JP2003115878A - Mail server and mail server program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To raise a caution on troublesome mail or disguise mail to a recipient. SOLUTION: When electronic mail 3 received by a mail server 2 is judged as troublesome mail or disguise mail, the mail server 2 prepares caution mail and transmits it to a receiving terminal 11. In such a case, the electronic mail 3 can also be transmitted together by setting of the receiving terminal. The user of the receiving terminal 11 receives the caution mail an can determine whether the mail is to be read or to be acquired.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mail server and a mail server program for delivering transferred mail to a destination.

[0002]

2. Description of the Related Art Recently, it has become possible to send and receive messages by electronic mail via a computer network such as the Internet. E-mail, which is also called E-mail, has the advantage of not being restricted in terms of time and space because information is automatically stored in the receiving mailbox even when the other party is absent. Also,
Electronic mail using the Internet has great potential because it can be directly sent to hundreds of millions of people around the world. Further, data such as graphics, programs, moving images, and voices can be attached to the electronic mail and transmitted.
Recently, this electronic mail can be transmitted / received from a personal computer via the Internet to / from a mobile device in a mobile communication network.

[0003]

[Problems to be Solved by the Invention] However, with regard to electronic mail, spoofing such as direct mail or mail containing viruses, and spoofing other than etiquette such as slander, slander, harassment, etc. You can easily send an email. As described above, the electronic mail has a problem that it is vulnerable to spam mail and spoof mail. In order to solve this, the mail recipient registers certain conditions such as the mail address that he / she wants to refuse to receive in the receiving server, the upper limit of the mail capacity, etc., and deletes the mail that meets the conditions on the mail server. ing. However, there is a problem in that the mail may be necessary because the mail server deletes the mail without making a judgment on whether the mail recipient needs the mail.

When a large amount of the same mail is received,
It is proposed that the receiving server receives the judgment whether it is annoying from the users who read it and, if a certain number or more of users judge that it is annoying, does not send the mail to the remaining users (special feature). (See Kaihei 10-74172). Even in this case, there is a problem that the mail server deletes the mail because the mail recipient does not judge whether the mail is necessary or not. In addition, there is a problem that the software needs to be changed by the mail recipient. Furthermore, when sending an e-mail, only the header information is sent from the sending server to the receiving server, and if the e-mail reply to the sender address in the header information is possible, send an e-mail permitting the sending of the e-mail text to the sending server. Has also been proposed (see Japanese Patent Application Laid-Open No. 8-32616). This proposal has a problem that if the mail reply cannot be made, the mail to be received and the mail not to be received are not uniformly distributed without being distinguished. Further, there is a problem that it is difficult to apply the technique in the Internet world where a variety of mail servers coexist because the sending server and the receiving server need to cooperate with each other.

Therefore, an object of the present invention is to provide a mail server and a mail server program capable of warning a recipient of junk mail or spoofing mail.

[0006]

In order to achieve the above object, the mail server of the present invention comprises processing means for executing mail delivery processing for delivering the transferred mail to the destination of the mail. In the mail server, the processing means detects whether or not the delivery is permitted by checking the recipient address of the forwarded email and the title of the email, and the delivery is not permitted. When is detected, a warning mail indicating that an undeliverable mail is received is delivered to the destination of the mail. Further, another mail server of the present invention that can achieve the above object is a mail server including a processing unit that executes a mail delivery process for delivering a forwarded mail to a destination of the mail. The processing means detects whether or not the mail is deliverable by checking the sender and recipient addresses in the communication history of the forwarded mail, and the mail that is not deliverable is detected. At this time, a warning mail indicating that a mail whose delivery is not allowed is received is delivered to the destination of the mail.

Still another mail server of the present invention that can achieve the above object is a mail including a processing means for executing a mail delivery process for delivering a forwarded mail to a destination of the mail. In the server, the processing means detects whether or not the delivery is acceptable by checking the addresses of the sender and the recipient in the communication history of the forwarded email and the subject of the email. However, when an undeliverable mail is detected, a warning mail indicating that an undeliverable mail is received is delivered to the destination of the mail.

Further, in the above mail server of the present invention, the processing means, when the delivery request of the mail is received from the destination to which the warning mail is transmitted, delivers the mail to the destination. May be. Further, in the above-mentioned mail server of the present invention, the processing means, when a mail that is not allowed to be delivered is detected, sends a warning mail indicating that the mail is not allowed to be delivered and the mail together with the destination of the mail. It may be delivered to. Furthermore, in the above-mentioned mail server of the present invention, the processing means detects whether or not the current time zone is a time zone during which the delivery is permitted, and when the delivery time is detected as a time zone during which the delivery is not permitted. May wait until the delivery time arrives before delivery.

Next, the mail server program of the present invention which can achieve the above object can cause the mail server to execute a mail delivery process for delivering the transferred mail to the destination of the mail. A mail server program, which detects whether or not the mail is deliverable by checking the address of the recipient of the transferred mail and the title of the mail, and a delivery step in the detecting step. When an email that is not allowed is detected, a creating step is created to create a warning email indicating that an email that is not allowed to be delivered is received, and the alert email created in the creating step is delivered to the destination of the email. And a delivery step to perform.

Further, another mail server program of the present invention which can achieve the above object is to cause the mail server to execute a mail delivery process for delivering the transferred mail to the destination of the mail. A mail server program capable of detecting a sender's address and a recipient's address in the communication history of the transferred mail, thereby detecting whether or not the mail is deliverable, and in the detecting step, ,
When an email that is not allowed to be delivered is detected, a warning email indicating that an email that cannot be delivered is received is created, and the alert email created at the creating step is sent to the destination of the email. And a delivery step for delivering.

Further, still another mail server program of the present invention which can achieve the above object, causes the mail server to execute a mail delivery process for delivering the transferred mail to the destination of the mail. Is a mail server program capable of performing, and detects whether or not the mail is acceptable for delivery by checking the addresses of the sender and the recipient in the communication history of the transferred mail, and the title of the mail. A detection step, a creation step of creating a warning mail indicating that an undeliverable mail is received when an undeliverable mail is detected in the detection step, and a creation step created in the creation step And a delivery step for delivering a warning email to the destination of the email. It is.

The mail server program of the present invention further comprises a mail delivery step of delivering the mail to the destination when the delivery request of the email is received from the destination to which the warning email is delivered. May be. Further, in the above mail server program of the present invention, when a mail that is not allowed to be delivered is detected, the warning mail is replaced with a delivery step of delivering to the destination of the email, and the email is not allowed to be delivered. A mail delivery step of delivering both the warning mail and the mail shown to the destination of the mail may be provided. Furthermore, in the above mail server program of the present invention, when delivering, it is detected whether or not the current time zone is a time zone during which delivery is permitted, and if delivery is detected in a time zone during which delivery is not permitted, delivery is performed. The method may further include a step of waiting until an allowable time period is reached and delivering the product.

According to the present invention as described above, when an undeliverable mail is detected, a warning mail indicating that the undeliverable mail is received is delivered to the destination of the mail. Therefore, the destination user can know that the junk mail or the spoofing mail is coming. Therefore, it is possible to select not to receive the mail as it is or to discard the received mail without opening it, according to the judgment of the user. Further, since it is possible to prevent the delivery from being performed outside the time period when the delivery is allowed, it is possible to refuse the reception of the mail during a busy time period, midnight, or the like.

Further, according to the present invention, it is sufficient to change the program of only the mail server of the target system. For example, among the various types of mail servers mixed on the Internet, it is only necessary to change the program of the receiving mail server of the target system, and the mail server or terminal outside the system does not need to change it. It can be easily implemented. Furthermore, if only the warning mail is received instead of the mail itself, the communication charge of the mail can be reduced. Further, unwanted mail or spoofing mail can be distinguished from necessary mail, and it is possible to prevent necessary mail from being buried. Furthermore, in the case of a spoofing email, it is possible to prevent a reply to an unintended address.

[0015]

FIG. 1 shows a schematic configuration of a mail delivery system including a mail server according to an embodiment of the present invention. In the example shown in FIG. 1, a mail sender using the personal computer 10 sends a mail to a mail receiver who is a user of the receiving terminal 11 such as a mobile phone. The electronic mail 3 transmitted from the personal computer 10 is received by the mail server 1 and transferred to the next mail server 2. The mail server 2 is a mail server according to the embodiment of the present invention. If the mail server 2 detects whether it is junk mail or spoofing mail, and if it is detected as junk mail or spoofing mail, a warning mail is sent. 4 is created. This warning mail 4 is transmitted to the receiving terminal 11, but the warning mail 4 created as shown in FIG. 1 and the transferred electronic mail 3 are received by the receiving terminal 1.
1 to both the setting for sending the warning mail 4 and the setting for sending only the warning mail 4 to the receiving terminal 11,
The mail server 2 can be set in advance for each receiving terminal.

Junk mail means that when the mail address or domain name registered by the user of the receiving terminal 11 as unsolicited mail and the sender address or sender's domain name of the electronic mail 3 match. Email 3
Should be judged as junk mail. For the sender's email address and sender's domain name of Email 3, see Email 3.
Can be detected from the mail header 3a. The sender address is described in the lowest From line in the mail header 3a. Further, it may be determined whether or not the email is a junk email by performing filtering based on the title described in the Subject line in the email header 3a of the email 3.

The spoofing mail is a mail in which the address is spoofed and the other person is spoofed. Electronic mail is usually delivered via several mail servers as shown in FIG. Then, the communication history information is added and described in the mail header of the electronic mail delivered each time it passes through the mail server. In this case, the From line in the mail header describes the sender's address of the sender, and the Received line describes the host name and domain name of the received mail server. Received line will be added to the mail header. In this case, since it is added to the top, the top description is the latest communication history. In this case, the domain name included in the address of the mail sender that indicates the sender described in the From line of the email and the domain name described in the Received line of the mail server that received the mail from the mail sender Should match. However, as shown in FIG. 1, in the spoofing email, the domain name 11.xx included in the address aa@11.xx described in the From line indicating the email sender 10 in the email header 3a of the email 3 and the email server The domain name 22.yy described in the Received line indicating the recipient in 1 does not match.

As described above, by checking the communication history information in the mail header, it is possible to determine whether the mail is a spoofed mail. When the email 3 received by the mail server 2 is determined to be a junk email or a spoofing email, a warning email 4 is created and transmitted to the receiving terminal 11. As shown in FIG. 1, the warning mail 4 is a mail having the content of “Caution for spoofing” or “Caution for junk mail”. The warning mail 4 is read by the mail recipient who is the user of the receiving terminal 11, You can know that you are getting junk mail or spoofing mail. After receiving the warning mail 4, the mail recipient can judge for himself whether to read the electronic mail 3 or not. If it is determined that the warning e-mail is read, and if the warning mail 4 and the e-mail 3 are not delivered to the receiving terminal 11 at the same time, the receiving terminal 1
The mail recipient who is the first user requests the mail server 2 to deliver the electronic mail 3. In the To line of the mail header 3a, the destination email address is described. If the destination email address is dd@99.zz as shown in FIG. 1, dd is the user name and 99 .zz
Is the domain name. Also, the sender of the mail is PC 1
The number of users is not limited to 0, and any electronic device such as an information device or a mobile phone in which a mailer program is installed can be a mail sender. The same applies to mail recipients.

Next, FIG. 2 shows a configuration example of the mail server 2 according to the embodiment of the present invention. In FIG. 2, the CPU
A central processing unit 20 controls a mail delivery process in the mail server 2 by executing the mail server program according to the present invention.
The timer 21 is a timer that indicates an elapsed time during operation and generates a timer interrupt at a specific interval. ROM
Reference numeral 22 denotes a program executed by the CPU 20 for processing of delivering unsolicited mail and spoofing mail, and SMTP (Simple Mail Transfer Proto) for sending and receiving electronic mail.
col), POP3 (Post Office Protocol Version 3)
Or IMAP (Internet Messaging Access Protoc
ol) and other mail server programs, and ROM (Read Only Me) that stores various data.
mory). RAM23 is the main memory, CP
RAM (Random A) where the work area of U20 is set
ccess Memory).

The keyboard 24 is provided with a large number of keys for inputting signals such as numbers, characters (katakana, alphabet), symbol keys and function keys.
The display 25 is a display device that displays characters and figures according to the operation of the keyboard 24 and the mouse. The network interface 26 is, for example, an Ethernet (registered trademark) interface, and is connected to other nodes such as the mail server 1 on the network by the network interface 26. The HDD 27 is a large-capacity hard disk storage device, and various programs including a mail server program and mail data can be stored in the HDD 27. That is, H
The DD 27 can be used as a mailbox. Further, when the mail server program is stored in the HDD 27, the version of the mail server program can be easily upgraded. The blocks are connected to each other via a bus 28.

Next, FIG. 3 is a flowchart of a mail server program executed by the mail server 2 according to the present invention.
, And the flowchart will be described below. However, here, the received e-mail is represented as “main mail” in order to distinguish it from the warning mail. It is assumed that the mail server 2 receives the main mail addressed to the receiving terminal 11 (step S1). Then, in step S2, the mail header of this mail is checked by the mail server 2 to determine whether it is a junk mail or a spoofing mail. In this case, if the mail address or domain name registered by the user of the receiving terminal 11 as junk mail matches the sender's mail address of this mail or the domain name included in the sender's address, this mail will be junk. Judge as mail. Also, the domain name included in the email address described in the From line that indicates the email sender in the email header of this email, and Rece that indicates the recipient at the email server that received the email.
Look at the match with the domain name described in the ived line, and if it does not match, determine that it is a spoofed email.

When it is determined in step S2 that the mail is a junk mail or a spoofing mail, it is judged in step S4 whether or not the warning mail is set to be transmitted to the receiving terminal 11 which is the destination. . This setting is set so that the user can set the mail server 2 for each receiving terminal. Here, if the warning mail is set to be sent to the receiving terminal 11 which is the destination, the process proceeds to step S5, and this mail is stored in the HDD 27. Next, in step S6, the mail server 2 creates a warning mail having the content such as "Caution for spoofing" or "Caution for junk mail" whose destination is the receiving terminal 11. Further, in step S10, it is determined whether or not the transmission time zone is set. The setting of the transmission time zone is a setting for preventing the mail from being delivered in a busy time zone or a time zone such as midnight, and may be set in the mail server 2 by the user for each receiving terminal. it can.

Here, the setting of the transmission time zone is set by the receiving terminal 11
If not, step S1
In step 3, it is determined whether or not only the warning mail is set to be transmitted. The setting for sending only the warning mail can be set in the mail server 2 by the user for each receiving terminal. If it is determined that the receiving terminal 11 is not set to send only the warning mail,
In step S17, the main mail read from the HDD 27 and the created warning mail are transmitted to the receiving terminal 11. If it is determined in step S13 that the receiving terminal 11 is set to send only the warning mail, only the warning mail created by branching to step S14 is sent to the receiving terminal 11. Then, when the receiving terminal 11 receiving this warning mail sends a request for sending this mail to the mail server 2 (step S15), the mail server 2 reads this mail from the HDD 27 and sends it to the receiving terminal 11 ( Step S16).

If the mail is not judged to be junk mail or spoofing mail in step S2,
This mail is sent to the receiving terminal 11 by branching to step S3. Further, if it is determined in step S4 that the receiving terminal 11 is not set to send a warning mail, the process branches to step S7 to determine whether it is set to delete junk mail or spoofing mail. To be done. This setting is set so that the user can set the mail server 2 for each receiving terminal. Here, if it is determined that the receiving terminal 11 is set to delete the junk mail or the spoofed mail, step S
Proceed to step 9 and this email will be deleted. Also, step S7
When it is determined that the receiving terminal 11 is not set not to delete the junk mail or the spoofing mail, the process branches to step S8 and the mail is transmitted to the receiving terminal 11.

Furthermore, when it is determined in step S10 that the setting of the transmission time zone is set in the receiving terminal 11, the warning mail created by branching to step S11 is temporarily stored in the HDD 27. Then, in step S12, it is determined whether or not the current time is a time period during which transmission is permitted. Here, if the current time is within the transmission allowable time zone range, the process proceeds to step S13, and the processing after step S13 described above is performed and only the warning mail or the main mail and the warning mail are transmitted to the receiving terminal 11. Become so. If it is determined that the current time is outside the allowable transmission time zone range, the process waits until the time is within the allowable transmission time zone range.

As described above, in the mail server 2 that executes the mail server program, when it is determined that the mail is a junk mail or a spoofed mail, the user of the set receiving terminal is warned.
For this reason, after receiving the warning, it becomes possible to determine whether or not to receive the mail according to the judgment of the user. At this time, if you choose not to get the email, you only need to receive the alert email, so you can reduce the communication cost if there is a difference in the data amount between the alert email and the spoofed email / spam email. . Also, instead of deleting all the mails judged to be junk mails or spoofed mails uniformly, only the mails for the users who have set the deletion will be deleted. In addition, you can select to receive only the necessary mail after you see the warning mail, or the warning mail is sent just before spoofing mail / junk mail, so you can distinguish it from the necessary mail. Like Therefore, it becomes possible to prevent the necessary mail from being buried in spoofing mail or junk mail.

Furthermore, when the sender address (described in the From line) is spoofed, a warning mail as a spoofing mail can be received, so that a reply to an unintended address can be prevented. You will be able to. Furthermore, the system can be constructed by changing the mail server program in the mail server, and it is not necessary to change the program in another server or the receiving terminal. In particular, when the receiving terminal is a mobile phone, when changing the built-in program, the user cannot change the program, and thus it is difficult to change the program. Furthermore, it is possible to add specific conditions such as rejecting spoofed / unsolicited emails and receiving only other emails during busy hours or late night when you want to avoid receiving emails. . As a result, it is possible to make a selection such that only necessary e-mails are received during busy hours and sleeping hours, and other e-mails are received during times when there is a margin.

[0028]

As described above, according to the present invention, when an undeliverable mail is detected, a warning mail indicating that the undeliverable mail is received is delivered to the destination of the mail. Therefore, the destination user can know that the junk mail or the spoofing mail is coming. Therefore, it is possible to select not to receive the mail as it is or to discard the received mail without opening it, according to the judgment of the user. Further, since it is possible to prevent the delivery from being performed outside the time period when the delivery is allowed, it is possible to refuse the reception of the mail during a busy time period, midnight, or the like.

Further, according to the present invention, it is sufficient to change the program of only the mail server of the target system. For example, among the various types of mail servers mixed on the Internet, it is only necessary to change the program of the receiving mail server of the target system, and the mail server or terminal outside the system does not need to change it. It can be easily implemented. Furthermore, if only the warning mail is received instead of the mail itself, the communication charge of the mail can be reduced. Further, unwanted mail or spoofing mail can be distinguished from necessary mail, and it is possible to prevent necessary mail from being buried. Furthermore, in the case of a spoofing email, it is possible to prevent a reply to an unintended address.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of a mail delivery system including a mail server according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration example of a mail server according to the exemplary embodiment of the present invention.

FIG. 3 is a flowchart of a mail server program executed by the mail server according to the present invention.

[Explanation of symbols]

1 mail server, 2 mail server, 3 electronic mail, 3a mail header, 4 warning mail, 10 personal computer, 11 receiving terminal, 20 CPU, 21 timer,
22 ROM, 23 RAM, 24 keyboard, 25
Display, 26 network interface,
27 HDD, 28 bus

Continued front page    (72) Inventor Teruya Fujii             4-7-1, Hatchobori, Chuo-ku, Tokyo Japan             Telecom Co., Ltd. F-term (reference) 5K030 GA15 HA06 HC01 LD13

Claims (12)

[Claims] 1. A mail server comprising processing means for executing mail delivery processing for delivering a transferred mail to a destination of the mail, wherein the processing means is a recipient of the transferred mail. By checking the address and the subject of the mail, it is detected whether the mail is acceptable for delivery,
A mail server characterized in that when an undeliverable mail is detected, a warning mail indicating that undeliverable mail is received is delivered to the destination of the mail. 2. A mail server comprising processing means for executing mail delivery processing for delivering a transferred mail to a destination of the mail, wherein the processing means is a communication history of the transferred mail. By checking the sender's and recipient's addresses in, it is possible to detect whether the mail is acceptable for delivery,
A mail server characterized in that when an undeliverable mail is detected, a warning mail indicating that undeliverable mail is received is delivered to the destination of the mail. 3. A mail server comprising processing means for executing mail delivery processing for delivering a transferred mail to a destination of the mail, wherein the processing means is a communication history of the transferred mail. By checking the sender's and recipient's addresses in, and the subject of the mail, it is detected whether or not the mail is allowed to be delivered, and if the mail not to be delivered is detected, the delivery is allowed. A mail server characterized by delivering a warning mail indicating that an undelivered mail has been received to the destination of the mail. 4. The processing means, when a delivery request for the mail is received from a destination to which the warning mail has been transmitted, delivers the mail to the destination. The mail server according to any one of 1 to 3. 5. The processing means, when an undeliverable mail is detected, delivers the warning mail indicating the undeliverable mail and the mail together to the destination of the mail. The mail server according to any one of claims 1 to 3, wherein 6. The processing means detects whether or not the current time zone is a time zone during which the delivery is permitted at the time of delivery, and the delivery is permitted when it is detected as a time zone during which the delivery is not permitted. The mail server according to any one of claims 1 to 5, wherein the mail server waits until a certain time zone is reached for delivery. 7. A mail server program capable of causing a mail server to execute a mail delivery process for delivering a forwarded mail to a destination of the forwarded mail, and an address of a recipient of the forwarded mail. And a detection step of detecting whether or not the delivery is permitted by checking the subject of the email, and in the detection step, if the delivery is not permitted, the delivery is not permitted. A mail comprising at least a creating step for creating a warning mail indicating that the mail has been received, and a delivery step for delivering the warning mail created in the creating step to the destination of the mail. Server program. 8. A mail server program capable of causing a mail server to execute a mail delivery process for delivering a transferred mail to a destination of the mail, and sending the transferred mail in a communication history. A detection step of detecting whether or not the mail is acceptable for delivery by checking the original and recipient addresses, and if the email that is not acceptable for delivery is detected in the detecting step, the delivery is not permitted. At least a creating step for creating a warning mail indicating that the mail has been received and a delivery step for delivering the warning mail created in the creating step to the destination of the mail are provided. Mail server program. 9. A mail server program capable of causing a mail server to execute a mail delivery process for delivering a forwarded mail to a destination of the forwarded mail, the sending in a communication history of the forwarded mail. A detection step of detecting whether or not the mail is acceptable for delivery by checking the addresses of the original and recipients, and the title of the email, and in the detecting step, when an email that is not acceptable for delivery is detected. Includes at least a creating step for creating a warning mail indicating that an undeliverable mail is received, and a delivering step for delivering the warning mail created in the creating step to the destination of the mail. A mail server program characterized by the above. 10. From the destination to whom the warning mail is delivered,
10. The mail server program according to claim 7, further comprising a mail delivery step of delivering the mail to the destination when the mail delivery request is received. 11. When an email that is not allowed to be delivered is detected, the alert email is replaced with a delivery step of delivering the email to the destination of the email, and the alert email and the email indicating that the email is not allowed to be delivered. Together with the email,
10. The mail server program according to claim 7, further comprising a mail delivery step of delivering to the destination of the mail. 12. When delivering, it is detected whether or not the current time zone is a time zone in which the delivery is permitted, and when it is detected as a time zone in which the delivery is not permitted, the time zone in which the delivery is permitted is reached. 12. The mail server program according to claim 7, further comprising a step of waiting until and delivering.