JP5597466B2 - Program, mail server - Google Patents

Description

  The present invention relates to a program.

  2. Description of the Related Art Conventionally, there is a mail server that receives and delivers electronic mail on a network through SMTP (Simple Mail Transfer Protocol).

  When a conventional mail server receives an electronic mail transmitted from a terminal or another mail server, the conventional mail server performs a process of delivering the electronic mail in the order of reception. Therefore, if an e-mail with a large mail size and an e-mail with a small mail size are received in this order, the e-mail with a small mail size is waiting for delivery during delivery of the large mail size, resulting in a delivery delay. .

  For example, in Patent Document 1 as an example of a conventional mail server, a process of transferring an e-mail to a transfer destination address in order to prevent a part of the e-mail data having a large mail size from being lost on the receiving side. There is something to do (see paragraphs 0009 and 0010 of Patent Document 1).

JP 2006-261991 A

  Usually, the sender or recipient who created the email expects the email to be immediately transmitted to the recipient. However, as described above, even if the email is small, there is a delay in delivery. May occur, and in such a case, the expectation of the sender or recipient cannot be met.

  Moreover, in the mail server as shown in Patent Document 1, the mail server of the delivery destination is made different depending on whether or not the received electronic mail exceeds the maximum size, but the electronic mail is transferred to the mail server. In the meantime, small emails will be waiting for delivery. In other words, the mail server described in Patent Document 1 also delays the delivery of electronic mail against the sender's expectation.

  The present invention has been made in view of the above-described problems, and provides a mail server program capable of delivering e-mails in an appropriate order based on the size of e-mails in a mail server that delivers e-mails. It is in.

  (1) The present invention is a program for a mail server that delivers an e-mail, and includes a receiving unit that performs a process of receiving an e-mail, and a priority of the e-mail based on the size of the e-mail. A priority determination unit that performs processing to determine, a spool control unit that performs processing to store the electronic mail in a spool area in association with the priority of the electronic mail, and is stored in the spool area based on the priority. The present invention relates to a program that causes a computer to function as a delivery unit that determines a delivery order of e-mails and performs a process of delivering e-mails according to the decided delivery order.

  The present invention also relates to an information storage medium storing the program and a mail server configured as each unit. According to the present invention, electronic mail can be delivered in an appropriate order based on the size of the electronic mail.

  (2) In the program of the present invention, the priority determination unit performs a process of determining that the priority of the e-mail is lower as the size of the e-mail is larger. You may make it perform the process which gives priority and delivers a high electronic mail. According to the present invention, electronic mail with a small size can be preferentially delivered.

  (3) In the program of the present invention, the delivery unit performs a process of re-delivery on the electronic mail determined to be a delivery error, and the priority determination unit determines the priority of the electronic mail determined to be a delivery error. The degree may be changed from the priority of the initial delivery of the e-mail to a different value. According to the present invention, since the priority of the e-mail determined to be a delivery error is changed from the priority of the initial delivery of the e-mail to a different value, the e-mail is delivered in an appropriate order for the re-delivery e-mail. can do.

An example of the network diagram of this embodiment. An example of a functional block diagram of the mail server of this embodiment. Explanatory drawing of the delivery process of the email stored in the spool area. Explanatory drawing of the delivery process of the email stored in the spool area. The flowchart figure of the process which determines the priority of this embodiment. Explanatory drawing of a spool directory. The flowchart figure of the delivery process of the email of this embodiment. The figure for demonstrating the delivery process of the email of this embodiment.

  Hereinafter, this embodiment will be described. In addition, this embodiment demonstrated below does not unduly limit the content of this invention described in the claim. In addition, all the configurations described in the present embodiment are not necessarily essential configuration requirements of the present invention.

1. Network FIG. 1 is an example of a network diagram of the present embodiment. The mail server 10 according to the present embodiment is an MTA (Mail Transfer Agent) that receives and delivers electronic mail on a network through SMTP (Simple Mail Transfer Protocol).

  The mail server 10 receives an email including an envelope destination (destination email address), an envelope sender (sender email address), and a message used for delivery processing, and receives the email received via the network. Based on the envelope destination, processing is performed for delivery to a delivery destination mail server (transmission destination mail server).

  More specifically, the mail server 10 receives an electronic mail transmitted from a MUA (Mail User Agent). Note that MUA is a client program used to send and receive e-mails at terminals on the Internet. Next, the mail server 10 sends a DNS (Domain Name System) server that manages the domain of the destination of the envelope of the received email, a DNS server in the local area of the mail server 10, or another DNS server, Queries the destination domain of the envelope of the received email (for example, queries MX records of the destination domain). Then, the electronic mail is delivered (delivered, transmitted, transferred, relayed) to the delivery destination mail server determined by the response message of the DNS server.

  Note that the mail server 10 according to the present embodiment receives an email includes a case where an email is received from a terminal via SMTP and a case where an email delivered from another mail server is received via SMTP.

  Also, the mail server 10 of the present embodiment delivers an e-mail to a process of delivering a received e-mail to another mail server via SMTP, or to a user who has an account in the same system where the mail server 10 operates. Processing for delivering to a local delivery agent MDA (Mail Delivery Agent) for delivery to the user, and processing for delivering locally to a user who has an account in the same system where the mail server operates without going through MDA.

2. Configuration FIG. 2 is an example of a functional block diagram of the mail server 10 of the present embodiment. Note that the mail server 10 according to the present embodiment does not need to include all the units illustrated in FIG.

  The storage unit 170 serves as a work area for the processing unit 100 and the like, and its function can be realized by hardware such as RAM (VRAM).

  The storage unit 170 of this embodiment includes a spool area 171. The spool area 171 is a storage area for temporarily storing an e-mail received by the receiving unit 111. Note that the e-mail stored in the spool area 171 is deleted from the spool area 171 when the delivery process is completed (normal delivery end or delivery error end). In the case of a delivery error end, that is, an electronic mail that cannot be delivered to the delivery destination mail server is stored in the spool area 171 again.

  The information storage medium 180 can be read by a computer, and the information storage medium 180 stores programs, data, and the like. That is, the information storage medium 180 stores a program for causing a computer to function as each unit of the present embodiment (a program for causing a computer to execute processing of each unit). That is, the processing unit 100 can perform various processes of the present embodiment based on data read from a program (data) stored in the information storage medium 180.

  For example, the information recording medium 180 is an optical disk (CD, DVD), a magneto-optical disk (MO), a magnetic disk, a hard disk, a magnetic tape, a memory (ROM), a memory card, or the like.

  The processing unit 100 performs various processes of the present embodiment based on a program (data) stored in the storage unit 170. Note that the processing unit 100 of the present embodiment reads the program and data stored in the information storage medium 180, stores the read program and data in the storage unit 170, and performs processing based on the program and data. Also good.

  The processing unit 100 (processor) performs various processes using the main storage unit in the storage unit 170 as a work area. The functions of the processing unit 100 can be realized by hardware such as various processors (CPU, DSP, etc.) and programs.

  The processing unit 100 includes a reception unit 111, a priority determination unit 112, a scheduled delivery time determination unit 113, a spool control unit 114, and a delivery unit 115.

  The receiving unit 111 performs processing (reception processing) of receiving an e-mail that is transmitted from the sending source and has an envelope destination designated by the MUA of the terminal (computer, mobile phone, tablet computer, smartphone).

  Further, the priority determination unit 112 performs processing for determining the priority (priority value) of the received electronic mail. For example, the priority determination unit 112 performs a process of determining the priority of the email based on the size of the email. Note that the size of the e-mail is the size of the entire message constituting the e-mail. That is, the size of the e-mail is the size of the entire data including the data of the header part, the data of the body part, and the attached file data (attached file data converted from the binary code to the text code).

  The priority determination unit 112 of the present embodiment performs a process of determining to lower the priority of the email as the size of the email is larger. For example, if the size of the e-mail is S and the priority is P, P = 50 (initial value) if S <1 megabyte, P = 40 if 1 megabyte ≦ S <2 megabyte, 2 megabyte ≦ S <P = 30 for 3 megabytes, P = 20 for 3 megabytes ≦ S <4 megabytes, P = 20 for 4 megabytes ≦ S <5 megabytes, and P = 0 for 5 megabytes ≦ S To do.

  Note that the priority determination unit 112 may determine the priority of the e-mail subject to redelivery due to a delivery error to a value lower than the initial value (50). That is, the priority determination unit 112 may change the priority of the electronic mail determined to be a delivery error from the priority of the initial delivery of the electronic mail to a different value.

  Further, the scheduled delivery time determination unit 113 performs a process of determining a scheduled delivery time (scheduled delivery date and time) for delivering the received electronic mail. Further, the scheduled delivery time determination unit 113 performs a process of determining the scheduled delivery time of the e-mail that has been redelivered due to a delivery error. For example, the time after a predetermined period (for example, 10 minutes later) based on the time of delivery error is determined as the scheduled delivery time of the e-mail subject to redelivery.

  Further, the spool control unit (queue management unit) 114 performs a process of storing (storing) the received electronic mail in the spool area 171. For example, the spool control unit 114 associates the received electronic mail, the priority of the electronic mail, and the scheduled delivery time of the electronic mail, and stores the electronic mail in the spool area 171.

  Note that the spool control unit 114 performs processing for deleting the electronic mail for which delivery processing has been completed by the delivery unit 115 from the spool area 171.

  In addition, the delivery unit 115 performs processing for delivering the e-mail stored in the spool area 171. For example, the delivery unit 115 compares the scheduled delivery time with the current time (current date and time of determination), and performs processing for delivering an e-mail whose scheduled delivery time is earlier (older) than the current time. That is, the delivery unit 115 determines whether or not the scheduled delivery time is a past time from the current time, and performs processing for delivering an e-mail whose scheduled delivery time is a past time from the current time.

  In particular, the delivery unit 115 according to the present embodiment performs processing for delivering electronic mail according to priority. That is, the delivery unit 115 determines the delivery order of the emails stored in the spool area based on the priority, and performs a process of delivering the emails according to the decided delivery order.

  For example, the delivery unit 115 performs processing for preferentially delivering high-priority electronic mail. In other words, processing is performed to deliver e-mails whose descending order of priority (in descending order of priority) and whose scheduled delivery time is a past time from the current time. When there are a plurality of e-mails having the same priority, a process of delivering the e-mails according to the scheduled delivery time is performed. That is, when there are a plurality of e-mails having the same priority, the process of delivering e-mails in the time series of the scheduled delivery time (in order from the oldest scheduled delivery time) is performed. In addition, the delivery unit 115 performs a process of redelivering an electronic mail that is determined to be a delivery error.

3. FIG. 3 is a conceptual diagram for explaining a conventional mail server delivery process. As shown in FIG. 3, the conventional mail server stores e-mails in the spool area 171 and delivers the e-mails stored in the spool area 171 in the order received.

  For example, when an e-mail 33 having a size of 5 megabytes takes a long time for delivery processing, the stored small e-mails 34, 35,... Become.

  That is, since the size of the e-mail 33 is large in the conventional mail server, it takes time to deliver the e-mail 33, and as a result, a delivery delay occurs for the e-mail 34 having a small size. Similarly, for electronic mails 35, 36,... 70 received subsequent to the electronic mail 34, a delivery delay occurs in a chained manner.

4). Description of delivery processing of mail server of this embodiment (1) Outline of delivery processing The mail server 10 of this embodiment performs processing for determining the priority of email based on the size of the email. Then, based on the priority, the order of delivery of the electronic mail stored in the spool area is determined, and the electronic mail is delivered according to the determined delivery order. In this way, electronic mail can be delivered in an appropriate order, and the delivery delay of electronic mail smaller than a predetermined size (for example, 1 megabyte) can be reduced as compared with a conventional mail server.

  FIG. 4 is a conceptual diagram for explaining the delivery process of the mail server 10 of the present embodiment. As shown in FIG. 4, the mail server 10 stores an e-mail in the spool area 171. An e-mail having a size smaller than a predetermined size (for example, 1 megabyte) has priority over an e-mail having a size larger than the predetermined size. To perform delivery processing.

  For example, when the mail server 10 receives an e-mail 34 having a size of 3 kilobytes after the e-mail 33 having a size of 5 megabytes, the mail server 10 performs processing to deliver the e-mail 34 with priority over the e-mail 33. . That is, the mail server 10 performs processing for delivering the electronic mail 34 smaller than the predetermined size stored in the spool area 171 with priority over the electronic mail 33 larger than the predetermined size, regardless of the order of receiving the electronic mail.

  When there is no longer any e-mail smaller than the e-mail 33 in the spool area as at time T51 in FIG. 4, the mail server 10 performs a delivery process for the e-mail 33. Accordingly, when a large amount of e-mail exists in the spool area 171 of the mail server 10, the e-mail having a size smaller than the predetermined size is preferentially delivered (the e-mail having a predetermined size or more is deferred), and then the mail server 10. If the number of e-mails stored in the spool area 171 decreases, e-mails of a predetermined size or larger can be delivered.

  That is, since the electronic mail 33 has a large amount of communication, the sender and the receiver may be convinced that the delivery delay of the electronic mail 33 occurs. However, if the e-mails 34 and 35 having a size smaller than the predetermined size are delayed due to the e-mail 33, the sender or the recipient may feel irritation or stress due to the delivery delay.

  However, according to the present embodiment, it is possible to prevent a delay in delivery of a relatively small e-mail smaller than a predetermined size, so that both the sender and the recipient have no stress on a small e-mail smaller than the predetermined size. You can send and receive. Hereinafter, the process of the mail server 10 of this embodiment will be described in more detail.

(2) Processing for Determining Priority When receiving the electronic mail, the mail server 10 of this embodiment performs processing for determining the priority of the electronic mail before storing it in the spool area 171.

  For example, when the size S of the electronic mail is smaller than 1 megabyte (an example of a predetermined size) (S <1 megabyte), the priority of the electronic mail is determined to be an initial value (initial value = 50).

  On the other hand, when the size S of the electronic mail is 1 megabyte or more, a process of subtracting 10 in units of 1 megabyte from the priority 50 of the initial value is performed.

  In other words, in the present embodiment, the process of determining the priority is performed so that the e-mail having a predetermined size or larger becomes lower in priority as the mail size increases in units of 1 megabyte.

  Specifically, the priority P can be obtained by the following equation (1). In the following formula (1), the value when the size of the e-mail is shown in megabytes is S (the fractional part of the e-mail size S is rounded down).

P = 50− (S × 10) (1)
For example, the priority P of a 1.2 megabyte e-mail is 50− (1 × 10) = 40. In addition, the priority P of the 2.4 megabyte e-mail is 50− (2 × 10) = 30. The priority P of the 5.8 megabyte e-mail is 50− (5 × 10) = 0. That is, the priority is determined by lowering the priority of the email as the size of the email increases.

  Furthermore, the flow of priority determination processing will be specifically described with reference to FIG. First, an initial value (= 50) is substituted for priority (step S1). Next, it is determined whether or not the size of the e-mail is smaller than a predetermined size (for example, 1 megabyte) (step S2).

  Then, if the size of the e-mail is smaller than the predetermined size (yes in step S2), the process is terminated. The priority is calculated (step S3). For example, the priority is calculated by the above equation (1).

  Then, it is determined whether or not the priority is lower than 0 (priority <0) (step S4). When the priority is smaller than 0 (when the priority is negative) (Yes in step S4), 0 is substituted for the priority. That is, the priority is set to 0 so as not to become a negative value (step S5).

  If the priority is 0 or more (step S4: no), it is determined whether the priority is greater than 100 (step S6). If the priority is greater than 100 (yes in step S6), 100 is substituted for the priority (step S7). On the other hand, if the priority is 100 or less (no in step S6), the process ends. The process ends here.

(3) Scheduled Delivery Time When receiving the electronic mail, the mail server 10 of this embodiment determines the scheduled delivery time before storing it in the spool area 171. That is, each electronic mail stored in the spool area 171 is associated with the scheduled delivery time.

  For example, when the mail server 10 receives an electronic mail, the mail server 10 determines a scheduled delivery time of the electronic mail based on the reception time. For example, the mail server 10 may set a predetermined time ahead (for example, 5 seconds ahead) as the scheduled delivery time for the e-mail based on the e-mail reception time. Further, the reception time of the electronic mail may be set as the scheduled delivery time of the electronic mail.

(4) Spool Control When receiving the electronic mail, the mail server 10 according to the present embodiment performs a process of storing the received electronic mail as a spool file in a spool directory created in the spool area 171 of the storage unit 170.

  Here, the spool area is a memory area for temporarily storing received electronic mail. Usually, since the communication speed is extremely slower than the processing speed of the computer, the electronic mail delivery process is started after temporarily storing the received electronic mail in the spool area. In other words, the spool area is a queue area for temporarily storing electronic mail.

  The spool file is an electronic mail. That is, the spool file is a file in which the entire message data composed of the header part data and the body part data making up the electronic mail are combined into one. That is, when a file is attached to one electronic mail, a file in which the entire message data including the data of the attached file is combined into one is used as the spool file. When the attached file data is binary data, it is converted into text data with a predetermined character code. The message data is created based on the standard of MIME (Multipurpose Internet Mail Extensions).

  In the present embodiment, as shown in FIG. 6A, in the spool directory, the priority directory and the year, month, day, hour, minute, and second directories indicating the scheduled delivery time are created hierarchically, A process of storing the e-mail as a spool file is performed in the created “second” directory at the lowest level.

  For example, as shown in FIG. 6B, a “/ var / spool / mail /” directory is preset as a spool directory. Then, a “50 /” directory with a priority of 50 and “30 /” with a priority of 30 are created in the “/ var / spool / mail /” directory. The priority directory may be created in advance, or if the priority directory does not exist, it is created before storing the e-mail in the spool area 171.

  Then, the year, month, day, hour, minute, and second directories indicating the scheduled delivery time are created below the priority directory, and the received e-mail is stored as a spool file in the “second” directory. .

  For example, as shown in FIG. 6B, the spool file name of the electronic mail 34 is “mail 34”, the priority of the electronic mail 34 is determined to be “50”, and the scheduled delivery time of the electronic mail 34 is 2010 At 15: 01: 5 on the first day of the month, the spool file mail 34 of the e-mail 34 is stored in the “/ var / spool / mail / 50/2010/6/1/15/1/5 /” directory. For example, when there are a plurality of emails having the same “priority” and “scheduled delivery time”, they are stored in the same directory.

  The mail server 10 according to the present embodiment performs spool control on the received electronic mail in the spool area 171 using a directory indicating the priority and the scheduled delivery time. The spool control may be performed by associating (spool file), priority, and scheduled delivery time into a database.

(5) Delivery processing The mail server 10 of this embodiment repeatedly performs delivery processing for the maximum number of deliveries (for example, 100) out of spool files (e-mail) stored in the spool directory. Then, the spool file is processed in the descending order of priority, and the spool file whose delivery schedule time is earlier than the current time (judgment time) is delivered.

  More specifically, with reference to FIG. 7, first, the number of cases to be transmitted in one search is substituted for the maximum number of deliveries (step S10). For example, when a maximum of 100 items are delivered in one search, the maximum number of deliveries is 100. Also, an initial value (0) is substituted for the number of delivery processes.

  Then, the directory name “numeric value” in the spool directory is searched (step S11). For example, when the spool directory is “/ var / spool / mail /”, the directory having the name “numerical value” is searched in the “/ var / spool / mail /” directory. In other words, in the present embodiment, “priority” is represented by a numerical value, so that a search result is a search for a directory with the name “priority”.

  For example, as shown in FIG. 6B, when directories “50” and “30” exist in the “/ var / spool / mail /” directory, the directories “50” and “30” are searched. The

  Next, in order of priority (step S12), in the "year / month / day / hour / minute / second /" directory of the priority directory, "year / month / day / hour / minute / second" For the “second” directory (step S13) in which the scheduled delivery time specified by “/” is older than the current time, the delivery processing is performed for the spool file in the “second” directory. Each time the spool file delivery process is performed, the number of delivery processes is counted (step S14).

  That is, the scheduled delivery time specified by each directory name of “year / month / day / hour / minute / second /” of the priority directory in the descending order of priority directory (in descending order of priority) Repeat the delivery process for spool files older than the time. (Step S12 to Step S18). That is, if the scheduled delivery time is a date and time that is in the future of the current time, delivery processing is not performed for spool files in the “year / month / day / hour / minute / second /” directory of the scheduled delivery time.

  For example, in step S13, the time (current time, determination time) for determining whether or not the scheduled delivery time is an old directory of priority 50 is June 1, 2010, 15:00 shown in FIG. 6B. In the case of 1 minute 10 seconds, the “2010/6/1/15/1/5 /” directory in the “/ var / spool / mail / 50 /” directory and “2010/6/1/15/1” The process of delivering the spool files mail 34 and mail 35 in the / 6 / "directory is performed.

  When the delivery process is completed for a spool file with a priority 50 directory and a scheduled delivery time older than the current time, a spool file with a priority 30 and a scheduled delivery time older than the current time is delivered. To do. For example, the delivery process is performed for the spool file mail 33 in the “2010/6/1/15/1/1” directory.

  When there are a plurality of directories having the same priority and an estimated delivery time older than the current time, spool files in the directory may be delivered in random order, or a time series of scheduled delivery times ( Spool files may be delivered in the oldest order.

  Note that the mail server 10 of the present embodiment may establish a plurality of communications (sessions) with the delivery destination mail server and simultaneously deliver a plurality of spool files to the delivery destination mail server in parallel. In addition, the mail server 10 may establish communication with each of a plurality of delivery destination servers, and deliver an email to each delivery destination mail server in parallel.

  Also, an e-mail for which a session with the mail server of the delivery destination has been established and the delivery process is started will not be interrupted until the delivery process of the e-mail is completed (normal end or error end). Therefore, the e-mail for which the delivery process has been started is not delayed.

  In addition, the mail server 10 according to the present embodiment performs a process of deleting (erasing) the spool file for which the delivery process has been completed (normal end or error end) from the spool area 171. A spool file (e-mail) for which delivery processing has ended in error is determined by determining the scheduled delivery time and priority determined based on the error end time, creating a directory, and storing it in the created directory.

  Before deleting the spool file, the spool file may be stored in a storage area different from the spool area 171 of the storage unit 170 or in a storage area of another computer (storage server). .

  As described above, the mail server 10 according to the present embodiment performs a loop (repetition process) in steps S12 to S18 and a loop in steps S13 to S17. After the delivery process for the spool file in the “second” directory, the delivery is performed. It is determined whether or not the number of processes exceeds the maximum number of deliveries (step S15). In other words, in the present embodiment, the number of delivery processes is counted every time the delivery process is performed (step S14), and if the counted number of delivery processes exceeds the maximum number of deliveries (yes in step S15), a loop is executed. The process is interrupted and the process is terminated (step S16). On the other hand, when the number of delivery processes does not exceed the maximum number of deliveries (no in step S15), the next “second” directory delivery process is performed.

  This is the end of the process. Since the mail server 10 of this embodiment is a resident server, when the delivery process in one search is completed, the process returns to the start and the process of FIG. 7 is repeated.

  As described above, according to the present embodiment, an email whose mail size is smaller than a predetermined size (for example, 1 megabyte) is preferentially delivered, and an email larger than the predetermined size is delivered later. Smaller emails can be prevented from causing delivery delays.

  In addition, when delivery processing is performed for an e-mail having a predetermined size or more, the number of e-mails (the number of spool files) stored in the spool area 171 is reduced. It is possible to minimize a delivery delay of an e-mail having a size less than a predetermined size.

  That is, according to the mail server 10 of the present embodiment, as shown in FIG. 8, when the e-mails with the priorities 50, 40, and 30 are stored in the spool area 171 from T100 to T103, the Nth search In both the (N + 1) th search and the (N + 2) th search, first, delivery of an e-mail with a priority of 50 is preferentially performed.

  For example, in the N-th and N + 1-th searches, it can be said that the number of delivery processes with priority 50 exceeds the maximum number of deliveries and delivery with priorities 40 and 30 is not possible. However, it is possible to quickly deliver an e-mail smaller than a predetermined size.

  In the (N + 2) th search, when the delivery process with the priority level 50 ends, the delivery process number does not exceed the maximum delivery number and the delivery process with the priority level 40 is started. At the time of completion, the delivery process number does not exceed the maximum delivery number, and the delivery process with the priority 30 is started. That is, in the (N + 2) th search, the number of e-mails less than a predetermined size is reduced, and delivery of e-mails larger than a predetermined size is started after delivery of e-mails less than a predetermined size. Therefore, it is possible to minimize the delivery delay of the e-mail smaller than the predetermined size caused by the delivery process of the e-mail larger than the predetermined size.

(6) Re-delivery processing When the delivery of the e-mail that has been delivered is an error, the mail server 10 according to the present embodiment re-delivery the e-mail after a predetermined period based on the time of delivery error. Therefore, in the present embodiment, the priority of the redelivery target e-mail may be lowered. That is, when the mail server 10 performs a process of redelivery of an electronic mail determined to be a delivery error, the mail server 10 determines the priority of the electronic mail determined to be a delivery error from the priority of the initial delivery of the electronic mail. You may make it change into a different value.

  For example, when the delivery processing result of the electronic mail 70 is an error, 10 is further subtracted from the priority value determined based on the mail size, and the subtracted value is determined as the final priority of the electronic mail 70. Specifically, if the priority at the first delivery of the e-mail 70 is determined to be 50 and the first delivery of the e-mail 70 is an error, the priority of the e-mail 70 is changed from 50 to 40. Then, the scheduled delivery time of the e-mail 70 is determined to be 10 minutes after the end of the error. Then, a directory is created based on the determined priority and scheduled delivery time, and the e-mail 70 is stored in the created directory.

  In this way, the first delivery e-mail (e-mail that is not re-delivery) can be preferentially delivered over the re-delivery e-mail. Usually, an e-mail to be redelivered may result in an error again. In such a case, the processing time tends to increase and the processing load tends to increase. Therefore, it is possible to prevent delay by delivering the first delivery e-mail with priority and postponing the re-delivery e-mail.

  Note that the mail server 10 of this embodiment may determine the priority based on the number of delivery errors regardless of the mail size. For example, the priority is set to 50 for the first time, the priority is set to 40 for the first error, the priority is set to 30 for the second error, and so on. It may be determined to lower the priority as the number of deliveries increases.

  In addition, the mail server 10 according to the present embodiment may determine the priority based on the mail size, and subtract a value corresponding to the number of delivery errors from the priority. For example, the priority is determined according to the flowchart of FIG. 5, and a value corresponding to the number of delivery errors is subtracted from the priority. For example, when the priority at the time of the first delivery is 30, when the first delivery error occurs, the predetermined value 10 is subtracted from the priority. That is, the priority at the time of re-delivery is 20. When a second delivery error occurs, the predetermined value 10 is further subtracted from the priority. That is, the priority at the time of re-delivery is 10. Note that when a repeated delivery error occurs, the priority may become a negative value. In such a case, the priority may be forcibly determined to be 0.

(7) About Setting Processing The mail server 10 according to the present embodiment includes a setting unit that sets a “predetermined size” that serves as a criterion for determining the size of mail based on user (administrator) input information. Also good. The setting unit may set an “initial value” of the priority based on user input information.

  In the present embodiment, an example in which the priority fluctuation range (decrease amount) is set to “10” in units of “1 megabyte” has been described. However, the setting unit of the mail server 10 according to the present embodiment receives user input. Based on the information, the “size unit” and “variation range” of the e-mail for controlling the fluctuation range of the priority may be set.

  For example, based on user input information, “predetermined size” is set to “3 megabytes”, priority “initial value” is set to “50”, “size unit” is set to “2 megabytes”, When “Variation” is set to “5”, the priority for e-mails whose size is less than 3 megabytes is determined to the initial value (50), and for e-mails whose size is 3 megabytes to less than 5 megabytes Is determined to be 45, and the priority for electronic mail having a size of 5 megabytes to less than 7 megabytes is determined to be 40.

  In the present embodiment, a “maximum number of deliveries” that is an upper limit for delivery in one search may be set based on user input information.

  In this way, the administrator can appropriately set the mail server 10 so as not to cause a delay in delivery of electronic mail.

5. Modifications (1) Delivery Processing Based on Priority In the present embodiment, delivery may be preferentially delivered as the size of the email is larger. That is, an electronic mail having a predetermined size (for example, 1 megabyte) or more may be delivered with priority over an electronic mail having a size smaller than the predetermined size. In such a case, the priority determination process is modified, or the delivery order of e-mails is changed to ascending order of priority (in order from the lowest priority).

  For example, when the priority determination process is modified, an e-mail having a predetermined size (for example, 1 megabyte) or more has a higher priority than an e-mail having a size smaller than the predetermined size. Then, the priority may be increased as the mail size increases in units of 1 megabyte, and the priority determination process may be performed.

  In this way, e-mails can be delivered in an appropriate order in an environment where there is a desire to deliver a mail having a large mail size preferentially.

  In this embodiment, the example in which the first delivery e-mail is delivered with priority over the re-delivery e-mail has been described. However, the re-delivery e-mail is delivered with priority over the first delivery e-mail. You may do it. In such a case, the priority determination process is modified, or the electronic mail delivery order is changed to ascending order of priority (in order from the lowest priority).

  For example, when the priority determination process is modified, if the result of the electronic mail delivery process is an error, the priority is determined so as to increase the priority according to the number of delivery errors. For example, as the number of delivery errors increases, the priority is increased by 10 (for example, if a delivery error occurs when the priority at the time of initial delivery is 50, the priority is increased from 50 to 60). Also good. In such a case, the priority may be determined according to the flowchart of FIG. 5 and a numerical value (for example, 10) corresponding to the number of retransmission errors may be added from the priority. If the priority is a value greater than 100, the priority may be forcibly determined to be 100.

  In this way, in the case of the mail server 10 in which the redelivery electronic mail is accumulated in the spool area 171 and the storage area is compressed, the storage area can be secured rather than the problem of delivery delay.

(2) Delivery processing based on the priority described in the mail header The mail server 10 of the present embodiment may determine the priority of the e-mail based on the priority information described in the header of the e-mail. Good. For example, when the “Subject” header includes a character string “priority 60”, the priority is determined to be 60, and a priority directory is created in the spool directory based on the determined priority, and the priority is determined. Perform delivery processing.

(3) Processing for determining priority based on specific character string The mail server 10 of the present embodiment searches for a specific character string in the header part and body part of the received electronic mail, and determines the priority based on the search result. You may make it do.

  For example, the case where the character string “emergency” is a specific character string will be described. If the character string “emergency” exists in the received e-mail (for example, the header part or body part of the e-mail), priority is given. A value obtained by adding a predetermined value (= 10) to the initial value (= 50) of the degree, that is, 60 may be determined as the priority of the e-mail. On the other hand, when there is no “emergency” character string in the header part or body part of the received electronic mail, the priority of the electronic mail is determined to be an initial value (= 50). In this way, urgent electronic mail can be delivered with higher priority.

  Further, for example, when a character string reminiscent of spam mail is preset as a specific character string and the specific character string exists in the e-mail, a predetermined value (= 40) is set as the initial priority value (= 50). ), I.e., 10 may be determined as the priority of the e-mail. In this way, delivery of electronic mail that should not be delivered can be postponed.

  Moreover, the mail server 10 of this embodiment may determine a priority based on a mail size and the search result of a specific character string. For example, the priority may be determined according to the flowchart of FIG. 5, and when a specific character string exists in the e-mail, a value corresponding to the specific character string may be added (or subtracted). When the priority is a negative value, the priority may be forcibly determined to be 0.

10 mail server, 100 processing unit, 111 receiving unit, 112 priority determining unit,
113 scheduled delivery time determination unit, 114 spool control unit, 115 delivery unit,
170 Storage unit, 171 Spool area

Claims (6)

A program for a mail server that delivers electronic mail,
A receiving unit that performs processing to receive an email;
A priority determination unit that performs processing for determining the priority of the e-mail;
A spool control unit that performs processing for storing the email in a spool area in association with the priority of the email;
Determine a delivery order of emails stored in the spool area based on the priority, and function a computer as a delivery unit that performs processing to deliver emails according to the decided delivery order;
The delivery unit is
For emails that are determined to have a delivery error, re-deliver the email,
The priority determination unit
Change the priority of the email determined to be a delivery error from the first delivery priority of the email to a lower value according to the number of delivery errors ,
The delivery unit is
A program for performing a process of preferentially delivering an e-mail having a high priority . A program for a mail server that delivers electronic mail,
A receiving unit that performs processing to receive an email;
A priority determination unit that performs processing for determining the priority of the e-mail;
A spool control unit that performs processing for storing the email in a spool area in association with the priority of the email;
Determine a delivery order of emails stored in the spool area based on the priority, and function a computer as a delivery unit that performs processing to deliver emails according to the decided delivery order;
The delivery unit is
For emails that are determined to have a delivery error, re-deliver the email,
The priority determination unit
Change the priority of the email that was determined to be a delivery error from the first delivery priority of the email to a higher value ,
The delivery unit is
A program for performing a process of preferentially delivering an e-mail having a high priority . A program for a mail server that delivers electronic mail,
A receiving unit that performs processing to receive an email;
A priority determination unit that performs processing for determining the priority of the e-mail;
A spool control unit that performs processing for storing the email in a spool area in association with the priority of the email;
Determine a delivery order of emails stored in the spool area based on the priority, and function a computer as a delivery unit that performs processing to deliver emails according to the decided delivery order;
The delivery unit is
For emails that are determined to have a delivery error, re-deliver the email,
The priority determination unit
Change the priority of the email determined to be a delivery error from the first delivery priority of the email to a higher value according to the number of delivery errors ,
The delivery unit is
A program for performing a process of preferentially delivering an e-mail having a high priority . A mail server that delivers email,
A receiving unit that performs processing to receive an email;
A priority determination unit that performs processing for determining the priority of the e-mail;
A spool control unit that performs processing for storing the email in a spool area in association with the priority of the email;
A delivery unit that determines a delivery order of emails stored in the spool area based on the priority, and performs processing to deliver emails according to the decided delivery order;
The delivery unit is
For emails that are determined to have a delivery error, re-deliver the email,
The priority determination unit
Change the priority of the email determined to be a delivery error from the first delivery priority of the email to a lower value according to the number of delivery errors,
The delivery unit is
A mail server characterized in that a process for preferentially delivering high-priority electronic mail is performed. A mail server that delivers email,
A receiving unit that performs processing to receive an email;
A priority determination unit that performs processing for determining the priority of the e-mail;
A spool control unit that performs processing for storing the email in a spool area in association with the priority of the email;
A delivery unit that determines a delivery order of emails stored in the spool area based on the priority, and performs processing to deliver emails according to the decided delivery order;
The delivery unit is
For emails that are determined to have a delivery error, re-deliver the email,
The priority determination unit
Change the priority of the email that was determined to be a delivery error from the first delivery priority of the email to a higher value,
The delivery unit is
A mail server characterized by preferentially delivering high priority emails
. A mail server that delivers email,
A receiving unit that performs processing to receive an email;
A priority determination unit that performs processing for determining the priority of the e-mail;
A spool control unit that performs processing for storing the email in a spool area in association with the priority of the email;
A delivery unit that determines a delivery order of emails stored in the spool area based on the priority, and performs processing to deliver emails according to the decided delivery order;
The delivery unit is
For emails that are determined to have a delivery error, re-deliver the email,
The priority determination unit
Change the priority of the email determined to be a delivery error from the first delivery priority of the email to a higher value according to the number of delivery errors,
The delivery unit is
A mail server characterized in that a process for preferentially delivering high-priority electronic mail is performed.

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