JP5846590B2 - E-mail monitoring apparatus, outgoing mail server, e-mail monitoring method and program - Google Patents

Description

  The present invention relates to an electronic mail monitoring apparatus, a transmission mail server, an electronic mail monitoring method, and a program for monitoring transmitted electronic mail.

  In recent years, the act of maliciously using another person's e-mail address, impersonating an e-mail sender (sender), and sending a so-called junk e-mail has become a problem. Junk mail is often sent in large quantities, which may cause tight communication lines.

  In order to reduce the transmission of such spam mails, a technique for limiting the number of mails that can be transmitted per day from the same electronic mail address has been considered (for example, see Patent Document 1). Thereby, transmission of the spam mail transmitted in large quantities can be suppressed.

JP 2006-128917 A

  However, the technique described in Patent Document 1 has a problem in that even if a large amount of electronic mail is transmitted from a legitimate user, the transmission is suppressed.

  An object of the present invention is to provide an electronic mail monitoring apparatus, a transmission mail server, an electronic mail monitoring method, and a program that solve the above-described problems.

A first electronic mail monitoring apparatus according to an aspect of the present invention includes:
An acquisition unit that acquires an e-mail transmitted from a communication terminal and acquires member identification information of the user who transmitted the e-mail from an e-mail server connected to the e-mail monitoring device ;
An extraction unit configured to extract the email or al the acquisition unit has acquired, the communication terminal identification information assigned to the communication terminal that has transmitted the e-mail,
For each member identification information acquired by the acquisition unit in unit time, a calculation unit that calculates a unique number of the communication terminal identification information;
A verification unit that determines whether the unique number of the communication terminal identification information for each member identification information calculated by the calculation unit exceeds a predetermined first threshold;
The verification unit includes a notification unit that performs a predetermined first notification including the member identification information determined that the unique number of the communication terminal identification information has exceeded the first threshold to a preset notification destination. .

A second electronic mail monitoring apparatus according to an aspect of the present invention is provided.
An acquisition unit that acquires an e-mail transmitted from a communication terminal and acquires member identification information of the user who transmitted the e-mail from an e-mail server connected to the e-mail monitoring device ;
Email or al acquired by the acquiring unit, an extraction unit to extract a communication terminal identification information assigned to the communication terminal that has transmitted the e-mail,
For each member identification information acquired by the acquisition unit in unit time, a calculation unit that calculates a unique number of countries or regions corresponding to the communication terminal identification information;
A verification unit that determines whether the unique number of the country or region for each member identification information calculated by the calculation unit exceeds a predetermined second threshold;
The verification unit includes a notification unit that performs a predetermined second notification including the member identification information determined that the unique number of the country or the region has exceeded the second threshold value to a preset notification destination.

The first outgoing mail server according to one aspect of the present invention is:
An authentication unit for authenticating the user;
A storage unit for storing authentication information for performing the authentication;
When the authentication unit succeeds in authenticating the user using authentication information stored in the storage unit, an acquisition unit that acquires an email transmitted from a communication terminal;
User identification information indicating the user who transmitted the e-mail is extracted from the authentication information, and is given to the e-mail acquired by the acquisition unit or the communication terminal that transmitted the e-mail from the connection process with the communication terminal. An extractor for extracting communication terminal identification information;
For each user identification information extracted by the extraction unit in unit time, a calculation unit that calculates a unique number of the communication terminal identification information;
A verification unit that determines whether the unique number of the communication terminal identification information for each of the user identification information calculated by the calculation unit exceeds a predetermined first threshold;
A notifying unit configured to perform a predetermined first notification including the user identification information, which is determined that the unique number of the communication terminal identification information exceeds the first threshold, to a preset notification destination; Yes, and
The extraction unit extracts an email address or member identification information as the user identification information .

The second outgoing mail server according to one aspect of the present invention is:
An authentication unit for authenticating the user;
A storage unit for storing authentication information for performing the authentication;
When the authentication unit succeeds in authenticating the user using authentication information stored in the storage unit, an acquisition unit that acquires an email transmitted from a communication terminal;
User identification information indicating the user who transmitted the e-mail is extracted from the authentication information, and is given to the e-mail acquired by the acquisition unit or the communication terminal that transmitted the e-mail from the connection process with the communication terminal. An extractor for extracting communication terminal identification information;
For each user identification information extracted by the extraction unit in unit time, a calculation unit that calculates a unique number of countries or regions corresponding to the communication terminal identification information;
A verification unit that determines whether a unique number of the country or region for each of the user identification information calculated by the calculation unit exceeds a predetermined second threshold;
And a notifying unit configured to perform a predetermined second notification including the user identification information determined that the unique number of the country or region has exceeded the second threshold value to a preset notification destination. And
The extraction unit extracts an email address or member identification information as the user identification information .

A first e-mail monitoring method according to an aspect of the present invention includes:
An email monitoring method for monitoring email sent from a communication terminal,
Processing for obtaining an email sent from the communication terminal;
A process of acquiring member identification information of the user who transmitted the e-mail from an e-mail server connected to the e-mail monitoring device;
A process of extracting the acquired e-mail or, et al., The communication terminal identification information assigned to the communication terminal that has transmitted the e-mail,
For each of the acquired member identification information in a unit time, a process of calculating a unique number of the communication terminal identification information or a unique number of a country or region corresponding to the communication terminal identification information ;
A process of determining whether the calculated unique number of the communication terminal identification information for each member identification information or the unique number of the country or region exceeds a predetermined threshold ;
A process of performing a predetermined notification including the member identification information determined that the unique number of the communication terminal identification information or the unique number of the country or region exceeds the threshold value to a preset notification destination is performed.

A second e-mail monitoring method according to an aspect of the present invention includes:
An e-mail monitoring method for a sending mail server for sending an e-mail sent from a communication terminal,
A process of authenticating the user;
When the user is successfully authenticated using the authentication information stored in the storage unit, a process of obtaining an e-mail transmitted from the communication terminal;
A process of extracting user identification information indicating the user who transmitted the e-mail from the authentication information ;
A process of extracting the acquired e-mail or the communication terminal and the connection process communication terminal identification information assigned to the communication terminal transmitting the electronic mail from,
For each user identification information extracted by the extracting unit in a unit time, a process of calculating a unique number of countries or regions corresponding to the unique number or the communication terminal identification information of the communication terminal identification information,
Unique number of unique numbers or the country or region of the communication terminal identification information for each said user identification information issued calculated and the process of determining whether more than a predetermined threshold value,
A process of performing a predetermined notification including the user identification information determined that the unique number of the communication terminal identification information or the unique number of the country or region exceeds the threshold , to a preset notification destination ;
Have
In the process of extracting the user identification information, an e-mail address or member identification information is extracted as the user identification information
It is characterized by that .

The first program according to one aspect of the present invention is:
On the computer,
A procedure for obtaining an email sent from a communication terminal;
A process of acquiring member identification information of the user who transmitted the e-mail from an e-mail server connected to the e-mail monitoring device;
A step of extracting the acquired e-mail or, et al., The communication terminal identification information assigned to the communication terminal that has transmitted the e-mail,
A procedure for calculating a unique number of the communication terminal identification information or a unique number of countries or regions corresponding to the communication terminal identification information for each of the acquired member identification information in a unit time;
Determining whether the calculated unique number of the communication terminal identification information for each member identification information or the unique number of the country or region exceeds a predetermined threshold ;
And a procedure of performing a predetermined notification including the member identification information determined that the unique number of the communication terminal identification information or the unique number of the country or region exceeds the threshold to a preset notification destination.

The second program according to one aspect of the present invention is:
A program for causing a computer to send an e-mail sent from a communication terminal ,
A procedure for authenticating the user;
If the user is successfully authenticated using the authentication information stored in the storage unit, a procedure for obtaining an e-mail transmitted from the communication terminal;
A procedure for extracting user identification information indicating a user who has transmitted the e-mail from the authentication information ;
A step of extracting the acquired e-mail or the communication terminal and the connection process communication terminal identification information assigned to the communication terminal transmitting the electronic mail from,
For each user identification information extracted by the extracting unit in a unit time, a step of calculating a unique number of countries or regions corresponding to the unique number or the communication terminal identification information of the communication terminal identification information,
Unique number of unique numbers or the country or region of the communication terminal identification information for each said user identification information issued calculated and the procedure for determining whether more than a predetermined threshold value,
A procedure of performing a predetermined notification including the user identification information determined that the unique number of the communication terminal identification information or the unique number of the country or region has exceeded the threshold , to a preset notification destination ;
Have
In the procedure for extracting the user identification information, an email address or member identification information is extracted as the user identification information.
It is characterized by that .

  As described above, in the present invention, it is possible to more accurately detect the transmission of junk mail.

It is a figure which shows one Embodiment of the communication system which has an electronic mail monitoring apparatus of this invention. It is a figure which shows an example of an internal structure of the electronic mail monitoring apparatus shown in FIG. It is a figure which shows an example of the matching memorize | stored in the memory | storage part shown in FIG. It is a figure which shows the other example of the correlation memorize | stored in the memory | storage part shown in FIG. It is a flowchart for demonstrating an example of the email monitoring method in the email monitoring apparatus shown in FIG. It is a figure which shows an example of the country information memorize | stored in the memory | storage part shown in FIG. It is a flowchart for demonstrating an example of the email monitoring method using the country information in the email monitoring apparatus shown in FIG. It is a figure which shows one Embodiment of the communication system which has a transmission mail server of this invention. It is a figure which shows an example of an internal structure of the transmission mail server shown in FIG. It is a figure which shows an example of the authentication information memorize | stored in the memory | storage part shown in FIG. It is a flowchart for demonstrating an example of the email monitoring method in the transmission mail server shown in FIG. It is a flowchart for demonstrating an example of the electronic mail monitoring method using the country information in the transmission mail server shown in FIG.

Embodiments of the present invention will be described below with reference to the drawings.
(First embodiment)
FIG. 1 is a diagram showing an embodiment of a communication system having an electronic mail monitoring apparatus according to the present invention.

  In this embodiment, as shown in FIG. 1, the electronic mail monitoring apparatus 100 of the present invention, the outgoing mail server 200, the incoming mail server 300, the administrator terminal 400, and the communication terminals 500-1 to 500-n (n is , Integer).

  The e-mail monitoring apparatus 100 monitors e-mails transmitted from the communication terminals 500-1 to 500-n.

  FIG. 2 is a diagram showing an example of an internal configuration of the electronic mail monitoring apparatus 100 shown in FIG.

  As shown in FIG. 2, the email monitoring apparatus 100 shown in FIG. 1 includes an acquisition unit 101, an extraction unit 102, a calculation unit 103, a verification unit 104, a notification unit 105, a transmission control unit 106, A storage unit 107 is provided.

  The acquisition unit 101 acquires an email transmitted from the communication terminals 500-1 to 500-n to the received mail server 300 via the transmitted mail server 200.

  The extraction unit 102 is given from the email acquired by the acquisition unit 101 to user identification information such as an email address of a transmission source indicating the user who sent the email and the communication terminal that sent the email. And communication terminal identification information such as an IP (Internet Protocol) address. Such information is generally included in the header of the electronic mail acquired by the acquisition unit 101. Further, the extraction unit 102 writes the extracted user identification information and communication terminal identification information in the storage unit 107 in association with the date / time information.

  The calculation unit 103 calculates a unique number of IP addresses (the number of different IP addresses) for each email address extracted by the extraction unit 102. Here, the calculation unit 103 calculates the unique number of IP addresses of the emails acquired by the acquisition unit 101 in a preset unit time (for example, 1 minute or 1 hour). In addition, the calculation unit 103 outputs the calculated unique number of IP addresses to the verification unit 104.

  The verification unit 104 compares the unique number of IP addresses output from the calculation unit 103 with a preset threshold value (first threshold value), and the unique number of IP addresses exceeds the first threshold value. Determine whether or not. The first threshold value is stored in the storage unit 107. In addition, the verification unit 104 notifies the notification unit 105 and the transmission control unit 106 of the determination result.

  When the notification from the verification unit 104 indicates that the unique number of IP addresses has exceeded the first threshold, the notification unit 105 sets a predetermined notification (first notification) as a preset notification destination. To the administrator terminal 400. This notification may include a mail address of an electronic mail whose unique number of IP addresses exceeds the first threshold, and may further include the IP address and date / time information.

  If the notification from the verification unit 104 indicates that the IP address unique number exceeds the first threshold, the transmission control unit 106 sends an e-mail with the IP address unique number exceeding the first threshold. Stop sending e-mails from In addition, when the notification from the verification unit 104 indicates that the unique number of IP addresses does not exceed the first threshold, the transmission control unit 106 uses the email address of the email as the sender. The electronic mail is transmitted to the incoming mail server 300.

  The storage unit 107 stores the user identification information and the communication terminal identification information written by the extraction unit 102 in association with the date / time information.

  FIG. 3 is a diagram illustrating an example of association stored in the storage unit 107 illustrated in FIG. 2.

  As shown in FIG. 3, the storage unit 107 illustrated in FIG. 2 includes an email address that is user identification information of an email transmission source, an IP address that is communication terminal identification information of an email transmission source, and a date and time. Information is stored in association with each other. Further, the number of addresses of the e-mail may be associated with these pieces of information. As shown in FIG. 3, there are electronic mails having different IP addresses even though they are transmitted from the same mail address. The date and time information includes the date and time when the outgoing mail server 200 received the email, the date and time when the outgoing mail server 200 sent the email, the date and time when the acquisition unit 101 acquired the email, and the storage unit 107 stored the association. It shows the date and time etc.

  Further, the acquisition unit 101 may acquire a member ID corresponding to the mail address from the transmission mail server 200, and the storage unit 107 may store the member ID, the IP address, and the date / time information in association with each other. .

  FIG. 4 is a diagram illustrating another example of association stored in the storage unit 107 illustrated in FIG.

  As shown in FIG. 4, the storage unit 107 shown in FIG. 2 includes a member ID that is user identification information that is an e-mail transmission source, an IP address that is communication terminal identification information that is an e-mail transmission source, Information is stored in association with each other. Further, the number of addresses of the e-mail may be associated with these pieces of information.

  The member ID is not acquired by the acquisition unit 101 from the transmission mail server 200, but a member ID corresponding to the email address is registered in advance, and the member ID is associated with the email address and stored in the storage unit 107. May be stored.

  The outgoing mail server 200 authenticates a user who uses the connected communication terminals 500-1 to 500-n. At this time, the outgoing mail server 200 authenticates the user by using authentication information of the user's preset email address or member ID (member identification information) and password. Moreover, the transmission mail server 200 transmits the electronic mail transmitted from the communication terminals 500-1 to 500-n to the electronic mail monitoring apparatus 100 when the authentication is successful. Although FIG. 1 shows an example in which there is one outgoing mail server 200, a plurality of outgoing mail servers 200 may be provided.

  The received mail server 300 sends the email transmitted from the communication terminals 500-1 to 500-n via the sent mail server 200 and the email monitoring device 100 to the destination indicated by the destination information included in the header of the email. Send.

  The administrator terminal 400 is a communication device operated by an administrator who manages the electronic mail monitoring apparatus 100. The administrator terminal 400 includes an output unit such as a display and a speaker, and can output a notification from the notification unit 105 from the output unit. Thereby, the administrator can recognize the notification from the notification unit 105.

  The communication terminals 500-1 to 500-n are communication devices that can be operated by a user and transmit an electronic mail. The communication terminals 500-1 to 500-n may be operated by a legitimate user, or may be operated by a malicious user who intends to transmit the spam mail as described above.

  Hereinafter, an e-mail monitoring method in the e-mail monitoring apparatus 100 shown in FIG. 1 will be described.

  FIG. 5 is a flowchart for explaining an example of the e-mail monitoring method in e-mail monitoring apparatus 100 shown in FIG.

  First, when the e-mail monitoring apparatus 100 receives e-mails transmitted from the communication terminals 500-1 to 500-n via the transmission mail server 200, the acquisition unit 101 acquires the received e-mails (step S1). . Subsequently, the extraction unit 102 extracts the transmission source mail address and the transmission source IP address from the electronic mail acquired by the acquisition unit 101 (step S2). The extraction unit 102 writes the extracted mail address and IP address in the storage unit 107 in association with the date / time information.

  The calculation unit 103 refers to the storage unit 107 for each unit time, and calculates the unique number of IP addresses extracted by the extraction unit 102 for that unit time for each mail address (step S3). Subsequently, the verification unit 104 determines whether or not the unique number of IP addresses for each mail address calculated by the calculation unit 103 exceeds a preset first threshold value (step S4).

  For example, the association written in the storage unit 107 by the extraction unit 102 is as shown in FIG. 3, and the unit time is 5 seconds (here, 10:01:25 on July 1, 2012 to 30 seconds). 5 seconds), the calculation unit 103 calculates that the unique number of IP addresses for the mail address “aaa@mail.***.jp” is “4”. In addition, the calculation unit 103 calculates that the unique number of IP addresses for the mail address “bbb@mail.***.jp” is “2”. When the first threshold is “3”, the verification unit 104 determines that the unique number of IP addresses for the mail address “aaa@mail.***.jp” exceeds the first threshold. judge. Further, the verification unit 104 determines that the unique number of IP addresses for the mail address “bbb@mail.***.jp” does not exceed the first threshold.

  If the verification unit 104 determines that the unique number of IP addresses for each email address calculated by the calculation unit 103 has exceeded the first threshold, the notification unit 105 may have sent a junk email (spoofed email). A notification indicating the fact (first notification) is sent to the administrator terminal 400 that is the notification destination (step S5). This notification includes the mail address of the corresponding sender. Further, the IP address and date / time information of the transmission source may be included in this notification.

  When the verification unit 104 determines that the unique number of IP addresses for each mail address calculated by the calculation unit 103 has exceeded the first threshold, the transmission control unit 106 transmits the electronic mail transmitted from the corresponding mail address. The transmission of mail may be stopped (step S6). On the other hand, when the verification unit 104 determines that the unique number of IP addresses for each mail address calculated by the calculation unit 103 does not exceed the first threshold value, the transmission control unit 106 is transmitted from the corresponding mail address. The received e-mail is transmitted (step S7).

  Communication in which the communication terminals 500-1 to 500-n are fixed PCs (personal computers) or the like, or data communication performed by connecting (login) to the server using the member ID and password from the communication terminals 500-1 to 500-n In this case, the IP addresses given to the communication terminals 500-1 to 500-n are semi-fixed. Therefore, even if the email addresses of a plurality of emails are the same, if the IP addresses are different from each other, there is a high possibility that another person has abused the email address. Furthermore, if the transmission frequency of the electronic mail (the number of transmissions within a unit time) is high, it can be determined that there is a high possibility that the electronic mail is a junk mail (spoofed mail). By performing the above-described processing using these properties, it is possible to easily identify spam mail (spoofed mail).

  Further, as described above, not only the determination criterion for spam mail (spoofed mail) is the unique number of IP addresses, but also the country of the transmission source may be added. Generally, the usable range of IP addresses is determined for each country. That is, by referring to a predetermined bit of an IP address, it can be determined in which country the IP address is used. The IP address range and information (country identifier) indicating the country are associated with each other and stored in the storage unit 107 as country information, and the verification unit 104 transmits an e-mail transmitted based on the country information. It may be determined whether there is a possibility of being a junk mail (spoofed mail).

  FIG. 6 is a diagram illustrating an example of the country information stored in the storage unit 107 illustrated in FIG.

  As shown in FIG. 6, the storage unit 107 shown in FIG. 2 stores an IP address range and a country identifier in association with each other. The range of IP addresses corresponding to this country is predetermined all over the world. The country identifier may be any country identifier, and may be a country code set in advance for each country.

  Hereinafter, an e-mail monitoring method using country information in the e-mail monitoring apparatus 100 shown in FIG. 1 will be described.

  FIG. 7 is a flowchart for explaining an example of an e-mail monitoring method using country information in the e-mail monitoring apparatus 100 shown in FIG.

  First, when the e-mail monitoring apparatus 100 receives e-mails transmitted from the communication terminals 500-1 to 500-n via the transmission mail server 200, the acquisition unit 101 acquires the received e-mails (step S11). . Subsequently, the extraction unit 102 extracts the transmission source mail address and the transmission source IP address from the electronic mail acquired by the acquisition unit 101 (step S12). The extraction unit 102 writes the extracted mail address and IP address in the storage unit 107 in association with the date / time information.

  Then, the calculation unit 103 calculates the unique number of IP addresses extracted by the extraction unit 102 per unit time for each mail address (step S13). Subsequently, the verification unit 104 determines whether or not the unique number of IP addresses for each mail address calculated by the calculation unit 103 exceeds a preset first threshold (step S14).

  When the verification unit 104 determines that the unique number of IP addresses for each email address calculated by the calculation unit 103 exceeds the first threshold, the calculation unit 103 corresponds to the email address extracted by the extraction unit 102 in unit time. The country information corresponding to the IP address is extracted based on the IP address to be transmitted and the country information stored in the storage unit 107, and the unique number of the country of the transmission source per unit time is calculated for each mail address (step) S15). Subsequently, the verification unit 104 determines whether or not the country unique number for each email address calculated by the calculation unit 103 exceeds a preset second threshold value (step S16).

  When the verification unit 104 determines that the country unique number for each email address calculated by the calculation unit 103 has exceeded the second threshold, the notification unit 105 may transmit a spam mail (spoofed mail). Notification (second notification) is sent to the administrator terminal 400 that is the notification destination (step S17). This notification includes the mail address of the corresponding sender. Further, the notification may include the IP address of the transmission source, date / time information, and country name.

  For example, the first threshold value is “5”, the second threshold value is “3”, and the IP address of an email sent from the email address “aaa@mail.***.jp” within a unit time is “ 133. ***. ***. 010 (JP) ”, 2 cases,“ 133. ***. ***. 012 (JP) ”, 1 case,“ 134. *** ” *. ***. 0.023 (DE) ", 1 case," 134. ***. ***. 024 (DE) ", 1 case," 135. ***. *** " Consider a case in which there are two cases of “* 009 (US)” and one case of “139. ***. ***. 123 (DE)”. In this case, since the unique number of the IP address is “6” and the unique number of the country is “4”, the notification unit 105 performs notification. Further, for example, the IP address of the e-mail transmitted within the unit time from the mail address “bbb@mail.***.jp” is “133. ***. ***. 014 (JP)”. 2 cases, 1 case with “133. ***. ***. 018 (JP)”, 2 cases with “133. ***. ***. 015 (JP)” , “133. ****. ***. 024 (JP)” is one case, “133. ***. ***. 0.033 (JP)” is two cases, “133. Suppose that there is one item that is “***. ***. 123 (JP)”. In this case, since the unique number of the IP address is “6” and the unique number of the country is “1”, the notification unit 105 does not notify.

  When the verification unit 104 determines that the country unique number for each email address calculated by the calculation unit 103 exceeds the second threshold, the transmission control unit 106 transmits an email sent from the corresponding email address. May be stopped (step S18).

  On the other hand, when the verification unit 104 determines that the unique number of IP addresses for each email address calculated by the calculation unit 103 does not exceed the first threshold, or the country uniqueness for each email address calculated by the calculation unit 103 If it is determined that the number does not exceed the second threshold, the transmission control unit 106 transmits an email transmitted from the corresponding email address (step S19).

  After the processing in step S12, the extraction unit 102 writes the extracted mail address and IP address in association with the date / time information in the storage unit 107, and then does not perform the processing in steps S13 and S14, but in step S15. The calculation unit 103 extracts country information corresponding to the IP address based on the IP address corresponding to the mail address extracted by the extraction unit 102 in unit time and the country information stored in the storage unit 107. Alternatively, the unique number of the transmission source country per unit time may be calculated for each mail address. In this way, even if the verification unit 104 does not exceed the first threshold of the IP address of the transmission source for each mail address, the unique number of the country of the transmission source for each mail address. It can be determined whether or not exceeds the second threshold.

  In this way, by using the country unique number in addition to the IP address unique number as a criterion, it is possible to improve the accuracy of identifying spam mail (spoofed mail). In other words, since it is difficult to send e-mails from a plurality of countries in a short time, the unit time is set short, and the source country is determined based on the range to which the IP address belongs. It can be determined that e-mails sent from more than a few countries are likely to be spam mails (spoofed mails).

  In the above-described example, the case where an e-mail address is used as the user identification information has been described as an example. However, as the user identification information, the member acquired by the acquisition unit 101 from the transmission mail server 200 using the e-mail address as a key. An ID may be used.

In addition, as a judgment criterion for spam mail (spoofed mail), if the sender area (for example, Kanto region or Asia region) can be specified based on the sender's IP address, An area may be used.
(Second Embodiment)
The outgoing mail server 200 may have the function of the electronic mail monitoring apparatus 100 described above.

  FIG. 8 is a diagram showing an embodiment of a communication system having a transmission mail server of the present invention.

  As shown in FIG. 8, the present embodiment is composed of a transmission mail server 210 of the present invention, a reception mail server 300, an administrator terminal 400, and communication terminals 500-1 to 500-n (n is an integer). ing.

  Incoming mail server 300, administrator terminal 400 and communication terminals 500-1 to 500-n are the same as those shown in FIG.

  The outgoing mail server 210 is a communication device that has both the function of the outgoing mail server 200 shown in FIG. 1 and the function of the electronic mail monitoring apparatus 100.

  FIG. 9 is a diagram showing an example of the internal configuration of the outgoing mail server 210 shown in FIG.

  As shown in FIG. 9, the transmission mail server 210 shown in FIG. 8 includes an acquisition unit 201, an extraction unit 202, a calculation unit 203, a verification unit 204, a notification unit 205, a transmission control unit 206, and a storage A unit 207 and an authentication unit 208 are provided. FIG. 9 shows an example of main components related to the present embodiment among the components provided in the outgoing mail server 210 shown in FIG.

  The extraction unit 202 has the same function as the extraction unit 102 shown in FIG.

  The calculation unit 203 has the same function as the calculation unit 103 shown in FIG.

  The verification unit 204 has the same function as the verification unit 104 illustrated in FIG.

  The notification unit 205 has the same function as the notification unit 105 shown in FIG.

  The transmission control unit 206 has the same function as the transmission control unit 106 shown in FIG.

  The authentication unit 208 authenticates the user who is operating the communication terminals 500-1 to 500-n. At this time, the authentication unit 208 compares the authentication information transmitted from the communication terminals 500-1 to 500-n with the authentication information stored in the storage unit 207 to authenticate the user. This authentication information is user identification information such as a user's e-mail address and member ID, and a password. A specific authentication method may be the same as a general method.

  The storage unit 207 stores authentication information for authenticating the user who is operating the communication terminals 500-1 to 500-n, in addition to the information stored in the storage unit 107 illustrated in FIG.

  FIG. 10 is a diagram illustrating an example of authentication information stored in the storage unit 207 illustrated in FIG. 9.

  As shown in FIG. 10, the storage unit 207 shown in FIG. 9 stores an email address, a member ID, and a password as authentication information. These are pre-stored.

  When the authentication unit 208 succeeds in authenticating the user using the authentication information stored in the storage unit 207, the acquisition unit 201 acquires an e-mail transmitted from the communication terminals 500-1 to 500-n.

  Hereinafter, an e-mail monitoring method in the outgoing mail server 210 shown in FIG. 8 will be described.

  FIG. 11 is a flowchart for explaining an example of an electronic mail monitoring method in outgoing mail server 210 shown in FIG.

  First, when authentication information (member ID or email address and password) is transmitted from the communication terminals 500-1 to 500-n, the authentication unit 208 is stored in advance in the transmitted authentication information and the storage unit 207. The user is authenticated by collating with existing authentication information (step S21).

  When the authentication unit 208 succeeds in authentication, the transmission mail server 210 receives the electronic mail transmitted from the communication terminals 500-1 to 500-n. The acquisition unit 201 acquires the received electronic mail (step S22). Subsequently, the extraction unit 202 extracts the IP address of the transmission source from the e-mail acquired by the acquisition unit 201 or connection processing (for example, an SMTP session) with the communication terminals 500-1 to 500-n (Step S1). S23). The extraction unit 202 writes the extracted IP address and the e-mail address or member ID used for authentication by the authentication unit 208 (hereinafter, described by taking the member ID as an example) in the storage unit 207 in association with the date / time information. (For example, association shown in FIG. 4). The date and time information includes the date and time when the outgoing mail server 210 received the email, the date and time when the outgoing mail server 210 sent the email, the date and time when the acquisition unit 201 acquired the email, and the storage unit 207 stored the association. Indicates the date and time.

  Then, the calculation unit 203 calculates the unique number of IP addresses extracted by the extraction unit 202 per unit time for each member ID (step S24). Subsequently, the verification unit 204 determines whether the unique number of IP addresses for each member ID calculated by the calculation unit 203 has exceeded a preset first threshold value (step S25).

  When the verification unit 204 determines that the unique number of IP addresses for each member ID calculated by the calculation unit 203 has exceeded the first threshold, the notification unit 205 may have sent a junk mail (spoofed mail). A notification indicating the fact (first notification) is sent to the administrator terminal 400 that is the notification destination (step S26). This notification includes the mail address of the corresponding sender. Further, the IP address and date / time information of the transmission source may be included in this notification.

  When the verification unit 204 determines that the unique number of IP addresses for each member ID calculated by the calculation unit 203 has exceeded the first threshold, the transmission control unit 206 determines from the email address corresponding to the corresponding member ID. The transmission of the transmitted e-mail may be stopped (step S27). On the other hand, if the verification unit 204 determines that the unique number of IP addresses for each member ID calculated by the calculation unit 203 does not exceed the first threshold, the transmission control unit 206 corresponds to the corresponding member ID. The electronic mail transmitted from the mail address is transmitted (step S28).

  Further, as in the first embodiment, the determination criterion for spam mail (spoofed mail) is not limited to the unique number of IP addresses, but the country of the transmission source may be added.

  Hereinafter, an e-mail monitoring method using country information in the outgoing mail server 210 shown in FIG. 8 will be described.

  FIG. 12 is a flowchart for explaining an example of an electronic mail monitoring method using country information in the outgoing mail server 210 shown in FIG.

  First, when authentication information (member ID or email address and password) is transmitted from the communication terminals 500-1 to 500-n, the authentication unit 208 is stored in advance in the transmitted authentication information and the storage unit 207. The user is authenticated by collating with existing authentication information (step S31).

  When the authentication unit 208 succeeds in authentication, the transmission mail server 210 receives the electronic mail transmitted from the communication terminals 500-1 to 500-n. The acquisition unit 201 acquires the received electronic mail (step S32). Subsequently, the extraction unit 202 extracts the transmission source IP address from the email acquired by the acquisition unit 201 (step S33). The extraction unit 202 writes the extracted IP address and the mail address or member ID used for authentication by the authentication unit 208 in the storage unit 207 in association with the date / time information. This date / time information is the same as that which the extraction unit 202 writes in the storage unit 207 after step S23.

  Then, the calculation unit 203 calculates the unique number of IP addresses extracted by the extraction unit 202 in unit time for each member ID (step S34). Subsequently, the verification unit 204 determines whether the unique number of IP addresses for each member ID calculated by the calculation unit 203 has exceeded a preset first threshold value (step S35).

  When the verification unit 204 determines that the unique number of IP addresses for each member ID calculated by the calculation unit 203 has exceeded the first threshold, the calculation unit 203 stores the IP address extracted by the extraction unit 202 and stored in unit time Based on the country information stored in the unit 207, the country information corresponding to the IP address is extracted, and the unique number of the country of transmission in a unit time is calculated for each member ID (step S36). Subsequently, the verification unit 204 determines whether or not the country unique number for each member ID calculated by the calculation unit 203 exceeds a preset second threshold value (step S37).

  When the verification unit 204 determines that the country unique number for each member ID calculated by the calculation unit 203 has exceeded the second threshold, the notification unit 205 may transmit a spam mail (spoofed mail). Is sent to the administrator terminal 400 that is the notification destination (step S38). This notification includes the mail address of the transmission source corresponding to the corresponding member ID. Further, the notification may include the IP address of the transmission source, date / time information, and country name.

  If the verification unit 204 determines that the country unique number for each member ID calculated by the calculation unit 203 has exceeded the second threshold, the transmission control unit 206 transmits from the mail address corresponding to the corresponding member ID. The transmission of the electronic mail that has been performed may be stopped (step S39). On the other hand, when the verification unit 204 determines that the country unique number for each member ID calculated by the calculation unit 203 does not exceed the second threshold, the transmission control unit 206 sends an email corresponding to the corresponding member ID. The electronic mail transmitted from the address is transmitted (step S40).

  After the process of step S33, the extraction unit 202 writes the extracted IP address and the member ID used for authentication in the storage unit 207 in association with the date / time information, and then performs the processes of steps S34 and S35. First, in step S36, the calculation unit 203 extracts country information corresponding to the IP address based on the IP address extracted by the extraction unit 202 in unit time and the country information stored in the storage unit 207. The unique number of the transmission source country per unit time may be calculated for each member ID. By doing in this way, even if the verification part 204 is a case where the unique number of the transmission source IP address for each member ID does not exceed the first threshold, the unique number of the transmission source country for each member ID It can be determined whether or not exceeds the second threshold.

  Similarly to the first embodiment, as a criterion for determining spam mail (spoofed mail), not only the country of the transmission source but also the region of the transmission source (for example, Kanto region or Asia) based on the IP address of the transmission source. If a region etc.) can be specified, that region may be used.

  As described above, by providing the function of the electronic mail monitoring apparatus 100 in the first embodiment to the outgoing mail server 210 in the second embodiment, the first embodiment is also implemented in the second embodiment. The effect similar to the effect in this form can be produced.

  In the embodiment described above, the processing for calculating the unique number of IP addresses for each email address or member ID and the processing for calculating the unique number for a country or region for each email address or member ID are performed in a predetermined unit time. May be performed every time (periodically), or may be performed every time the acquisition units 101 and 201 acquire an e-mail and the extraction units 102 and 202 extract an IP address (every time an e-mail is received). . When these processes are performed each time an e-mail is received, the e-mail address (member ID) of the e-mail that has already been received by a predetermined time (for example, 5 seconds) before the e-mail is received. , IP number and country or region unique number is calculated.

  The processing performed by each component provided in each of the electronic mail monitoring apparatus 100 and the outgoing mail server 210 described above may be performed by a logic circuit produced according to the purpose. In addition, a computer program (hereinafter referred to as a program) describing the processing contents as a procedure is recorded on a recording medium readable by each of the electronic mail monitoring apparatus 100 and the transmission mail server 210, and the program recorded on the recording medium is recorded. The electronic mail monitoring device 100 and the outgoing mail server 210 may be read and executed. The recording medium readable by each of the electronic mail monitoring apparatus 100 and the outgoing mail server 210 includes a removable recording medium such as a floppy (registered trademark) disk, a magneto-optical disk, a DVD, and a CD, as well as the electronic mail monitoring apparatus 100. In addition, it refers to a memory such as a ROM or a RAM, an HDD, or the like built in each outgoing mail server 210. The program recorded on the recording medium is read by a CPU (not shown) provided in each of the electronic mail monitoring apparatus 100 and the outgoing mail server 210, and the same processing as described above is performed under the control of the CPU. . Here, the CPU operates as a computer that executes a program read from a recording medium on which the program is recorded.

A part or all of the above embodiment can be described as in the following supplementary notes, but is not limited thereto.
(Appendix 1) An acquisition unit that acquires an email transmitted from a communication terminal;
An extraction unit that extracts user identification information indicating a user who has transmitted the e-mail and communication terminal identification information given to the communication terminal that has transmitted the e-mail from the e-mail acquired by the acquisition unit;
For each user identification information extracted by the extraction unit in unit time, a calculation unit that calculates a unique number of the communication terminal identification information;
A verification unit that determines whether the unique number of the communication terminal identification information for each of the user identification information calculated by the calculation unit exceeds a predetermined first threshold;
When the verification unit determines that the unique number of the communication terminal identification information for each user identification information calculated by the calculation unit exceeds the first threshold, a predetermined first notification is set in advance. An e-mail monitoring apparatus having a notification unit that performs notification to a notification destination.
(Supplementary Note 2) When the calculation unit determines that the unique number of the communication terminal identification information for each of the user identification information calculated by the calculation unit has exceeded the first threshold, the unit of unit time For each user identification information extracted by the extraction unit, the unique number of the country or region is calculated based on the communication terminal identification information.
The verification unit determines whether the unique number of the country or region for each user identification information calculated by the calculation unit exceeds a predetermined second threshold;
The notification unit does not perform the first notification, and the verification unit determines that the unique number of the country or region for each user identification information calculated by the calculation unit has exceeded the second threshold value. In this case, the electronic mail monitoring apparatus according to appendix 1, wherein a predetermined second notification is sent to the notification destination.
(Additional remark 3) The user identification information which the said verification part determined that the unique number of the said communication terminal identification information exceeded the said 1st threshold value, or the unique number of the said country or area exceeded the said 2nd threshold value The electronic mail monitoring apparatus according to claim 2, further comprising: a transmission control unit that stops transmission of an electronic mail having the user identification information determined as having been transmitted.
(Additional remark 4) The said acquisition part acquires the member identification information of the user who transmitted the said email from the transmission mail server connected with the said email monitoring apparatus,
The e-mail monitoring according to appendix 2 or appendix 3, wherein the calculation unit calculates a unique number of the communication terminal identification information or a unique number of the country or region for each member identification information apparatus.
(Additional remark 5) The acquisition part which acquires the email transmitted from the communication terminal,
An extraction unit that extracts user identification information indicating a user who has transmitted the e-mail and communication terminal identification information given to the communication terminal that has transmitted the e-mail from the e-mail acquired by the acquisition unit;
For each user identification information extracted by the extraction unit in unit time, a calculation unit that calculates a unique number of countries or regions corresponding to the communication terminal identification information;
A verification unit that determines whether a unique number of the country or region for each of the user identification information calculated by the calculation unit exceeds a predetermined second threshold;
When the verification unit determines that the unique number of the country or region for each user identification information calculated by the calculation unit exceeds the second threshold, a predetermined second notification is set in advance. An e-mail monitoring device having a notifying unit to be performed first.
(Supplementary note 6) Any one of Supplementary notes 1 to 5, wherein the extraction unit extracts an email address or member identification information as the user identification information, and extracts an IP address as the communication terminal identification information. The electronic mail monitoring apparatus according to item 1.
(Appendix 7) An authentication unit for authenticating a user;
A storage unit for storing authentication information for performing the authentication;
When the authentication unit succeeds in authenticating the user using authentication information stored in the storage unit, an acquisition unit that acquires an email transmitted from a communication terminal;
User identification information indicating the user who transmitted the e-mail is extracted from the authentication information, and is given to the e-mail acquired by the acquisition unit or the communication terminal that transmitted the e-mail from the connection process with the communication terminal. An extractor for extracting communication terminal identification information;
For each user identification information extracted by the extraction unit in unit time, a calculation unit that calculates a unique number of the communication terminal identification information;
A verification unit that determines whether the unique number of the communication terminal identification information for each of the user identification information calculated by the calculation unit exceeds a predetermined first threshold;
When the verification unit determines that the unique number of the communication terminal identification information for each user identification information calculated by the calculation unit exceeds the first threshold, a predetermined first notification is set in advance. A transmission mail server having a notification unit to be sent to a notification destination.
(Appendix 8) An authentication unit for authenticating a user;
A storage unit for storing authentication information for performing the authentication;
When the authentication unit succeeds in authenticating the user using authentication information stored in the storage unit, an acquisition unit that acquires an email transmitted from a communication terminal;
User identification information indicating the user who transmitted the e-mail is extracted from the authentication information, and is given to the e-mail acquired by the acquisition unit or the communication terminal that transmitted the e-mail from the connection process with the communication terminal. An extractor for extracting communication terminal identification information;
For each user identification information extracted by the extraction unit in unit time, a calculation unit that calculates a unique number of countries or regions corresponding to the communication terminal identification information;
A verification unit that determines whether a unique number of the country or region for each of the user identification information calculated by the calculation unit exceeds a predetermined second threshold;
When the verification unit determines that the unique number of the country or region for each user identification information calculated by the calculation unit exceeds the second threshold, a predetermined second notification is set in advance. An outgoing mail server having a notification unit to be sent to the destination.
(Supplementary note 9) An email monitoring method for monitoring email sent from a communication terminal,
Processing for obtaining an email sent from the communication terminal;
A process of extracting from the acquired e-mail user identification information indicating a user who transmitted the e-mail and communication terminal identification information given to the communication terminal that transmitted the e-mail;
A process of calculating a unique number of the communication terminal identification information for each extracted user identification information in a unit time;
A process of determining whether or not the unique number of the communication terminal identification information for each of the calculated user identification information exceeds a predetermined first threshold;
When it is determined that the calculated unique number of the communication terminal identification information for each user identification information exceeds the first threshold value, a process of performing a predetermined first notification to a preset notification destination is performed. Email monitoring method.
(Supplementary note 10) An electronic mail monitoring method for monitoring an electronic mail transmitted from a communication terminal,
Processing for obtaining an email sent from the communication terminal;
A process of extracting from the acquired e-mail user identification information indicating a user who transmitted the e-mail and communication terminal identification information given to the communication terminal that transmitted the e-mail;
For each of the extracted user identification information in unit time, a process of calculating a unique number of countries or regions corresponding to the communication terminal identification information;
A process of determining whether the calculated unique number of the country or region for each user identification information exceeds a predetermined second threshold;
An electronic device that performs a process of performing a predetermined second notification to a preset notification destination when it is determined that the calculated unique number of the country or region for each user identification information exceeds the second threshold value Mail monitoring method.
(Supplementary note 11)
A procedure for obtaining an email sent from a communication terminal;
A procedure for extracting, from the acquired e-mail, user identification information indicating a user who has transmitted the e-mail and communication terminal identification information given to the communication terminal that has transmitted the e-mail;
A procedure for calculating a unique number of the communication terminal identification information for each extracted user identification information in a unit time;
Determining whether the calculated unique number of the communication terminal identification information for each of the user identification information exceeds a predetermined first threshold;
When it is determined that the calculated unique number of the communication terminal identification information for each user identification information exceeds the first threshold, a predetermined first notification is executed to a preset notification destination. Program to let you.
(Supplementary note 12)
A procedure for obtaining an email sent from a communication terminal;
A procedure for extracting, from the acquired e-mail, user identification information indicating a user who has transmitted the e-mail and communication terminal identification information given to the communication terminal that has transmitted the e-mail;
A procedure for calculating a unique number of countries or regions corresponding to the communication terminal identification information for each of the extracted user identification information in unit time;
A procedure for determining whether or not the calculated unique number of the country or region for each user identification information exceeds a predetermined second threshold;
A step of performing a predetermined second notification to a preset notification destination when it is determined that the calculated unique number of the country or region for each user identification information exceeds the second threshold value Program for.

DESCRIPTION OF SYMBOLS 100 Electronic mail monitoring apparatus 101,201 Acquisition part 102,202 Extraction part 103,203 Calculation part 104,204 Verification part 105,205 Notification part 106,206 Transmission control part 107,207 Storage part 200,210 Transmission mail server 208 Authentication part 300 received mail server 400 administrator terminal 500-1 to 500-n communication terminal

Claims (10)

An acquisition unit that acquires an e-mail transmitted from a communication terminal and acquires member identification information of the user who transmitted the e-mail from an e-mail server connected to the e-mail monitoring device ;
An extraction unit configured to extract the email or al the acquisition unit has acquired, the communication terminal identification information assigned to the communication terminal that has transmitted the e-mail,
For each member identification information acquired by the acquisition unit in unit time, a calculation unit that calculates a unique number of the communication terminal identification information;
A verification unit that determines whether the unique number of the communication terminal identification information for each member identification information calculated by the calculation unit exceeds a predetermined first threshold;
The verification unit includes a notification unit that performs a predetermined first notification including the member identification information determined that the unique number of the communication terminal identification information has exceeded the first threshold to a preset notification destination. Email monitoring device. An acquisition unit that acquires an e-mail transmitted from a communication terminal and acquires member identification information of the user who transmitted the e-mail from an e-mail server connected to the e-mail monitoring device ;
Email or al acquired by the acquiring unit, an extraction unit to extract a communication terminal identification information assigned to the communication terminal that has transmitted the e-mail,
For each member identification information acquired by the acquisition unit in unit time, a calculation unit that calculates a unique number of countries or regions corresponding to the communication terminal identification information;
A verification unit that determines whether the unique number of the country or region for each member identification information calculated by the calculation unit exceeds a predetermined second threshold;
An electronic device comprising: a notifying unit configured to perform a predetermined second notification including the member identification information determined by the verification unit that the unique number of the country or region exceeds the second threshold value to a preset notification destination Mail monitoring device. The electronic mail monitoring apparatus according to claim 1 or 2,
User identification information that the verification unit has determined that the unique number of the communication terminal identification information has exceeded the first threshold value, or use that has been determined that the unique number of the country or region has exceeded the second threshold value An e-mail monitoring apparatus comprising: a transmission control unit that stops transmission of an e-mail having a sender identification information as a transmission source. An authentication unit for authenticating the user;
A storage unit for storing authentication information for performing the authentication;
When the authentication unit succeeds in authenticating the user using authentication information stored in the storage unit, an acquisition unit that acquires an email transmitted from a communication terminal;
User identification information indicating the user who transmitted the e-mail is extracted from the authentication information, and is given to the e-mail acquired by the acquisition unit or the communication terminal that transmitted the e-mail from the connection process with the communication terminal. An extractor for extracting communication terminal identification information;
For each user identification information extracted by the extraction unit in unit time, a calculation unit that calculates a unique number of the communication terminal identification information;
A verification unit that determines whether the unique number of the communication terminal identification information for each of the user identification information calculated by the calculation unit exceeds a predetermined first threshold;
A notifying unit configured to perform a predetermined first notification including the user identification information, which is determined that the unique number of the communication terminal identification information exceeds the first threshold, to a preset notification destination; Yes, and
The extraction unit is a transmission mail server that extracts an email address or member identification information as the user identification information . An authentication unit for authenticating the user;
A storage unit for storing authentication information for performing the authentication;
When the authentication unit succeeds in authenticating the user using authentication information stored in the storage unit, an acquisition unit that acquires an email transmitted from a communication terminal;
User identification information indicating the user who transmitted the e-mail is extracted from the authentication information, and is given to the e-mail acquired by the acquisition unit or the communication terminal that transmitted the e-mail from the connection process with the communication terminal. An extractor for extracting communication terminal identification information;
For each user identification information extracted by the extraction unit in unit time, a calculation unit that calculates a unique number of countries or regions corresponding to the communication terminal identification information;
A verification unit that determines whether a unique number of the country or region for each of the user identification information calculated by the calculation unit exceeds a predetermined second threshold;
And a notifying unit configured to perform a predetermined second notification including the user identification information determined that the unique number of the country or region has exceeded the second threshold value to a preset notification destination. And
The extraction unit is a transmission mail server that extracts an email address or member identification information as the user identification information . In the outgoing mail server according to claim 4 or 5 ,
Sending mail server, wherein the extraction unit, for extracting the IP address as the previous SL communication terminal identification information. An email monitoring method for monitoring email sent from a communication terminal,
Processing for obtaining an email sent from the communication terminal;
A process of acquiring member identification information of the user who transmitted the e-mail from an e-mail server connected to the e-mail monitoring device;
A process of extracting the acquired e-mail or, et al., The communication terminal identification information assigned to the communication terminal that has transmitted the e-mail,
For each of the acquired member identification information in a unit time, a process of calculating a unique number of the communication terminal identification information or a unique number of a country or region corresponding to the communication terminal identification information ;
A process of determining whether the calculated unique number of the communication terminal identification information for each member identification information or the unique number of the country or region exceeds a predetermined threshold ;
E-mail monitoring for performing a predetermined notification including the member identification information determined that the unique number of the communication terminal identification information or the unique number of the country or region exceeds the threshold value to a preset notification destination Method. An e-mail monitoring method for a sending mail server for sending an e-mail sent from a communication terminal,
A process of authenticating the user;
When the user is successfully authenticated using the authentication information stored in the storage unit, a process of obtaining an e-mail transmitted from the communication terminal;
A process of extracting user identification information indicating the user who transmitted the e-mail from the authentication information ;
A process of extracting the acquired e-mail or the communication terminal and the connection process communication terminal identification information assigned to the communication terminal transmitting the electronic mail from,
For each user identification information extracted by the extracting unit in a unit time, a process of calculating a unique number of countries or regions corresponding to the unique number or the communication terminal identification information of the communication terminal identification information,
Unique number of unique numbers or the country or region of the communication terminal identification information for each said user identification information issued calculated and the process of determining whether more than a predetermined threshold value,
A process of performing a predetermined notification including the user identification information determined that the unique number of the communication terminal identification information or the unique number of the country or region exceeds the threshold , to a preset notification destination ;
Have
In the process of extracting the user identification information, an e-mail address or member identification information is extracted as the user identification information
An e-mail monitoring method characterized by the above . On the computer,
A procedure for obtaining an email sent from a communication terminal;
A process of acquiring member identification information of the user who transmitted the e-mail from an e-mail server connected to the e-mail monitoring device;
A step of extracting the acquired e-mail or, et al., The communication terminal identification information assigned to the communication terminal that has transmitted the e-mail,
A procedure for calculating a unique number of the communication terminal identification information or a unique number of countries or regions corresponding to the communication terminal identification information for each of the acquired member identification information in a unit time;
Determining whether the calculated unique number of the communication terminal identification information for each member identification information or the unique number of the country or region exceeds a predetermined threshold ;
A procedure for performing a predetermined notification including the member identification information determined that the unique number of the communication terminal identification information or the unique number of the country or region exceeds the threshold to a preset notification destination program. A program for causing a computer to send an e-mail sent from a communication terminal ,
A procedure for authenticating the user;
If the user is successfully authenticated using the authentication information stored in the storage unit, a procedure for obtaining an e-mail transmitted from the communication terminal;
A procedure for extracting user identification information indicating a user who has transmitted the e-mail from the authentication information ;
A procedure for extracting the communication terminal identification information given to the communication terminal that transmitted the e-mail from the acquired e-mail or the connection process with the communication terminal;
For each user identification information extracted by the extracting unit in a unit time, a step of calculating a unique number of countries or regions corresponding to the unique number or the communication terminal identification information of the communication terminal identification information,
Unique number of unique numbers or the country or region of the communication terminal identification information for each said user identification information issued calculated and the procedure for determining whether more than a predetermined threshold value,
A procedure of performing a predetermined notification including the user identification information determined that the unique number of the communication terminal identification information or the unique number of the country or region has exceeded the threshold , to a preset notification destination ;
Have
In the procedure for extracting the user identification information, an email address or member identification information is extracted as the user identification information.
A program characterized by that .

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