the mail non-delivery determination program according to the present invention is stored (installed) in the mail transmission / reception server 18 in advance. However, the mail non-delivery determination program according to the present invention is a CD-ROM or DVD- It is also possible to provide the information recorded in a recording medium such as a ROM.

10 Computer System 18 Mail Transmission / Reception Server 20 Mail Server 22 Internet 24 Mail Server 26 Client Terminal

Claims (7)

Arbitrary e-mails with a single-part structure with the body text written in text format, with the e-mail specific hash added by calculating the hash value by entering different information for each e-mail into the hash function. Email sending means for sending the email address of
When an e-mail having a transmission destination e-mail address set in the predetermined e-mail transmitted by the e-mail transmission unit is received, it is determined whether or not the received e-mail has a multi-part structure. First determination means;
When the received electronic mail is determined to have a multi-part structure by the first determination means, a first determination is made as to whether or not a character string “message / delivery-status” is included in the received electronic mail. 2 determination means;
When the second determination means determines that the received e-mail does not contain the character string “message / delivery-status”, the body included in the received e-mail information is converted from the text format. A third determination means for determining whether or not it has been changed;
When the third determination means determines that the body has not been changed from the text format, it is added to the predetermined e-mail corresponding to the received e-mail to the received e-mail information Fourth determination means for determining whether or not the information of the predetermined email including the mail specific hash is included;
The received electronic mail is determined to have a multi-part structure by the first determining means, and the character string “message / delivery-status” is not included in the received electronic mail by the second determining means. And the third determination means determines that the body has not been changed from the text format, and the fourth determination means adds the received e-mail to the received e-mail information. A predetermined e-mail corresponding to the received e-mail is determined to include information on the predetermined e-mail including the mail specific hash added to the predetermined e-mail corresponding to An output means for outputting a determination result that the destination has not been reached;
E-mail nondelivery determination device.   The output means also has a predetermined response corresponding to the received electronic mail even when the second determination means determines that the received electronic mail includes the character string “message / delivery-status”. 2. The mail non-delivery determination device according to claim 1, wherein a determination result that the electronic mail has not arrived at the transmission destination is output.   The third determination means searches whether or not the character string “text / html” is included in the received e-mail information, and the character string “text / html” is not extracted by the search. In this case, the mail non-delivery determination device according to claim 1, wherein the body included in the received electronic mail information is determined not to be changed from a text format. The third determining means also determines whether a file is attached to the received e-mail,
The fourth determination unit determines that the third determination unit determines that the body has not been changed from the text format and determines that no file is attached to the received email. 2. The mail non-delivery determination device according to claim 1, wherein it is determined whether or not predetermined electronic mail information is included. The mail transmission means stores a part or all of the information of the transmitted predetermined electronic mail in a storage means,
The fourth determination means checks the received information by comparing the information of the part where the original e-mail information is set in the received e-mail information with the information stored in the storage means. And determining whether or not the predetermined e-mail corresponding to the received e-mail is included, and whether or not the predetermined e-mail information corresponding to the received e-mail information is included. The mail nondelivery determination device according to claim 1. The mail transmitting means adds the mail specific hash to the body of the predetermined e-mail and transmits the mail, and as part of the information of the predetermined e-mail, the mail specific hash , the transmission date and time, and the destination electronic The mail address is associated and stored in the storage means,
The fourth determination means includes, in the portion where the original e-mail information is set in the received e-mail information, the e- mail specific hash , transmission date and time stored in association with the storage means, By determining whether or not all the destination e-mail addresses are included, it is possible to determine the predetermined e-mail corresponding to the received e-mail, and to correspond to the received e-mail information 6. The mail nondelivery determination device according to claim 5, wherein it is determined whether or not the predetermined electronic mail information is included. Computer
Arbitrary e-mails with a single-part structure with the body text written in text format, with the e-mail specific hash added by calculating the hash value by entering different information for each e-mail into the hash function. Mail sending means for sending the email address of
When an e-mail having a transmission destination e-mail address set in the predetermined e-mail transmitted by the e-mail transmission unit is received, it is determined whether or not the received e-mail has a multi-part structure. First determination means;
When the received electronic mail is determined to have a multi-part structure by the first determination means, a first determination is made as to whether or not a character string “message / delivery-status” is included in the received electronic mail. 2 determination means,
When the second determination means determines that the received e-mail does not contain the character string “message / delivery-status”, the body included in the received e-mail information is converted from the text format. Third determination means for determining whether or not the change has been made;
When the third determination means determines that the body has not been changed from the text format, it is added to the predetermined e-mail corresponding to the received e-mail to the received e-mail information 4th determination means which determines whether the information of the said predetermined | prescribed email containing the said mail specific hash is contained,
The received electronic mail is determined to have a multi-part structure by the first determining means, and the received electronic mail includes a character string “message / delivery-status” by the second determining means. It is determined that the text has not been changed from the text format by the third determining means, and the received information is received in the received e-mail information by the fourth determining means. When it is determined that the information of the predetermined e-mail including the mail specific hash added to the predetermined e-mail corresponding to the e-mail is included, the predetermined e-mail corresponding to the received e-mail A mail non-delivery judgment program that functions as an output means that outputs the judgment result that mail has not arrived at the destination.

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