JP2005236845A - Electronic mail substitution apparatus and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an additional service for electronic mail completely without depending on a mail server. <P>SOLUTION: A mail server 1 offers a service of using an SMTP to receive mails sent from a user terminal 5 and another mail server 6 and to distribute the mail to the other mail server 6 or to store the mail in a mailbox 7. An electronic mail substitution apparatus 2 is installed on a pre-stage of the mail server 1, substitutively receives mail sent to the mail server 1, executes control for enabling a mail sender or a mail recipient to determine an additional service under a utilization contract and for relaying mail to additional service servers 3-1 to 3-n for providing the determined additional service, and transmits mail to which the additional service is completely applied, to the mail server 1. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electronic mail proxy device for implementing additional services such as virus checking on electronic mail on the mail server side.

  The mail server receives mail sent from the user terminal or other mail server using SMTP (Simple Mail Transfer Protocol) and distributes the received mail to the target mail server or to the mailbox. Provide a service to save. In recent years, apart from such basic services, additional services such as virus checking have been implemented on the mail server side.

  An example of a prior art that implements an additional service for electronic mail on the mail server side is described in Patent Document 1. As shown in FIG. 6, this prior art includes a mail server 101 connected to the Internet 104, a database 102 connected to the mail server 101, a mail box 103, and various server units 105.

  The various server units 105 include a virus deletion server 1051, a virus mail deletion server 1052, a content filter deletion server 1053, a content filter reply server 1054, a spam check server 1055, and other additional service servers 1056.

  The virus deletion server 1051 receives the mail sent from the mail server 101, checks whether the mail does not contain a virus, and if the virus is included as a result of this check, deletes the virus. The deleted mail is returned to the mail server 101.

  The virus mail deletion server 1052 receives the mail sent from the mail server 101 and checks whether the mail does not contain a virus. As a result of this check, the mail containing the virus is deleted. Only mail that does not contain a virus is returned to the mail server 101.

  The content filter deletion server 1053 receives the mail sent from the mail server 101, checks whether or not the character string registered in the content filter in advance is included, and as a result of this check, registers in the content filter. E-mails that include the character strings that are included are deleted, and only e-mails that do not include such character strings are returned to the mail server 101.

  The content filter reply server 1054 receives the mail sent from the mail server 101, checks whether or not a character string registered in the content filter is included in advance, and as a result of this check, registers in the content filter. The mail including the character string that is displayed is returned to the sender, and only mail that does not include such a character string is returned to the mail server 101.

  The spam check server 1055 receives the mail sent from the mail server 101 and checks whether the mail is not spam mail (Spam Mail) sent indiscriminately. As a result of the check, the spam mail is deleted. Then, only mail other than spam mail is returned to the mail server 101.

  In the database 102, additional services with which the user has subscribed are registered.

  Next, the operation of the conventional electronic mail system configured as described above will be described.

  A mail server 101 that has received a mail from a user terminal or other mail server through the Internet 104 refers to the database 102 based on the mail transmission address or reception address, and the user of the mail sender or mail receiver makes a use contract. The additional service that has been subscribed to is determined, and a header corresponding to the additional service with which the service is subscribed is added to the mail. For example, in the case of a mail addressed to a user who has contracted to use three additional services: a virus deletion function, a content filter deletion function, and a spam check function, the header corresponding to these three functions is added to the mail. In addition, a function end header is added to distinguish newly received mail from mail using the function. In addition, in the case of an email sent by a user who has contracted to use two additional services, the virus email deletion function and the content filter reply function, for the sent email, a header corresponding to these two functions and a function end header To the email.

  Next, the mail server 101 reads the header, determines the additional service to be used, transmits the mail to the servers 1051 to 1056 that provide the additional service, and deletes the corresponding header when the mail is returned from the additional service server. By repeating this process until the function end header is read, the additional service contracted by the user is executed.

  For example, when headers corresponding to three additional services of a virus deletion function, a content filter deletion function, and a spam check function are added to the received mail in that order, the mail server 101 first sends a mail to the virus deletion server 1051. When the mail is returned from the virus deletion server 1051, the header corresponding to the virus deletion function is deleted, and the mail is transmitted to the content filter deletion server 1053 according to the header corresponding to the next content filter deletion function. Similarly, when a mail is returned from the content filter deletion server 1053, the header corresponding to the content filter deletion function is deleted, and the mail is transmitted to the spam check server 1055 according to the header corresponding to the next spam check function. When a mail is returned from the check server 1055, the header corresponding to the spam check function is deleted. When the next header is recognized as a function end header, the mail is stored in the user's mail box 103.

  When the headers corresponding to the two additional services of the virus mail deletion function and the content filter reply function are added to the transmitted mail in that order, the mail server 101 first transmits the mail to the virus mail deletion server 1052. When a mail is returned from the virus mail deletion server 1052, the header corresponding to the virus mail deletion function is deleted, and the mail is transmitted to the content filter reply server 1054 according to the header corresponding to the next content filter reply function. When a mail is returned from the content filter reply server 1054, the header corresponding to the content filter reply function is deleted, the next header is recognized as a function end header, and the mail is sent to another appropriate mail server. Deliver to.

As described above, in the prior art described in Patent Document 1, the mail server 101 refers to the database 102 to determine the additional service with which the user has a usage contract, and mails the header corresponding to the additional service with which the usage contract has been made. By adding to the mail, the mail itself holds the type of additional service it receives. Then, the mail server 101 refers to each header and distributes the mail to the additional service servers 1051 to 1056 that provide the corresponding additional service, thereby providing each user with only the additional service contracted by the user. It is possible to do.
JP 2003-218944 A

  According to the prior art described in Patent Document 1 described above, it is possible to provide an additional service contracted by the user on the mail server side to the user of the mail sender or mail receiver. However, there are the following problems.

  In order to provide the supplementary service, it is necessary to significantly modify the mail server, and the supplementary service increases the load on the mail server. The reason is that the mail server itself must execute processing such as determining the additional service that the mail sender or mail receiver has subscribed to, and sending the mail to the additional service server that provides the determined additional service. This is because the mail server is deeply involved in providing additional services.

  It is necessary to add a header corresponding to the additional service to the mail. The reason is that by adding a header corresponding to the additional service to be used to the mail, the mail itself holds the type of additional service received by the mail, and the mail server provides the corresponding additional service by referring to the header. This is because mail is distributed to the additional service server. Although the header is deleted after the additional service ends, it is desirable to avoid adding a special header to the user's mail as much as possible.

  The present invention has been proposed in view of such circumstances, and an object thereof is to realize an additional service for electronic mail in a form that does not depend on a mail server at all.

  Another object of the present invention is to make it possible to provide an additional service for electronic mail without performing any processing such as adding a special header to the mail itself.

  The electronic mail proxy device of the present invention is a mail server that provides a service for receiving mail sent from a user terminal and another mail server using SMTP and distributing it to another mail server or storing it in a mailbox. Additional service server that is installed in the preceding stage, receives the mail sent to the mail server on behalf, determines the additional service subscribed to by the mail sender or mail receiver, and provides the determined additional service Control is performed to relay the mail to the mail server, and the mail for which the application of the additional service is finished is transmitted to the mail server. More specifically, the first e-mail proxy device receives mail sent to the mail server by SMTP communication at a general-purpose receiving port on behalf of the mail server, and is sent from an external additional service server. A mail receiving unit that receives incoming mail at a dedicated reception port predetermined for each additional service server, and a sender / receiver determination that determines at least one of the sender and receiver of the mail received by the mail receiving unit A customer information inquiry unit for checking the type of additional service with which the user has subscribed, a predetermined additional service application order, the type of additional service determined by the customer information inquiry unit, and the mail receiving port And whether there are additional services to be performed on the email based on the type of If there is no additional service to be executed, it is determined whether the additional service to be executed next is determined. In this case, a mail relay control unit that determines the relay destination of the mail as an additional service server that provides an additional service to be executed next, and mail transmission that transmits the mail to the relay destination determined by the mail relay control unit Department.

  Further, the second electronic mail proxy device of the present invention is the first electronic mail proxy device, wherein instead of the mail receiving unit, mail sent to the mail server by SMTP communication is used instead of the mail server. The mail distributed from the load balancer received at the general-purpose receiving port is received at the reception port, and the mail sent from the external additional service server, received by the load balancer and distributed from the load balancer is added. A mail receiving unit is provided for receiving at a dedicated receiving port predetermined for each service server.

  According to the electronic mail proxy device of the present invention, an additional service for electronic mail can be realized in a form that does not depend on the mail server at all. The reason is that the e-mail proxy device receives e-mail sent to the mail server on behalf of the e-mail, determines the additional service that the e-mail sender or e-mail recipient has subscribed to, and provides this determined additional service. This is because the control of relaying the mail to the additional service server is executed, and the mail after the application of the additional service is transmitted to the mail server. As a result, it is not necessary to significantly modify the mail server to provide the additional service, and there is no concern that the load on the mail server will increase due to the additional service during operation.

  It is possible to provide an additional service for an e-mail without performing any processing such as adding a special header to the e-mail itself. The reason is that the order of application of the additional service is determined in advance, and the port for receiving mail sent from the additional service server is a dedicated reception port corresponding to the additional service server on a one-to-one basis, and the dedicated reception port for receiving the mail This is because the type of additional service applied to the mail is determined based on the above.

  Referring to FIG. 1, an electronic mail system according to an embodiment of the present invention is provided with an electronic mail proxy device 2 in front of the mail server 1, and the electronic mail proxy device 2 includes a plurality of additional service servers 3. -1 to 3-n and the customer management system 4 are connected. Additional service servers 3-1 to 3-n are equivalent to servers such as virus deletion server 1051, virus mail deletion server 1052, content filter deletion server 1053, content filter reply server 1054, and spam check server 1055 shown in FIG. It is a server having a function. In FIG. 1, 5 is a user terminal, 6 is a mail server other than the mail server 1, 7 is a mail box of the mail server 1, and 8 is customer information including at least the type of additional service with which the user has a contract. This is a customer information database held for each customer. The electronic mail proxy device 2 and the other mail server 6 are connected through a network such as the Internet, but the network is not shown.

  The mail server 1 receives mail sent from the user terminal 5 and another mail server 6 using SMTP, distributes the received mail to another mail server 6 of interest, or stores it in the mail box 7. To provide services. The e-mail proxy device 2 installed in the front stage of the mail server 1 has a function of receiving mail sent by SMTP communication from the user terminal 5 and other mail server 6 to the mail server 1 as a proxy, and the mail. A function for identifying at least one of the sender and receiver of the user, a function for acquiring the type of additional service subscribed to by the identified user from the customer information database 8 through the customer management system 4, and a function used by the user A function of relaying mail to the additional service servers 3-1 to 3-n that provide the contracted additional service, and passing the mail that has been executed for all the additional services contracted for use to the original mail server 1; It has.

  As described above, the electronic mail system according to the present embodiment determines the additional service with which the mail sender or the mail receiver has a usage contract, and the additional service servers 3-1 to 3-n that provide the determined additional service. Since the e-mail proxy device 2 executes processes such as mail relay, it is not necessary to significantly modify the mail server 1 to provide additional services, and the load on the mail server 1 is increased by the additional services. Also disappear.

  Next, the detailed configuration and operation of the present embodiment will be described in detail with a focus on the electronic mail proxy device 2.

  Referring to FIG. 2, an example of the electronic mail proxy device 2 includes an electronic mail reception unit 21, a sender / receiver determination unit 22, a customer information inquiry unit 23, a mail relay control unit 24, and an electronic mail transmission unit 25. And a storage unit 26. Each functional unit can be realized by, for example, a computer and a program configuring the electronic mail proxy device 2. The program is recorded on a computer-readable recording medium 9 such as a magnetic disk, and is read by the computer when the computer is started up, and by controlling the operation of the computer, the e-mail receiving unit 21 transmits and receives on the computer. Each function part of the person discrimination | determination part 22, the customer information inquiry part 23, the mail relay control part 24, and the email transmission part 25 is implement | achieved.

  The e-mail receiving unit 21 has one general-purpose receiving port 21-0 and dedicated receiving ports 21-1 to 21-n corresponding one-to-one to the additional service servers 3-1 to 3-n. The receiving port has a function of receiving electronic mail using SMTP, which is an Internet standard.

  The general-purpose receiving port 21-0 is a port that receives packets sent from the user terminal 5 and the other mail server 6 to the mail server 1. Since the mail server 1 normally uses the port with the port number “25” to receive and send mail to the mailbox 7, the port number “25” is used as the general-purpose receiving port of the e-mail receiving unit 21. By directing to 21-0, the mail sent to the mail server 1 is first received at the general-purpose receiving port 21-0. Mail received at the general reception port 21-0 is handled as mail to which no additional service has been applied yet. Note that the port number “25” of the mail server 1 has been changed to another port number, and mail is sent from the e-mail proxy device 2 to the port after the change. .

  The dedicated reception ports 21-1 to 21-n are ports that receive mail sent from the additional service servers 3-1 to 3-n. Each additional service server 3-1 to 3-n has a one-to-one correspondence with its own server when applying the additional service to the received mail and returning the mail to the electronic mail proxy device 2. The mail is transmitted to the dedicated reception ports 21-1 to 21-n. In this embodiment, the type of additional service applied to the mail is determined based on the dedicated reception port 21-i (i is any one of 1 to n) that has received the mail. Specifically, the determination is made as follows.

  Each of the additional service servers 3-1 to 3-n provides a predetermined type of additional service. When the types of additional services provided by the additional service servers 3-1 to 3-n are A1 to An, the application order is fixed in advance as A1 → A2 →. For example, in the case of a mail subject to application of three additional services A1, A2, and An, first, the additional service of A1 is applied first, then the additional service of A2 is applied, and finally the additional service of An is applied. . The additional service is never applied in an order different from the predetermined order such as A2 → A1 → An or An → A1 → A2. Therefore, if a mail subject to the application of the three additional services A1, A2, and An is received at the receiving port 21-2, the additional services of A1 and A2 have already been applied, and the additional service of An is not yet available. It can be recognized that this is an application. This embodiment uses such a mechanism to manage whether or not an additional service is applied to an e-mail without performing any processing such as adding a special header to the e-mail itself.

  When the e-mail receiving unit 21 receives mail at the receiving ports 21-0 to 21-n, the e-mail receiving unit 21 secures one data structure on the storage unit 26, and records the received mail information in the data structure. Then, the sender / receiver discriminating unit 22 is notified of the data structure in which the received mail information is recorded. The notification of the data structure is performed by, for example, notifying the start address and size.

  Referring to FIG. 3, the data structure 260 secured on the recording unit 26 includes a reception port information storage area 261, a sender information storage area 262, a receiver information storage area 263, and an e-mail data storage area 264. The The e-mail receiving unit 21 stores the received mail in the e-mail data storage area 264 and stores information (for example, port numbers) of the receiving ports 21-0 to 21-n that received the mail in the receiving port information 261. The sender information storage area 262 and the receiver information storage area 263 are set to NULL.

  The sender / receiver discriminating unit 22 reads the data structure 260 notified from the email receiving unit 21 from the storage unit 26, analyzes the header information of the email recorded in the email data storage area 264, and transmits the data structure 260. Information identifying the recipient and information identifying the recipient. The information specifying the sender and the receiver is, for example, an e-mail address. Then, the sender / receiver discriminating unit 22 records information specifying the sender in the sender information storage area 262 of the data structure 260 and stores information specifying the receiver in the receiver information storage area 263 of the data structure 260. Record. Here, when there are a plurality of mail recipients, the data structures 260 are copied to generate as many data structures 260 as the number of mail recipients on the storage unit 26, and the recipients and data structures are set to 1 Correspond to pair 1. Since the header information of the e-mail may be spoofed, as a method for specifying the sender and receiver of the mail, a method for specifying the sender by authentication (SMTP-AUTH) during SMTP communication, and the SMTP protocol The recipient identification method based on the envelope information may be used.

  The sender / receiver discriminating unit 22 notifies the customer information inquiry unit 23 of the data structure 260 in which information specifying the sender and the receiver is set.

  The customer information inquiry unit 23 reads the notified data structure 260 from the storage unit 26, and specifies information specifying the sender from the sender information storage area 262 and information specifying the receiver from the receiver information storage area 263. Each is retrieved, and the internal cache 231 is searched for the sender and the receiver using the information for identifying them as a key. For each piece of information (such as an e-mail address) that identifies each user, information (types of additional services with which the user has a contract for use) acquired from the customer management system 4 within a certain past period is recorded in the cache 231. Yes. If the search of the cache 231 is successful, the subsequent processing is executed using the type of additional service searched. If the search of the cache 231 fails, information specifying the sender and receiver is added, and customer information is inquired of the customer management system 4.

  In the customer information database 8, for example, customer information including at least the type of additional service with which the user has a use contract is recorded for each piece of information (e-mail address or the like) specifying each user. The customer management system 4 searches the customer information database 8 using the information specifying the sender / receiver added to the inquiry request sent from the customer information inquiry unit 23 as a key, and the additional service that the user has a usage contract with. Is returned to the customer information inquiry unit 23 as an inquiry result. The customer information inquiry unit 23 registers the type of additional service with which the sender / receiver has a usage contract obtained in the inquiry in the cache 231 for later reuse.

  When the customer information inquiry unit 23 acquires the type of additional service with which the sender and the receiver have a usage contract as described above, the customer information inquiry unit 23 transmits the type of additional service with which the sender has a usage contract to the data structure 260. Is recorded in the receiver information storage area 262, and the type of the additional service with which the receiver is contracted is recorded in the receiver information storage area 263 of the data structure 260. Then, the mail relay control unit 24 is notified of the data structure 260 in which the types of additional services with which the sender and the receiver are subscribed are set.

  The mail relay control unit 24 reads the notified data structure 260 from the storage unit 26, stores the type of additional service with which the sender has a usage contract stored in the sender information storage area 262, and receiver information storage The type of the additional service with which the receiver stored in the area 263 is subscribed, the reception port information stored in the reception port information storage area 261, and the application order of the additional service determined in advance by the system Based on this, it is determined whether or not the additional service to be executed for the mail stored in the electronic mail data storage area 264 remains, and if it remains, which is the next additional service to be executed. If there is no additional service to be determined and determined to be executed, the mail relay destination is determined to be the mail server 1, and if it remains, the mail relay is determined. Then determining the additional service server to provide additional services to be performed. Then, the determined relay destination and the data structure 260 are specified, and the e-mail transmission unit 25 is requested to send a mail.

  FIG. 4 shows a flowchart of processing in which the mail relay control unit 24 determines a mail relay destination. If the port that received the mail is the general-purpose reception port 21-0 (YES in step S1-0), since no mail has yet been applied to the additional service, the sender and the receiver make a usage contract in order from type A1. The types of additional services that are present are checked (steps S2-1 to S2-n). Here, in the present embodiment, when at least one of the sender and the receiver has subscribed to the additional service of the type Ai (i = 1 to n), the determination in steps S2-1 to S2-n Is true (YES). Therefore, for example, when the sender or the receiver has a contract for using the additional service of type A1, the determination in step S2-1 is true and the additional service server 3-1 is determined as the relay destination (step S3). -1). If neither the sender nor the receiver has a usage contract of type A1, then the presence of a usage contract for the additional service of type A2 is checked (step S2-2). If any of them has a usage contract for the additional service of type A2, the additional service server 3-2 is determined as a relay destination (step S3-2). If the sender or receiver does not have a usage contract, the process proceeds to steps S4 through steps S2-1 to S2-n, and the mail server 1 is determined as a relay destination.

  Further, when the port that received the mail is the dedicated reception port 21-1 (YES in step S1-1), since the mail has already received the application of the additional service of the type A1, the sender / receiver sequentially starts from the remaining type A2. The type of additional service for which a usage contract is made is checked (steps S2-2 to S2-n). For example, if the sender or the receiver does not have a contract for using the additional service of types A2 to An-1, but has a contract of using the additional service of type An, the determination in step S2-n is true. The additional service server 3-n is determined as the relay destination (step S3-n). If neither the sender nor the receiver has a usage contract of types A2 to An, the process proceeds to step S4 via steps S2-1 to S2-n, and the mail server 1 is determined as a relay destination. .

  As described above, when the port that received the mail is the dedicated reception port 21-i, the mail relay control unit 24 checks the types of additional services that the sender / receiver subscribes to in order from the type Ai + 1. Of these, the additional service server that provides the additional service with the earliest application order is determined as the relay destination, and if there is no usage contract, the mail server 1 is determined as the relay destination.

  The e-mail transmission unit 25 includes a transmission port 25-0 for transmitting mail to the mail server 1 and transmission ports 25-1 to 25-n for transmitting mail to the additional service servers 3-1 to 3-n. When the notification specifying the determined relay destination and the data structure 260 is received from the mail relay control unit 24, the notified data structure 260 is read from the storage unit 26, and the transmission ports 25-0 to 25- From n, it is transmitted to the notified relay destination.

  FIG. 5 is a block diagram of the main part of an electronic mail system according to another embodiment of the present invention. In the present embodiment, a plurality of e-mail proxy devices 2-1 to 2-m are provided in parallel before the mail server 1, and mail sent from the user terminal 5 and other mail server 6 to the mail server 1 and the additional service server The mail returned from 3-1 to 3-n is received by the load balancer 10, and the load balancer 10 makes the load of the plurality of electronic mail proxy devices 2-1 to 2-m substantially equal. The mail is distributed to the electronic mail proxy devices 2-1 to 2-m.

  The load distribution apparatus 10 has one general-purpose reception port 10-0 and dedicated reception ports 10-1 to 10-n corresponding to the additional service servers 3-1 to 3-n on a one-to-one basis. The port has a function of receiving e-mail using SMTP, which is an Internet standard. Here, the port number of the general-purpose receiving port 10-0 is “25”, and is a port that receives mail sent from the user terminal 5 and the other mail server 6 to the mail server 1 by proxy. The load distribution apparatus 10 transmits mail received at the general-purpose reception port 10-0 from the transmission port 11-0 to the reception ports 21-0 of the electronic mail proxy apparatuses 2-1 to 2-m, and the dedicated reception port 10-1. 10-n, the receiving ports 21-1 to 21-n of the e-mail proxy devices 2-1 to 2-m are sent from the sending ports 11-1 to 11-n corresponding to the ports one to one. Send to.

  The e-mail proxy devices 2-1 to 2-m perform basically the same configuration and operation as the e-mail proxy device described in FIG. However, the reception port 21-0 is not a port number “25”, but a port of any other number is used.

  In the electronic mail system according to the present embodiment, a mail sent from the user terminal 5 or another mail server 6 to the mail server 1 is received by the general-purpose reception port 10-0 of the load distribution apparatus 10, and the transmission port 11 -0 to any e-mail proxy device, for example, the reception port 21-0 of the e-mail proxy device 2-1. The electronic mail proxy device 2-1 performs the same processing as the electronic mail proxy device 2 shown in FIG. 2, and determines the type of additional service to be applied to the received mail.

  Assuming that the additional services to be applied are types A1 and A2, the e-mail proxy device 2-1 relays mail from the transmission port 25-1 to the additional service server 3-1. The additional service server 3-1 executes the type A 1 additional service for the received mail, and transmits the mail to the dedicated reception port 10-1 of the load balancer 10 when returning the mail. The load balancer 10 transmits the mail received at the dedicated reception port 10-1 from the transmission port 11-1 to any of the email proxy devices, for example, the dedicated reception port 21-1 of the email proxy device 2-m. .

  The e-mail proxy device 2-m performs the same process as the e-mail proxy device 2 shown in FIG. 2, determines the type A2 as the type of additional service to be applied to the received mail, and sends the transmission port 25-2. Relay the mail to the additional service server 3-2. The additional service server 3-2 executes the additional service of type A2 on the received mail, and transmits the mail to the dedicated reception port 10-2 of the load balancer 10 when returning the mail. The load distribution apparatus 10 transmits the mail received at the dedicated reception port 10-2 from the transmission port 11-2 to any of the electronic mail proxy devices, for example, the dedicated reception port 21-2 of the electronic mail proxy device 2-1. .

  The e-mail proxy device 2-1 performs the same processing as the e-mail proxy device 2 shown in FIG. 2, determines that there is no additional service to be applied to the received mail, and starts from the transmission port 25-0. The mail is relayed to the receiving port of the mail server 1.

  Thus, according to the present embodiment, it is possible to efficiently distribute the load of the electronic mail proxy device.

  Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various other additions and modifications can be made. For example, in steps S2-1 to S2-n in FIG. 4, the determination is made based on the usage contracts of both the sender and the receiver, but the determination is made based on the usage contract of only the sender and vice versa. The determination may be made based on the use contract only for the user.

  As described above, the e-mail proxy device according to the present invention is used for a purpose such as passing only a mail transmitted by a contract user or a mail received by the contract user through a server that performs an additional service such as a virus check. Suitable for

1 is a block diagram of an electronic mail system according to an embodiment of the present invention. It is a block diagram which shows an example of the electronic mail proxy apparatus of this invention. It is a block diagram of the data structure ensured on the recording part of the electronic mail proxy apparatus of this invention. It is a figure which shows the flowchart of the process in which the mail relay control part in the electronic mail proxy apparatus of this invention determines the relay destination of mail. It is a principal part block diagram of the electronic mail system concerning another embodiment of this invention. It is a block diagram of a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Mail server 2, 2-1 to 2-m ... E-mail proxy device 3-1 to 3-n ... Additional service server 4 ... Customer management system 5 ... User terminal 6 ... Other mail server 7 ... Mail box 8 ... Customer Information database 9 ... recording medium 10 ... load distribution device 10-0 ... general reception port 10-1 to 10-n ... dedicated reception port 11-0 to 11-n ... transmission port 21 ... email receiving unit 21-0 ... general purpose Receiving ports 21-1 to 21-n ... dedicated receiving port 22 ... transmitter / receiver discriminating unit 23 ... customer information inquiry unit 24 ... mail relay control unit 25 ... email sending unit 25-0 to 25-n ... sending port 26 ... memory Unit 231 ... Cache 260 ... Data structure 261 ... Receiving port information storage area 262 ... Sender information storage area 263 ... Receiver information storage area 264 ... E-mail data storage area

Claims (7)

  It is installed in the front stage of a mail server that provides a service for receiving mail sent from a user terminal and another mail server using SMTP and distributing it to another mail server or storing it in a mailbox. Receives incoming e-mails on behalf, determines additional services with which the mail sender or mail recipient has a usage contract, and executes control to relay the mail to the additional service server that provides the determined additional services An e-mail proxy device that transmits an e-mail for which application of additional services has been completed to the mail server. An e-mail proxy device installed in the front stage of a mail server that receives mail sent from a user terminal and another mail server using SMTP and distributes the mail to another mail server or stores it in a mailbox Because
Mail sent to the mail server by SMTP communication is received at the general-purpose receiving port on behalf of the mail server, and mail sent from the external additional service server is received for each additional service server in advance. A mail receiver to receive on the port;
A sender / receiver discriminating unit for discriminating at least one of a sender and a recipient of the mail received by the mail receiving unit;
A customer information inquiry section that checks the types of additional services the user has subscribed to,
Whether or not there is an additional service to be executed for the mail based on a predetermined application order of the additional service, the type of the additional service found by the customer information inquiry unit, and the type of the reception port of the mail And if it remains, it is determined which additional service to be executed next, and if there is no additional service to be executed, the mail server is determined as the mail relay destination, A mail relay control unit that determines an additional service server that provides an additional service to be executed next if the mail relay destination remains;
An e-mail proxy device comprising: a mail transmitting unit that transmits the mail to a relay destination determined by the mail relay control unit.   In place of the mail receiver, the mail distributed from the load balancer that receives mail sent to the mail server by SMTP communication at the general reception port on behalf of the mail server is received at the reception port; And a mail receiving unit that receives mail transmitted from an external additional service server, received by the load balancer, and distributed from the load balancer at a dedicated reception port predetermined for each additional service server. The electronic mail proxy device according to claim 2.   The customer information inquiry unit inquires a customer management system that manages the type of additional service with which the user is subscribed to the type of additional service with which the user has been subscribed to the use determined by the sender / receiver discrimination unit. The e-mail proxy device according to claim 2 or 3. An e-mail proxy device installed in the front stage of a mail server that receives mail sent from a user terminal and another mail server using SMTP and distributes the mail to another mail server or stores it in a mailbox The computers that make up the
Mail sent to the mail server by SMTP communication is received at the general-purpose receiving port on behalf of the mail server, and mail sent from the external additional service server is received exclusively for each additional service server. Mail receiving means to receive at the port,
A sender / receiver discriminating means for discriminating at least one of a sender and a recipient of the mail received by the mail receiving means;
Customer information inquiry means to find out the types of additional services the user has subscribed to,
Whether or not there is an additional service to be executed for the mail based on a predetermined application order of the additional service, the type of the additional service determined by the customer information inquiry means, and the type of the reception port of the mail And if it remains, it is determined which additional service to be executed next, and if there is no additional service to be executed, the mail server is determined as the mail relay destination, Mail relay control means for determining an additional service server that provides an additional service to be executed next if the mail relay destination remains,
Mail sending means for sending the mail to the relay destination determined by the mail relay control means;
Program to function as.   In place of the mail receiving means, the computer receives the mail distributed from a load balancer that receives mail sent to the mail server by SMTP communication at a general-purpose receiving port instead of the mail server. As a mail receiving means for receiving mail received from the external load service server, received by the load balancer and distributed from the load balancer at a dedicated receive port predetermined for each load service server, 6. The program according to claim 5, wherein the program is made to function.   The customer information inquiry means inquires of a customer management system that manages the type of additional service with which the user has a usage contract about the type of additional service with which the user has been contracted with the use determined by the sender / receiver discrimination unit. The program according to claim 5 or 6.

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