JP4582129B2 - Mail distribution system, mail distribution method, and mail distribution program - Google Patents

Description

  The present invention relates to a mail transmission system, and more particularly to a mail transmission system that distributes electronic mail to a mobile terminal.

  The use of e-mails sent from companies to consumers includes the distribution of advertising mails such as recommended product information and event guides. In particular, the method of distributing information directly to mobile phone terminals that are likely to be always carried by consumers can directly convey information that the company wants to convey to consumers. In particular, demand is increasing.

  However, when delivering a large amount of mail (for example, 100,000 mails / hour or more) to an unspecified number of people, the receiving mail server may limit the error rate in consideration of the convenience of consumers. .

  Normally, mail is sent from the delivery instruction device to the mail delivery server, sent to the mail server corresponding to the domain name of the destination mail address, and the mail server sends the mail to the mailbox for each personal address of the destination mail address. And a mail receiving device such as a mobile phone terminal connects to the mailbox and receives the mail.

  If the mail server does not have a mailbox corresponding to the personal address of the destination mail address of the mail destination, an error may occur at the time of SMTP (Simple Mail Transfer Protocol) connection with the mail transmission server. , Send an error mail with an error message to the sender email address. For example, bounce mail / bounced mail (bounce mail / bounded mail) is known.

  Here, there are cases where the mail server measures the error rate, which is the number of errors per unit time, for each mail delivery server of the sender, and if the error rate exceeds a predetermined value, the mail delivery server Refuse to receive mail. For example, the SMTP connection with the sender mail delivery server is rejected, an error mail is returned, or the received mail is stored in a junk mail mailbox.

  Specifically, when the error rate per unit time from the same domain is high, the mail transmission for the mobile terminal is determined as an unintended random spam mail and is rejected from the destination mail server.

  For this reason, a technique for deleting the mail address of the error mail from the destination list in order to reduce the error mail from the next time is known.

For example, Japanese Patent Laid-Open No. 2000-259514 (Patent Document 1) discloses an “electronic mail destination management system”.
In this known technique, an e-mail is sent from a first computer (mail server) holding a destination list (address book / mailing list) registered e-mail addresses to a second computer (mail client) based on the destination list. In the distribution system, the mail address that could not be distributed when an error message indicating inability to distribute is received by the first computer is deleted from the destination list.

JP 2000-259514 A

  However, email addresses that wish to be delivered are added every day, including mistakes in the address entry, and the email address is stopped using every day. There may be cases where the error rate limit such as the limit is violated.

  The mail delivery server according to the present invention measures the number of mail transmission errors during SMTP connection for each mail server name and the number of errors sent by error mail in mass mail delivery, and the error rate is determined in advance. When the value (threshold) is exceeded, the IP address used to send mail addressed to the mail server that exceeds the specified value is changed, and the mail address to the mail server is sent using the changed IP address. Resume.

  In the following, means for solving the problem will be described using the numbers used in [Best Mode for Carrying Out the Invention] in parentheses. These numbers are added to clarify the correspondence between the description of [Claims] and [Best Mode for Carrying Out the Invention]. However, these numbers should not be used to interpret the technical scope of the invention described in [Claims].

  The mail delivery system of the present invention includes a mail generation unit (13) that generates a mail, receives a predetermined number of mails, transmits the mails to the mail server (30), and notifies an error notification from the mail server (30). A transmission / reception unit (22) that measures the number of errors based on the error rate, an error rate is calculated from the number of errors per predetermined number of emails, and an error determination unit (26) that determines whether the error rate exceeds a specified value; When the specified value is exceeded, an IP address list indicating IP addresses that are candidates for switching is referred to, and an address switching unit that switches the IP address used for communication with the mail server (30) to another IP address ( 27).

  When the transmission / reception unit (22) receives an error notification, the mail delivery system of the present invention further includes an error database (252) that describes the number of errors in association with the identification information of the mail server (30).

  The mail delivery system of the present invention further includes a connection table (251) in which intervals for sending mail to the mail server (30) are described. The transmission / reception unit (22) may extend the interval described in the connection table (251) when the error rate exceeds a specified value.

  The transmission / reception unit (22) may limit the number of emails received from the email generation unit (13) when the error rate exceeds a specified value.

  When the error rate exceeds a specified value, the transmission / reception unit (22) may wait for a predetermined time before transmitting the next predetermined number of mails to the mail server (30).

  It is also possible to construct a network access system by applying the mail delivery system of the present invention. The network access system of the present invention includes a transmission / reception unit (22) that accesses the server (30), and an error determination unit (26) that measures the number of accesses to the server (30) and determines whether the number of accesses exceeds a specified value. And an address switching unit (27) for switching an IP address used for communication with the server (30) when the number of accesses exceeds a specified value.

  It is possible to provide a means for delivering mail to as many mobile phone terminals as possible while observing restrictions on sending mail to mobile phone terminals.

A first embodiment of the present invention will be described below with reference to the accompanying drawings.
As shown in FIG. 1, the mail distribution system according to the present invention includes a distribution instruction device 10, a mail distribution server 20, a mail server 30, and a mail reception device 40. There may be a plurality of these devices. The number of each device is arbitrary. Each device is connected via a network. However, actually, the distribution instruction device 10 may be integrated with the mail distribution server 20. The mail delivery server 20, the mail server 30, and the mail receiving device 40 are often connected via the Internet. The mail server 30 and the mail receiving device 40 may be connected via a public telephone network.

  The distribution instruction apparatus 10 is an information processing apparatus that instructs mail distribution. Here, a PC (personal computer) is taken as an example. The mail distribution server 20 is an apparatus that receives mail and mail distribution instructions from the distribution instruction apparatus 10 and distributes them on a network under predetermined conditions. The mail server 30 receives and accumulates mail distributed from the mail distribution server 20 via the network, and provides it to the mail receiving device 40 in response to a request from the mail receiving device 40. The mail receiving device 40 is an information processing device that receives mail from the mail server 30. Here, a mobile phone is taken as an example.

The configuration of each device will be described in detail with reference to FIG.
The distribution instruction device 10 includes a network connection unit 11, a storage unit 12, a mail generation unit 13, and a transmission unit 14.

  The network connection unit 11 is connected to a network. For example, a communication interface such as NIC (Network Interface Card) is shown. The storage unit 12 stores a large number of mail addresses and mail contents. A mail address table in which a large number of mail addresses are registered may be stored. The mail generation unit 13 sequentially reads out the mail address for each domain of the mail address, and similarly generates a mail by adding the mail address to the mail content read from the storage unit 12. At this time, the mail generation unit 13 generates the generated mails (for example, 100,000 mails) so as to be transmitted to the mail distribution server 20 every predetermined number (for example, 100 mails). Here, the predetermined number of generated mails is referred to as a mail bundle for convenience. In other words, the mail bundle indicates an aggregate of a predetermined number of mails. When the last bundle is less than a predetermined number due to the fraction, this last bundle is ignored or this last bundle is exceptionally determined as one bundle. Here, the predetermined number is preferably a number that does not exceed the number of mails transmitted by each mail server 30 in one connection. This predetermined number is set in advance. Alternatively, the mail generation unit 13 receives a notification from the mail distribution server 20 regarding the number of mails that each mail server 30 transmits in one connection, and the mail generation unit 13 determines a predetermined number according to the notified number. You may make it bundle for every predetermined number. The transmission unit 14 transmits a bundle of mails to the mail distribution server 20 via the network connection unit 11. When there are a plurality of mail distribution servers 20, a bundle of mails is distributed to each mail distribution server 20. Each mail delivery server 20 distributes a bundle of different mails so that the delivered mails do not overlap. Here, one mail of a bundle of mails is transmitted to one mail distribution server 20 until a predetermined number (one bundle) is reached. Note that one bundle of emails is compressed into one file and sent to the mail delivery server 20, and the compressed file received on the mail delivery server 20 side is decompressed, so that one bundle of emails is sent to the mail delivery server 20. It is also possible to pass.

  The mail delivery server 20 includes a network connection unit 21, a transmission / reception unit 22, a timer unit 23, a temporary storage unit 24, a storage unit 25, an error determination unit 26, and an address switching unit 27.

  The network connection unit 21 connects to a network. For example, a communication interface including NIC is shown. The transmission / reception unit 22 transmits / receives mail via the network connection unit 21. In addition, an error notification indicating a mail transmission failure is received. The timer unit 23 measures time. The temporary storage unit 24 temporarily stores received mails and error mails. The storage unit 25 includes a connection table 251 and an error database 252. The connection table 251 describes the interval for transmitting mail for each mail server 30 and the number of mails to be transmitted in one connection (for example, 100). The transmission / reception unit 22 may notify the distribution instruction apparatus 10 of the number of emails transmitted in one connection. When the transmission / reception unit 22 receives an error notification from the mail server 30, the error database 252 describes the number of errors for each mail server name. The mail server name may be identification information such as a domain name or an IP address that can uniquely identify the mail server 30. The error determination unit 26 compares the error rate calculated from the number of errors in the error database 252 with a specified value (threshold value) stored in the storage unit 25 in advance, and determines whether the error rate exceeds the specified value. The error determination unit 26 may be mounted on the distribution instruction device 10. The address switching unit 27 switches the Internet side IP address (source IP address) used for communication with the mail server 30. Note that the IP address used for communication with the distribution instruction apparatus 10 is not switched. An IP address list (such as an IP address list) indicating information on IP addresses that are candidates for switching is stored in the storage unit 25. In the IP address list, a plurality of IP addresses including the IP address currently in use are described. Alternatively, the address switching unit 27 itself may have.

  The mail server 30 includes a network connection unit 31, a reception unit 32, and a storage unit 33.

  The network connection unit 31 is connected to the network. For example, a communication interface including NIC is shown. The receiving unit 32 receives mail via the network connection unit 31. The storage unit 33 includes a correspondence table 331 and a mail box 332. The correspondence table 331 describes the mail address and the mailbox identifier in association with each other. Mailbox 332 stores mail for each mailbox identifier. There may be a plurality of mailboxes 332.

  The mail receiving device 40 includes a network connection unit 41, a storage unit 42, and a mail receiving unit 43.

  The network connection unit 41 is connected to the network. For example, a communication interface including NIC is shown. The storage unit 42 stores the received mail. The mail receiving unit 43 connects to the mail server 30 via the network connection unit 41, receives mail from the mail box 332 corresponding to the personal address of the storage unit 33 of the mail server 30, and stores it in the storage unit 42.

The operation in the present invention will be described with reference to FIG.
(1) Step S101
The mail generation unit 13 of the distribution instruction apparatus 10 reads the mail address and the mail content from the storage unit 12, adds the mail address to the mail content, and creates a mail. At this time, the storage unit 12 storing the mail address and the mail content may be a storage unit of another device such as the storage unit 25 of the mail distribution server 20 connected via the network.
(2) Step S102
The transmission unit 14 of the distribution instruction apparatus 10 transmits the generated mail to the mail distribution server 20. When the storage unit 12 storing the mail address and the mail content is the storage unit 25 of the mail distribution server 20, the mail is stored in the temporary storage unit 24 of the mail distribution server 20. “Send to distribution server 20” is “instruct mail distribution server 20 to distribute the generated mail”. In addition, when the transmission part 14 of the delivery instruction | indication apparatus 10 transmits the produced | generated mail to the mail delivery server 20, it is made to transmit a bundle of mail. The number of mails included in one bundle is determined by the mail generation unit 13 of the distribution instruction device 10. That is, the mail generation unit 13 creates a mail bundle, and the transmission unit 14 transmits the mail bundle to the mail distribution server 20.
(3) Step S103
When the transmission / reception unit 22 of the mail distribution server 20 receives a mail from the distribution instruction device 10, the transmission / reception unit 22 stores the received mail in the temporary storage unit 24.
(4) Step S104
The transmission / reception unit 22 of the mail distribution server 20 transmits a mail to be transmitted per connection delivered from the distribution instruction apparatus 10 to the destination mail server 30. At this time, an SMTP session is established in the destination mail server 30, and mail transmission is performed until mail per connection is completed.
(5) Step S105
When the transmission / reception unit 22 of the mail distribution server 20 receives an error notification from the mail server 30 when an error occurs, the transmission / reception unit 22 counts (measures) the number of errors and stores the number of errors in the error database 252. At this time, the transmission / reception unit 22 is determined every predetermined unit time (for example, between 10:00 AM and 10:59 AM), every unit of mail transmission number (for example, 100), every SMTP connection, or the like. An error for each measurement unit such as every unit time is written in the error database 252 and the number of errors is counted. The error here indicates absence of a destination. That is, the mail address is wrong or the mail address is invalid. In this case, a mail transmission failure notification is received from the mail server 30. If the determination is possible, the error may include a delivery destination refusal or a communication path abnormality.
(6) Step S106
The transmission / reception unit 22 disconnects the SMTP connection when the transmission of all the mails of a bundle of mails per connection received from the distribution instruction apparatus 10 to the mail server 30 is completed.
(7) Step S107
The error determination unit 26 calculates an error rate from the number of errors per measurement unit described in the error database 252 after the connection is disconnected. The error rate is calculated according to the number of errors per unit time, the number of errors in the SMTP connection, the ratio with the number of mail transmissions, and the like. For example, the error rate is calculated on the basis of the number of emails in error in one bundle of emails.
(8) Step S108
The error determination unit 26 compares the specified value stored in advance in the storage unit 25 with the error rate, and determines whether the error rate exceeds the specified value.
(9) Step S109
When the error rate exceeds the specified value, the address switching unit 27 reads an IP address list indicating IP addresses that are candidates for switching from the storage unit 25 before sending mail for the next connection. In the IP address list, a plurality of IP addresses including the IP address currently in use are described. Here, based on the IP address list, the IP address is switched to another IP address described next to the source IP address used so far. The rules for selecting an IP address may be set freely. For example, a column for setting the priority order of IP addresses may be provided in the IP address list, and the IP address may be switched according to this priority order.
(10) Step S110
The transmission / reception unit 22 of the mail distribution server 20 receives the next mail bundle from the distribution instruction apparatus 10, establishes an SMTP session with the mail server 30, and starts mail transmission for the next connection.

  The above processing is continued until the plurality of mail distribution servers 20 independently perform the distribution instruction from the distribution instruction apparatus.

A specific example of the present invention will be described in detail with reference to FIG.
The delivery instruction device 10 sends the created emails to the email delivery server 20 as a bundle. The e-mail address indicates a registrant who wants to deliver e-mail. At this time, the distribution instruction device transmits a mail address list in which a predetermined number (for example, 100) of mail addresses are described and data regarding the contents of the mail to the mail distribution server 20, and the mail distribution server 20 An email may be created based on the content of the email. Here, the distribution instruction apparatus 10 bundles the created mails every 100 mails and transmits them to each of a plurality of mail distribution servers 20 (20-i, i = 1 to n: n is arbitrary). However, in practice, only one mail distribution server 20 may be used. Each mail delivery server 20 delivers mail to the registrant indicated by the mail address.

  Each mail delivery server 20 measures an error rate for each destination mail server 30. The destination mail server 30 is owned or managed by a telecommunications carrier (carrier) or the like. In order to transmit mail to the plurality of mail servers 30, each mail distribution server 20 has a network connection unit 21 that is a communication interface. Note that there may be a plurality of network connection units 21 in one mail delivery server 20. The network connection unit 21 has an IP address and has a one-to-one correspondence with the destination mail server 30. Each mail distribution server 20 performs distribution of bundles (in this case, 100) instructed to be distributed, and measures an error rate. If the error rate exceeds the threshold, the IP address used for communication with the mail server 30 is switched, and the next bundle (the next 100 messages) is sent to the mail server 30 using the new IP address. ).

  When a provider or the like manages the distribution instruction device 10 and the mail distribution server 20, a mail is once transmitted from the customer (user) terminal to the distribution instruction device 10, and the distribution instruction device 10 sends an e-mail for each customer. You may make it transmit to the mail delivery server 20 in a bundle. At this time, the bundle of emails includes only emails created by the same customer. The mail address list used is preferably different for each customer. However, actually, a plurality of customers can use the same mail address list.

  In mail delivery of a plurality of customers, when the mail delivery server 20 sends mail to the same mail server 30, if the error rate exceeds a specified value during mail delivery of a certain customer, the same mail address list is used. For the mail delivery of existing customers, it is determined that the error rate has exceeded the specified value. That is, first, if the error rate exceeds a specified value during delivery of a bundle of mails of one customer (100 mails here), the IP address is switched before the next delivery, and the same IP address is used. Other customers who have sent mail to the mail server 30 will also deliver the next bundle (next 100) to the mail server 30 using the new IP address.

  In the above embodiment, it is determined whether to switch the IP address based on the error rate. However, in practice, the IP address may be switched every time a predetermined number of mails are transmitted. For example, it is possible to switch the IP address each time each mail distribution server 20 transmits a bundle (for example, 100 mails) of mail.

Next, a second embodiment of the present invention will be described.
In this embodiment, when it is determined that the error rate exceeds the specified value, the transmission speed of mail addressed to the mail server exceeding the specified value is reduced. That is, the mail transmission interval is delayed. This is thought to be effective in reducing the load on the mail server due to the concentration of a large amount of mail in a short period of time. At this time, a plurality of prescribed values may be set. Here, the first specified value and the second specified value are set. The IP address is switched when the error rate exceeds the first specified value, and the mail transmission interval is delayed when the error rate exceeds the second specified value. The description of the same parts as in the first embodiment will be omitted.

With reference to FIG. 5, the operation in the present embodiment will be described.
(1) Step S201
When the transmission / reception unit 22 of the mail delivery server 20 obtains an error, it counts the number of errors and stores the number of errors in the error database 252. At this time, the transmission / reception unit 22 counts the number of errors for each predetermined measurement unit, and writes it in the error database 252. The measurement unit is the same as in the first embodiment.
(2) Step S202
When the number of mail transmissions reaches the number of transmissions in one connection of the connection table 251 stored in the storage unit 25, the error determination unit 26 disconnects the SMTP connection.
(3) Step S203
The error determination unit 26 reads the number of errors from the error database 252 and calculates an error rate. The error rate is calculated according to the number of errors per unit of measurement, such as the number of errors per unit time, the number of errors in the SMTP connection, and the ratio to the number of mail transmissions.
(4) Step S204
The error determination unit 26 compares the specified value stored in advance in the storage unit 25 with the error rate, and determines whether the error rate exceeds the first specified value.
(5) Step S205
When the error rate exceeds the first specified value, the address switching unit 27 switches the source IP address used so far to another IP address after completion of mail transmission per connection.
(6) Step S206
Further, the error determination unit 26 compares the specified value stored in advance in the storage unit 25 with the error rate, and determines whether the error rate exceeds the second specified value.
(7) Step S207
When the error rate exceeds the second specified value, the transmission / reception unit 22 reduces the mail delivery speed to the mail server 30. Here, in order to reduce the delivery speed, the value of the interval for sending mail to the mail server 30 described in the connection table 251 is increased for a predetermined time. When the transmission / reception unit transmits mail to the mail server 30, the transmission / reception unit refers to the value of the mail transmission interval to the mail server 30 described in the connection table 251 and controls the transmission interval between the mail and the mail. If the value increases, the mail delivery speed will slow down. Alternatively, the value of the number of mails transmitted in one connection described in the connection table 251 is decreased, notified to the mail generation unit 13, and the value of a predetermined number of mails transmitted to the mail distribution server 20 is changed. If the number of emails sent in one connection is reduced, the delivery speed of emails will be slow. Alternatively, after the mail transmission of the previous bundle of mails per connection before the next predetermined number of mails received from the mail generation unit 13 is transmitted to the mail server 30, the timer unit 23 measures the elapsed time, It is determined whether or not a predetermined time has elapsed, and waiting for transmission of mail for a predetermined time. The transmission speed of the mail is slowed by having a transmission interval for each bundle of mails.
(8) Step S208
The transmission / reception unit 22 of the mail distribution server 20 starts mail transmission per next connection.

  Note that if the second specified value is made smaller than the first specified value, switching of the IP address can be prevented. Further, if the second specified value is made larger than the first specified value, it is possible to prevent the IP address after switching from being switched further, and all the finite number of IP addresses in the address list are used. Can be prevented.

Next, a third embodiment of the present invention will be described.
In this embodiment, when a plurality of mails are distributed to the same mail address, the mails are transmitted from different mail servers for each mail content and type. When sending emails to the same email address, if the email address is not used, all emails sent to that email address will result in an error, and the error rate may soon exceed the specified value There is also. Therefore, the distribution instruction apparatus 10 does not include mails for the same mail address in one bundle of mails transmitted to each mail distribution server 20. For example, when different mails are distributed at the same time based on the same mail address list, one bundle of mails transmitted to each mail distribution server 20 is not included in the mail for the same mail address.

Next, a fourth embodiment of the present invention will be described.
In the present embodiment, when there are a plurality of mail distribution servers 20, the mail distribution servers 20 cooperate with each other. Each mail delivery server 20 transmits mail independently. However, if the domain name of the mail address is the same, it may be considered that different mail delivery servers 20 send mail to the same mail server 30. It is done. In this case, the distribution instruction device 10 stores the identification information of each mail distribution server 20 in association with the mail address of the mail distributed by each mail distribution server 20 or its domain name. Each mail delivery server 20 notifies the delivery instruction apparatus 10 when the error rate exceeds a specified value in mail delivery using a mail server 30 and the IP address is switched. Then, the distribution instruction apparatus 10 instructs other mail distribution servers 20 using the mail server 30 to switch the IP address used for communication with the mail server 30. The other mail distribution server 20 switches the IP address used for communication with the mail server 30 in accordance with an instruction from the distribution instruction device 10.

Next, a fifth embodiment of the present invention will be described.
In this embodiment, when countless data is downloaded from a specific server, the download requests are bundled as in the case of mail delivery in the above embodiment. In this case, the location information (such as URL) of the file to be downloaded corresponds to the mail address, and the download request corresponds to the mail. A server having a file to be downloaded corresponds to the mail server 30. For example, on the Internet, there are Web sites that provide a large amount of image data, public databases that release various data, and the like. When a large amount of desired information is acquired from such a site, it may be automatically acquired by a program or the like. However, depending on the program, the access will be repeated several times, and a heavy load will be applied to the other server, so there is a possibility that the access will be restricted from the other server. For this reason, for example, the distribution instruction apparatus 10 sends a download request to each mail distribution server 20 as a bundle for every 100 cases, and each mail distribution server 20 transmits a download request for one bundle (100 cases). Every time the IP address used for communication with the server is switched to another IP address. That is, when all the download requests for one bundle (100) are transmitted, it is considered that the error rate exceeds the specified value. In this case, the error rate is the number of actual transmissions out of one bundle (100) of download requests. The specified value is one bundle (100 cases). Here, the transmission / reception unit 22 transmits an access signal to the server. The error determination unit 26 measures the number of accesses to the server and determines whether the number of accesses exceeds a specified value. When the number of accesses exceeds a specified value, the address switching unit 27 switches the IP address used for communication with the server. Of course, in one bundle (100 cases), an error signal in response to the access signal is received from the server, an error rate is calculated based on this error signal, and if this error rate exceeds a specified value, an IP address is assigned. You may make it switch.

  In practice, it is also possible to implement a combination of the above embodiments.

  As described above, the mail delivery server of the present invention measures the number of mail transmission errors and the number of errors sent error mails during SMTP connection for each mail server name in mass mail delivery, and the error rate is determined in advance. When the specified value is exceeded, the IP address used for communication with the mail server exceeding the specified value is switched to another IP address, and the mail transmission to the mail server is resumed. In addition, the mail is delivered by adjusting the delivery speed so as not to exceed the estimated delivery speed limit of the destination mail server.

  The present invention can be used when data is distributed to an unspecified number of target persons or addresses other than mail. For example, the present invention can be applied when update data is distributed to a user of an application such as an i-appli (registered trademark). It can also be used when large-capacity data is divided and transmitted. In this case, an error response signal or the like is used as the error notification.

  In addition, the present invention is combined with a technique such as JP 2000-259514 A (Patent Document 1) that deletes an e-mail address that could not be distributed when an error message is received from a destination list. Can be reduced, and more effective mail delivery can be realized.

FIG. 1 is a diagram showing an outline of a mail delivery system of the present invention. FIG. 2 is a block diagram showing the configuration of the mail delivery system of the present invention. FIG. 3 is a flowchart showing the operation of the first embodiment. FIG. 4 is a diagram illustrating an example of mail delivery. FIG. 5 is a flowchart showing the operation of the second embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Distribution instruction apparatus 11 ... Network connection part 12 ... Memory | storage part 13 ... Mail production | generation part 14 ... Transmission part 20 ... Mail delivery server 21 ... Network connection part 22 ... Transmission / reception part 23 ... Timer part 24 ... Temporary storage part 25 ... Storage part 26 ... Error determination unit 27 ... Address switching unit 30 ... Mail server 31 ... Network connection unit 32 ... Reception unit 33 ... Storage unit 40 ... Mail reception device 41 ... Network connection unit 42 ... Storage unit 43 ... Mail reception unit

Claims (11)

An email generator for generating emails;
A transmission / reception unit that receives the mail every predetermined number, transmits the mail to a mail server, and measures the number of errors based on an error notification from the mail server;
An error rate is calculated from the number of errors per the predetermined number of the mail, and an error determination unit that determines whether the error rate exceeds a specified value;
When the error rate exceeds a specified value, an IP address list indicating IP addresses that are candidates for switching is referred to, and the IP address used for communication with the mail server is switched to another IP address. A mail delivery system. The mail delivery system according to claim 1,
When the transmission / reception unit receives the error notification, the mail delivery system further includes an error database describing the number of errors in association with identification information of the mail server. The mail delivery system according to claim 1 or 2,
A connection table in which intervals for sending mail to the mail server are described;
The transmission / reception unit extends the interval described in the connection table when the error rate exceeds a specified value. The mail delivery system according to any one of claims 1 to 3,
The transmission / reception unit restricts the number of emails received from the email generation unit when the error rate exceeds a specified value. The mail delivery system according to any one of claims 1 to 4,
The transmission / reception unit waits for a predetermined time before transmitting the next predetermined number of mails to the mail server when the error rate exceeds a predetermined value. Generating an email; and
Receiving the mail every predetermined number, sending the mail to a mail server, and measuring the number of errors based on an error notification from the mail server;
Calculating an error rate from the number of errors per the predetermined number of the mail, and determining whether the error rate exceeds a specified value;
A step of switching an IP address used for communication with the mail server to another IP address by referring to an IP address list indicating IP addresses that are candidates for switching when the error rate exceeds a specified value; An email delivery method comprising: The mail delivery method according to claim 6 , wherein
The mail delivery method further comprising the step of describing the number of errors in association with identification information of the mail server when receiving the error notification. The mail delivery method according to claim 6 or 7 ,
Describing in the connection table the interval at which mail is sent to the mail server;
E mail delivery method further comprising the step of extending the interval described in the connection table when the error rate exceeds a specified value. The mail delivery method according to any one of claims 6 to 8 ,
The mail delivery method further comprising the step of limiting the number of mails received when the error rate exceeds a specified value. The mail delivery method according to any one of claims 6 to 9 ,
The mail delivery method further comprising the step of waiting for a predetermined time before transmitting the next predetermined number of mails to the mail server when the error rate exceeds a predetermined value. A mail delivery program for causing a computer to execute the mail delivery method according to any one of claims 6 to 10 .

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