JP2002314611A - Method and program for transferring e-mail and, mail server - Google Patents

Abstract

PROBLEM TO BE SOLVED: To transfer whole of or a portion of an e-mail to a different LAN and also to prevent the retransfer of a transferred e-mail in a LAN having a firewall. SOLUTION: In the LAN 10-1 storing a plurality of pieces of e-mail, when a transmission request for index information is received, the index information is extracted from the plurality of pieces of e-mail to a user who desires transfer and transmitted as index mail to a LAN 10-n. In the LAN 10-n, information that is not requested to be transferred is removed from the index information shown by the index mail, and the index mail is returned to the LAN 10-1 as a transfer request. In the LAN 10-1, e-mail (or part) shown by the index information that the transfer request has is transferred to the LAN 10-n extracted from a mail box.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic mail transfer method for transmitting and receiving electronic mail on the Internet, a mail server, and an electronic mail transfer program.

[0002]

2. Description of the Related Art Electronic mail is widely used as a communication tool used for network communication. When sending and receiving electronic mail, the mail received by the mail server is temporarily stored in a mailbox. The mail client is referred to using a communication protocol such as POP3 or IMAP4 used for receiving an electronic mail.

[0003] Many users of the e-mail system have a plurality of e-mail addresses, and a LAN (Local Area Network) provided in a workplace or the like.
k) The use of a plurality of e-mail addresses depending on the place of use, equipment used, purpose of use, etc., such as an information processing terminal at home connected to an Internet provider or a portable terminal capable of displaying a web page. ing.

By the way, a firewall is often installed between the Internet and the Internet in order to prevent unauthorized access, intrusion, eavesdropping, and the like on a corporate LAN. This firewall uses a simple method that allows only specific packets to pass through the identification of an IP mail address, and a proxy server (Proxy server).
Various protection methods are used, such as a method using a password and a method using a very complicated authentication mechanism.

[0005] In particular, in the case of the Internet or the like which is an open network, hacking from a LAN or the like connected to the Internet or the like is likely to cause unauthorized intrusion. Therefore, instead of prohibiting access from external organizations, e-mail service providers that handle e-mail provide a service that sets e-mail forwarding destinations in advance and forwards them periodically or when an e-mail arrives. Have been.

[0006]

However, when an electronic mail is transferred by a service of a provider or the like, there are the following problems. For example, when a firewall is installed in the LAN of the transfer source or transfer destination of the e-mail, it is often impossible to refer to the e-mail from outside the organization using POP3 or IMAP4.

Further, in order to transfer an e-mail arriving at the own LAN to another LAN, it is necessary to set a transfer destination in advance in an organization having the own LAN.
In addition, in order to set a transfer destination from a network outside the organization, there is a restriction that a dedicated protocol having high security must be used. For example, it is difficult to set a transfer from a terminal having only a mail function such as a portable terminal.

Further, the mail server cannot identify whether the stored electronic mail has already been transferred. Therefore, when there is a transfer request,
Have to forward all emails,
There was a problem that only emails that arrived after forwarding settings were forwarded.

[0009] In recent years, the demand for mail transfer by service providers has increased due to the spread of mobile terminals and the like equipped with electronic mail software. Volume) and mail size (transfer size). For this reason, there has been a need for a proposal of a technology that allows a user who receives this service, not a provider that provides the transfer service, to select whether or not to forward an e-mail.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and it is possible to transfer all or a part of an e-mail without lowering the security strength of a firewall, and to resend the transmitted e-mail. It is an object of the present invention to provide an e-mail transfer method, a mail server and an e-mail transfer program, which prevent transmission and allow a user who desires transfer to select a transfer mail.

A conventional example capable of transferring an e-mail without impairing the security function of the firewall is disclosed in Japanese Patent Application Laid-Open No. 9-233115 as an e-mail transfer device, and in Japanese Patent Application Laid-Open No. 11-266279 as an e-mail management system. And JP-A-2000-1486.
No. 11 discloses an intranet, a database server, and a data transfer method thereof.

The electronic mail transfer device, the electronic mail management system, and the intranet, the database server, and the data transfer method disclosed in these publications can transfer the entire electronic mail. It is not possible to transfer only a copy. Therefore, even in these conventional examples, the above object could not be achieved.

[0013]

In order to achieve the above object, an electronic mail transfer method according to claim 1 of the present invention transfers an electronic mail having a mail text and an attached file from one network to another network. An e-mail transfer method, wherein one network creates an index mail indicating a list of e-mails, the other network receives the index mail, and generates an index mail indicating the list of e-mails indicated by the received index mail. Select the email requesting transfer from and make it a transfer request,
One network is a method of receiving a transfer request and transferring an e-mail indicated by the received transfer request to another network.

If the electronic mail transfer method is such a method, it is possible to know whether or not the electronic mail has reached one network in another network by the index mail. Then, of the index information indicated in the index mail, the one desired to be transferred can be selected, the one not transferred is deleted and returned to one network. Can be selected.

[0015] Further, since one or more electronic mails indicated by the transfer request are transferred from one network in another network, a user of another network can view the transferred electronic mail. Therefore, it is possible to confirm the presence / absence of arriving mail and make a mail transfer request from another network to a mail server of one network whose access from another organization is restricted by a firewall or the like.

In the electronic mail transfer method according to the second aspect, each of the mail body and the attached file is a part, and one network stores a list of parts included in each of the stored electronic mails in an index mail. The other network selects a part requesting transfer from the list of parts indicated by the received index mail and sets it as a transfer request, and one network transfers the part indicated by the received transfer request to another network. There is a way to transfer.

If the e-mail transfer method is such a method, a list of parts is described in the index mail, so that users of other networks desire transfer not only for each e-mail but also for each part. be able to. That is, not only the entire e-mail but also a part of the e-mail can be transferred.

Further, in another network, by deleting the index information relating to the part indicated in the index mail, the index information which has not been deleted is selected as a transfer-desired part, and the selected part is transferred to one network. Is transferred from
The user can make the selection by using an e-mail editing function of a general mail client installed in another network. Therefore, without the need for additional special equipment
In a mail client equipped with electronic mail software, it becomes possible to select a transfer desired part in an index mail, browse the transferred mail, and the like.

According to a third aspect of the present invention, there is provided an electronic mail transfer method, wherein the electronic mail has a transferred field for recording a transferred part, and one network has each of the stored electronic mails. Indicate all the parts to be described in the index mail for all the parts, and write in the index mail the parts of each saved e-mail that are not recorded in the forwarded field An index mail that has an untransferred part description instruction address instructing to perform an index mail requesting transmission of an index mail addressed to either the all part description instruction address or the untransfer part description instruction address. Send a transmission request to one network, and Over click is based on the received index mail transmission request destination and has been all the parts described instruction address or untransmitted part according instruction address instructions and indexed mail is a method of transmitting to the another network.

Assuming that the electronic mail transfer method is such a method, when a user of another network transmits an index mail transmission request transmitted from another network to one network, transmission of the index mail transmission request is performed. As the destination, either one of the instruction addresses described in all parts or the instruction addresses described in untransferred parts can be selected.

For this reason, when it is determined that the amount of electronic mail data stored in the mailbox of one network is large, the transmission of the index mail transmission request is performed in consideration of the transmission amount and transmission time of the index mail. You can select the destination email address. Therefore, especially in a portable terminal or the like charged according to the transmission amount or the mail size, the communication cost can be reduced by selecting the instruction address described in the untransferred part instead of the instruction address described in all parts.

According to a fourth aspect of the present invention, there is provided the electronic mail transfer method, wherein one network instructs all the untransferred parts of the stored electronic mails to be transferred. It has a transfer instruction address and a designated part transfer instruction address for instructing to transfer the part described in the index mail among the parts of each of the stored e-mails, and all the other networks have A transfer request is transmitted to one network with either the transfer instruction address or the designated part transfer instruction address as a destination, and the one network transmits all part transfer instruction addresses or designated part transfer addressed to the received transfer request. Extract parts from each of the stored e-mails based on the instruction address Is a method of transferring to another network.

If the electronic mail transfer method is such a method, when a user of another network transmits a transfer request transmitted from another network to one network, a user of the transfer request transmits Either all part transfer instruction address or designated part transfer instruction address can be selected.

For this reason, when it is determined that the amount of electronic mail data stored in the mailbox of one network is large, the transmission destination mail address of the transfer request is considered in consideration of the transfer amount and transfer time of the part. Can be selected.
Therefore, especially in a portable terminal or the like charged according to the transfer amount or the transfer size, the communication cost can be reduced by selecting the designated part transfer instruction address instead of the all part transfer instruction address.

According to a fifth aspect of the present invention, in the electronic mail transfer method, the index mail describes the identification information of the electronic mail included in the part and the attached file information such as the file name, format and size of the attached file as the index information. There is a way to do it. If the e-mail transfer method is such a method, the user who wants to transfer can refer to the index information described in the index mail and select / delete unnecessary or large-sized parts efficiently. And can be done freely.

The identification information of the electronic mail includes a message ID (Message-I) for uniquely identifying the mail.
d), From indicating the sender, Date indicating the sending date and time
Alternatively, the information may include information for identifying an e-mail typified by a subject indicating a title. Further, the attached file information can include information about the attached file represented by the file name, file format, size, or distinction between the text and the attached file of the attached file.

According to a sixth aspect of the present invention, there is provided an electronic mail transfer method in which a transferred field records a mail address to which a part has been transferred, together with a part which has already been transferred. If the e-mail transfer method is such a method, when the transfer applicant has three or more mail addresses, the already transferred e-mail can be transferred to another mail address.

Since the mail address once used for transfer is recorded in the transferred field, it is not used again as a destination. Therefore, the efficiency of e-mail transfer can be improved.

A mail server according to a seventh aspect of the present invention is a mail server having a mailbox for storing electronic mail, an index information processing section for creating an index mail showing a list of electronic mails, The index mail created by the processing unit
A transmission unit for transmitting to another server or a mobile terminal, and reception for receiving, as a transfer request, one or two or more e-mails selected from a list of e-mails indicated by the index mail in the other server or the mobile terminal. And a transfer request processing unit that extracts one or more e-mails indicated by the transfer request from the receiving unit from the mailbox and transfers the e-mail to another server or portable terminal.

When the mail server has such a configuration,
Since the mail server has a function of transmitting the index information to the mail server of the transfer destination, a function of transferring the e-mail specified by the index mail, and the like, the access to the mail server from another organization is restricted by, for example, a firewall. Even if the e-mail to save can be forwarded.

An electronic mail transfer program according to claim 8 is an electronic mail transfer program for causing one network to execute a process of transferring an electronic mail having a mail text and an attached file from one network to another network. Then, an index mail indicating the list of e-mails is created, the created index mail is transmitted to another network, and one or two selected from the list of e-mails indicated by the index mail are sent to the other network. The above-described electronic mail is received as a transfer request, and the process of transferring one or more electronic mails indicated by the received transfer request to another network is executed by one network.

If the electronic mail transfer program has such a configuration, processing for creating an index mail, processing for transmitting the index mail, processing for receiving a transfer request, and processing for sending an electronic mail or part described in the transfer request to another One network can execute processing such as transfer to a network. For this reason, it is possible to cause one network in which the electronic mail transfer provider and the computer cooperate to execute the electronic mail transfer processing.

[0033]

Embodiments of the present invention will be described below with reference to the drawings. First, an embodiment of an electronic mail transfer method, a mail server, and an electronic mail transfer program according to the present invention will be described with reference to FIG. FIG. 1 is a block diagram showing the configuration of the electronic mail transfer system of the present embodiment.

As shown in FIG. 1, the electronic mail transfer system 1 includes a plurality of LANs (Localarea networks).
ork) 10-1, 10-2, ..., 10-m, 10
-N (LAN 10-1 to 10-n) and the mobile terminal 20
, Relay station 30, communication network 40, communication network 50
And Here, LANs 10-1 to 10-n
Are mail servers 11-1 to 11-n, mail clients 12-1 to 12-n, and a firewall 13-
1 to 13-n.

The mail servers 11-1 to 11-n are configured as shown in FIG.
As shown in the figure, the mailbox management units 11-1-1 to 1-1-1
1-n-1 and mailboxes 11-1-2 to 11-n
-2, transferred field processing units 11-1-3 to 11-
n-3 and mail address determination units 11-1-4 to 11-
n-4 and the index information processing units 11-1-5 to 11-11
-N-5 and transfer request processing units 11-1-6 to 11-n-
6 and transmission / reception units 11-1-7 to 11-n-7.

Mailbox management units 11-1-1 to 11-11
-N-1 is a mail address determination unit 11-1-4 to 11-1
The e-mail determined to be a normal e-mail in -n-4 is sent to the mailboxes 11-1-2 to 11-n-2 for storage. Also, the mailbox management unit 11-1-1
To 11-n-1 are transferred field processing units 11-1-n
3 to 11-n-3, index information processing section 11-1-
5-11-n-5 and transfer request processing section 11-1-6-1
Based on a command from 1-n-6, a predetermined e-mail is extracted from the mailboxes 11-1-2 to 11-n-2 and sent to each component.

The instructions from each component include, for example,
A mail from the index information processing section 11-1-5 to 11-n-5, which has not been subjected to the index information transmission processing, is sent to the mailbox 11-1-2 based on the instruction to start the index information transmission processing. ~ 11-n
-2.

Mailboxes 11-1-2 to 11-n-
2 is a mailbox management unit 11-1-1 to 11-n-
Save the email from 1. In addition, index information from the index information processing units 11-1-5 to 11-n-5 can be stored. Note that LAN10-
In the case where the owners or managers of 1 to 10-n are e-mail management companies represented by providers or the like, users of the e-mail service are registered in the e-mail management companies and the registered users Mailboxes 11-1-1 to 11-n-1 are provided for each.

Also, the mailboxes 11-1-2 to 11-11
-N-2 indicates the mail servers 11-1 to 11-1 in FIG.
11-n, the mail server 11
Not limited to the inside of -1 to 11-n, an independent server different from the mail servers 11-1 to 11-n is provided,
This server can be used as a mailbox.

Transferred field processing units 11-1-3-1
1-n-3 records the transferred part name in the transferred field provided in the electronic mail. FIG. 3 shows an image of an electronic mail having a transferred field. As shown in the figure, the electronic mail is composed of a transferred field, a header part, and a mail body. The mail body is composed of a mail text and an attached file. In the present invention, the mail body has a mail text, an attached file “a.dat”, and an attached file “b.dat”.

Further, in the present invention, each of the mail body and the attached file constituting the mail body is referred to as a part. That is, in the e-mail shown in FIG.
The attached file “a.dat” corresponds to Part2, and the attached file “b.dat” corresponds to Part3.
Note that, although the electronic mail has three parts in the figure, the number is not limited to three and may be any number.

The transferred field shown in FIG.
Part1 and Part3 are recorded, and this recording indicates that Part1 and Part3 have already been transferred. The recording of the transferred part is not limited to the transferred field provided separately from the header part and the mail body in the electronic mail. For example, a method of recording the part in the header part can be adopted.

In the present invention, the electronic mail is processed for each part. The process is that the email
RFC2045 (Request for comme
mts 2045).
ipurose internet mail ex
(Tensions) format or the like.

Further, in the transferred field, a transfer destination mail address can be added together with the transferred part. When a transfer destination mail address is added to a transferred part in the transferred field, the transfer destination part can be controlled independently for each transfer destination.

For example, when the user A receives the first and second L
If a third LAN is available in addition to the AN, that is, user A is in the first (userA@abc.co.j
p), when the second (userA@home.ne.jp) and third (userA@xyz.com) mail addresses have been obtained, and only the transferred part can be recorded in the transferred field. Is part 1 us
erA @ home. ne. jp only and recorded in the transferred field, then userA @ xyz. com is not transferred even if there is a transfer request.

However, if it is possible to add a transfer destination e-mail address to a transferred part in the transferred field, the part 1 is userA @ home. n
e. jp, but already transferred to userA
{Xyz. com is determined not to have been forwarded to userA@xyz.com. When there is a transfer request to com, the part 1 is transferred to this mail address.

Mail address judging sections 11-1-4 to 11-11
-N-4 is a normal e-mail or requests a predetermined process based on the instruction content indicated by the e-mail address of the e-mail received by the transmission / reception units 11-1-7 to 11-n-7. Determine if it is an email. If the result of this determination is that the e-mail is a normal e-mail, the e-mail is sent to the mailbox management units 11-1-1 to 1-1-1.
Mailboxes 11-1-2 to 11-1 through 1-n-1
-Send to n-2 for storage.

On the other hand, when it is determined that the electronic mail is a request for a predetermined process, the index information processing units 11-1-5 to 11-n-5 and the transfer request processing unit 11-1-6 are based on the processing contents. To 11-n-6 are transmitted (index information creation command and transfer request command).

The mail address used for this determination includes an address for instructing all the parts included in each of the stored electronic mails to be described in the index mail,
Of the parts of each of the stored e-mails, for the parts not recorded in the transferred field, an untransferred part designation instruction address for instructing to be described in the index mail, and the stored Of the parts of each of the e-mails, an all-part transfer instruction address for instructing to transfer all of the untransferred parts, and the index mail of the parts of each of the stored e-mails There are a designated part transfer instruction address for instructing to transfer the specified part, and a mail address other than these.

In the present invention, the instruction address for all parts, the instruction address for untransferred parts, the instruction address for all parts transfer, and the instruction address for designated part transfer are referred to as function requests. The details of the determination based on these function requests and an example of a mail address used as a function request will be described later. In addition, a method of requesting a function such as an index information transmission request or an e-mail transfer request may be a method of designating the subject of the mail or the body of the mail instead of the mail address.

Index information processing section 11-1-5-1
1-n-5 is a mail address judging section 11-1-4 to 1-1
Based on the index information creation command from 1-n-4, index information and index mail are created. The index information is created by extracting the header part of the e-mail shown in FIG. 3 and the outline elements of each part.

As shown in FIG. 4, as examples of information constituting the index information, From header, which is the source information of the e-mail, Message-ID for uniquely identifying the e-mail, title of the e-mail S indicating
object, Da indicating the date on which the e-mail was sent
te header, information (element) of each part, and the like.

As shown in FIG. 4, a text size can be added to the information of each part of the index information. For example, for Part 1 (Part 1), the text in ISO 2202-JP format is 1 KB.
It is part 2 (Part 2)
For the file name a. The size of 10 KB in the attached file of dat is further described in Part 3 (P
art3), the file name is b. The attached file of "dat" has a size of 5 KB, respectively.

In the index mail, index information on a plurality of electronic mails is described. The index information to be described is, for example, as shown in FIG.
420 @ xxx. co. jp>, <3A388D862
3F. 208 @ yyy. co. jp>, <200012
150642. PAA06298 @ zzzz. co. jp
> For three e-mails having the Message-ID.

The contents of the index information related to the electronic mail differ depending on the type of the mail address indicating the index information transmission request. For example, the e-mail address is the instruction address described in the untransferred part (for example,
If it is (user name-index @ domain name), only the information (element) of the untransferred part is described in the index mail.

As an example, of the index information described in the index mail shown in FIG.
age-ID is <09796957020.002869
4420 @ xxx. co. As for the e-mail of jp>, as shown in FIG. 3, since part 1 and part 3 are described in the transferred field, only untransferred part 2 is described in the index mail of FIG.
Parts 1 and 3 are not described.

However, since all the parts included in this electronic mail are described in the transferred field, if there is no part that can be described in the index mail, the index information itself is not described. When the mail address is an instruction address for describing all parts (for example, user name-index-all @ domain name),
Information (elements) of all parts is described in the index mail.

As an example, of the index information described in the index mail shown in FIG.
age-ID is <200012150642. PAA0
6298 @ zzzz. co. jp>, all parts (part 1 and part 2) of the e-mail are described.

The index mail is a mail of the LAN (for example, LAN 10-n) that has transmitted the electronic mail of the index transmission request after being created by the index information processing units 11-1-5 to 11-n-5. Sent to a client (e.g., mail client 12-n). In this mail client 12-n,
Lines that do not need to be transferred are deleted from the description of the index mail, and are returned to the LAN (for example, LAN 10-1) that transmitted the index mail.

The transfer request processing units 11-1-6 to 11-n-
6 is a mail address judging unit 11-1-4 to 11-n-
4, a predetermined e-mail is taken out of the mailboxes 11-1-2 to 11-n-2 via the mailbox management units 11-1-1 to 11-n-1 based on the transfer request command from the The data is transmitted to predetermined LANs 10-1 to 10-n via 11-1-7 to 11-n-7.

The transfer request command is sent to the mail address determination unit 1
1-1-4 to 11-n-4. The content of the transfer request instruction differs depending on the type of the e-mail address. For example, if the e-mail address is the designated part transfer instruction address (for example, “user name-trans
In the case of "fer @ domain name"), the transfer request command indicates that the stored mail specified by the index information among the untransmitted stored mails is transferred. Also, all part transfer instruction addresses (for example, “user name-trans
In the case of "fer-all @ domain name"), the transfer request command indicates that all unsent stored mail is transferred.

The transmission / reception units 11-1-7 to 11-n-7 are:
It has a function of receiving an e-mail transmitted from another LAN and transmitting the e-mail to another LAN. The transmission / reception units 11-1-7 to 11-n-7 include the index information from the index information processing units 11-1-5 to 11-n-5, the mailbox management unit 11-1-n.
3 is sent to another predetermined LAN.

The transmission / reception units 11-1-7 to 11-n-7
The transmission function among the transmission / reception functions of
(Request for Comments 82
SMTP (Simple mail t) shown in 1)
This is realized by a communication protocol typified by transfer protocol.

On the other hand, the e-mail receiving function is based on RFC1
939 and IMAP4 (Internet message a) described in RFC2060.
access protocol version 4)
It is realized by a communication protocol represented by, for example. In addition, the transmission / reception units 11-1-7 to 11-n-7 can be configured separately by a transmission unit having a transmission function and a reception unit having a reception function.

The mail servers 11-1 to 11-n
In FIG. 1, one is provided for each of the LANs 10-1 to 10-n, and has a function as a transmission / reception mail server. That is, in the LANs 10-1 to 10-n,
Instead of the mail servers 11-1 to 11-n, a transmission mail server (for example, an SMTP server) and a reception mail server (for example, a POP3 server) can be provided.

The mail clients 12-1 to 12-n
Supports SMTP as a mail transmission protocol and POP3 and IMAP4 as a mail reception protocol, and is composed of an information processing device represented by a personal computer or the like. This mail client 1
2-1 to 12-n are, for example, Microsoft
Internet Explorer (trade name) or Ne
Equipped with a general mail reader typified by tscape Communicator (product name) and the like, it is possible to perform operations such as referring to and deleting e-mails stored in the mailboxes 11-1-1 to 11-n-1. it can.

The mail clients 12-1 to 12-12
In -n, the mail addresses of the index transmission request mail and the transfer request mail are selected. The mail address of the index transmission request mail includes an untransferred part writing instruction address and an all-part writing instruction address, and is selected by a user of the mail clients 12-1 to 12-n using a keyboard or the like (not shown).

On the other hand, the mail addresses of the transfer request mail include a designated part transfer instruction address and an all part transfer instruction address.
12-n allows automatic selection of the destination. Many mail clients have a function of automatically selecting an address described in a From header or a Reply-To header as a reply destination when replying to a received mail.

For this reason, for example, the sender of the index mail and “User name-tr” are included in the Reply-To header.
By designating "transfer @ domain name", this address can be automatically selected in the case of a designated part transfer request. The user can select the all-part transfer instruction address using a keyboard or the like.

Note that the From header and the Reply-To
When using the function of automatically selecting the address described in the header as the reply destination, it is possible to avoid sending a mail with index information to all part transfer instruction addresses. However, if the index information is sent to the all-part transfer instruction address by changing the transmission destination by a key input or the like by the user, it is recognized as the all-part transfer instruction, and the index information is ignored.

The firewalls 13-1 to 13-n
This is an information processing device that restricts access beyond each LAN. For example, the firewall 13-1 provided in the LAN 10-1 is connected to the mail client 12-
1 can refer to the mail stored in the mailbox 11-1-2, but access the LAN 10-n from the mail client 12-1 to access the mail stored in the mailbox 11-n-2. References are restricted.

The firewalls 13-1 to 13-
The installation of n is not essential. However, providing all access from all external communication partners, such as the Internet, is vulnerable to malicious attacks, so usually a firewall is installed and only the minimum necessary access methods are used. Restricted to allow.

The mobile terminal 20 is a mobile phone, PHS,
It is composed of PDA and the like. However, since the mobile terminal 20 usually does not have a firewall, the LANs 10-1 to 10-1
The constituent elements are different from 0-n. However, the present invention can be implemented as long as it has an e-mail function.

The relay station 30 transmits and receives a call and a call signal to and from the portable terminal 20. Communication network 40 and 50
Any known public line, commercial line, or dedicated line known in the art can be used, and each can be constituted by the same or different communication lines.

The communication networks 40 and 50 are connected to the mobile terminal 20.
Is a line that allows wireless or wired connection between the relay station 30 and the LANs 10-1 to 10-n. For example, the line can be configured by a mobile terminal network, a public network, a dedicated network, an Internet network, and an intranet network. it can.

Note that the electronic mail transfer system 1 corresponds to FIG.
Has a mobile terminal 20, a relay station 30, and a communication network 50, but is not an essential component. For example, e-mail transfer is performed by LANs 10-1 to 10-n and the communication network 40. The system 1 can also be configured.

Next, the operation (electronic mail transfer method) of the electronic mail transfer system of this embodiment will be described with reference to FIG. FIG. 5 is a flowchart showing the operation of the electronic mail transfer system of the present embodiment.

In the present invention, the LAN that receives the e-mail is the LAN 10-1, the LAN that requests the transfer of the e-mail is the LAN 10-n, and the mail client 13-n of the LAN 10-n operates the transfer request. The user who performs the above operation is a user A, and the LAN for transmitting an e-mail addressed to the user A is LANs 10-2 to 10-m.

A plurality of e-mails transmitted from the LANs 10-2 to 10-m are stored in the mail box 11-1-1 of the mail server 11-1 of the LAN 10-1 in advance. Thereafter, as shown in FIG.
The e-mail sent from AN 10-n is sent to LAN
Transmission / reception unit 11 of mail server 11-1 included in 10-1
Received at -1-7 (step 10).

The received e-mail is sent to the e-mail address judging section 11-1-4, and it is judged whether or not the e-mail address of the e-mail indicates a request for a specific function (step). 11). The e-mail address indicating a request for a specific function includes, for example, “user name-index @ domain name” and “user name-index
-All @ domain name "," user name-transfe
r @ domain name "and" user name-transfe
r-all @ domain name ".

If it is determined that the e-mail address does not indicate a specific function request, the e-mail is sent from the e-mail address judging section 11-1-4 to the mailbox via the mailbox management section 11-1-1. It is sent to 12-1 and stored (step 12). On the other hand, if it indicates a specific function request, then the user of the e-mail is authenticated (step 13).

For user authentication, the mail client 13 of the LAN 10-2 to 10-m, which is the source of the e-mail, is used.
-2-13-m, the mail address described in the From header of the e-mail, and its LAN 10-2
One or both of the sender information automatically added in the mail servers 11-2 to 11-m of 10 to 10-m are used.

However, since the sender information may be spoofed by others, it is desirable to identify the sender by an electronic signature using public key encryption.
As software when using the public key encryption,
RSA's public key encryption method, public key infrastructure P
KI, PGP (Pretty g
wood privacy, an encryption program of PGP).

If the user is not recognized as a valid user as a result of the user authentication, the e-mail is sent to the corresponding user's mailbox 12-1 and stored therein (step 12). Reasons for storing the unauthenticated e-mail include notifying that the transfer could not be performed due to a user error, and notifying the user of the possibility of unauthorized access.

On the other hand, if the user is recognized as a valid user as a result of the user authentication, the mail address judging unit 11-1-4 then sends the mail address indicating the transmission request of the index information, ie, “ User name-
"index @ domain name" or "user name-index
It is determined whether or not “-all @ domain name” (step 14). If the result of the determination is that the request indicates transmission of index information, index information transmission processing is performed (step 15). The index information transmission processing will be described later.

On the other hand, when the mail address does not indicate a transmission request for index information, the mail address further indicates a mail transfer request, that is, “user name-index”.
-All @ domain name "or" user name-transf
It is determined whether or not “er @ domain name” (step 16).

If the result of the determination indicates a mail transfer request, mail transfer processing is performed (step 1).
7). The mail transfer process will be described later. On the other hand, if it does not indicate a mail transfer request, the e-mail is sent from the mail server 11-1 to the mailbox 12-1.
And stored (step 12).

Next, the operation of the index information transmitting process will be described with reference to FIG. Mail server 11-
If the e-mail address determination unit 11-1-4 determines that the e-mail address indicates a transmission request for index information (step 14 in FIG. 6), then
An index information transmission process is performed.

In the index information processing section 11-1-5, which has received an instruction to start the index information transmission processing from the mail address determination section 11-1-4, the mailbox information is transmitted via the mailbox management section 11-1-1. 11-1
It is determined whether or not all the electronic mails (stored mails) addressed to the user A stored in -2 have been subjected to the index information transmission processing (step 30 in FIG. 7).

As a result of the judgment, if there is a stored mail that has not been processed, the stored mail is taken out by the mailbox management section 11-1-1 (step 31).
Sent to index information processing section 11-1-5. Next, the mail address determination unit 11-1-4 determines whether or not the mail address of the electronic mail (index transmission request mail) having the mail address indicating the transmission request of the index information is the instruction address described in the untransferred part. (Step 32).

As a result of the determination, the mail address is the instruction address described in the untransferred part, for example, "user name-in
If "dex @ domain name", the mail address determination unit 11-1-4 sends the index information processing unit 11-1.
To -5, an index information creation command indicating that an index mail is created only with the index information for the untransferred is sent.

In the index information processing section 11-1-5, the electronic mail sent from the mailbox management section 11-1-1 based on the input index information creation command is stored in the transferred field of the electronic mail. It is determined whether there is any part that has not been recorded (step 33).

If the result of the determination is that there is a part that is not recorded in the transferred field, the index information of the untransferred part is extracted and described in the index mail (step 34). On the other hand, if there is no part that is not recorded in the transferred field, the index information is not extracted.

Also, in step 32, when the mail address is an instruction address described in all parts, for example, "user name-index-all @ domain name"
An index information creation command indicating creation of an index mail for the index information of all the stored mails is sent from the mail address determination unit 11-1-4 to the index information processing unit 11-1-5.

In the index information processing section 11-1-5, the electronic mail sent from the mailbox management section 11-1-1 based on the input index information creation command is sent without referring to the transferred field. The index information is extracted and described in the index mail (step 35).

When the index information processing section 11-1-5 confirms that the index information transmission processing has been performed for all the stored mails addressed to the user A (step 30), the index mail is transmitted to the transmission / reception section 11-1.
The data is transmitted to the mail server 11-n of the LAN 10-n via -1-7 and the communication line 40 (step 36). Therefore, the mail server 11-1 of the LAN 10-1
One index mail is returned to the index requester in response to one index transmission request mail transmitted.

Thereafter, the index mail is displayed on the screen in the mail client 12-n of the LAN 10-n that has received the index mail. Among the parts of the index mail displayed on the screen, those that do not require transfer are deleted and returned to the mail server 11-1 of the LAN 10-1. In the present invention, the returned mail is referred to as a transfer request mail.

Next, the operation of the mail transfer process will be described with reference to FIG. When the mail address determination unit 11-1-4 of the mail server 11-1 determines that the mail address of the received electronic mail indicates a mail transfer request (step 17 in FIG. 6),
Mail transfer processing is performed.

Transfer request processing unit 11 receiving an instruction to start mail transfer processing from mail address determination unit 11-1-4
In the step 1-6, the mailbox management unit 11-1-1
It is determined whether or not all of the electronic mails (stored mails) addressed to user A stored in the mailbox 11-1-2 have been subjected to the mail transfer processing via the process (step 50 in FIG. 8).

As a result of the judgment, if there is a stored mail that has not been processed, the stored mail is taken out by the mailbox management section 11-1-1 (step 51).
It is sent to the transfer request processing unit 11-1-6. Next, the mail address determination unit 11-1-4 determines whether the mail address of the transfer request mail is the designated part transfer instruction address (step 52).

As a result of the determination, if the designated part transfer instruction address, for example, “user name-transfer @ domain name”, it indicates to the transfer request processing section 11-1-6 that the transfer of the storage mail specified by the index is instructed. A transfer request command is sent. The transfer request processing unit 11-1-6 determines whether or not the extracted stored mail is included in the index information of the transfer request mail based on the input transfer request command (step 5).
3).

As a result of the determination, if the part is included in the index, the part specified by the index information is extracted from the stored mail and transferred to the mail server 11-n (steps 54 and 55). When the transfer is completed, the transferred part name is recorded in the transferred field of the stored mail (step 56).

If it is determined in step 52 that the mail address of the transfer request mail is not the designated part transfer instruction address, then it is determined whether or not the mail address is an all part transfer instruction address (step 57).

As a result of the judgment, all part transfer instruction addresses,
For example, when “user name-transfer-all @ domain name”, the transfer request processing unit 11-1-6
A transfer request command is sent to all the unsent stored mails to be transferred. Transfer request processing unit 11-1-
In step 6, based on the input transfer request command, it is determined whether the extracted stored mail has not been transferred and has a part corresponding to the transfer condition (step 58). The transfer condition is a condition described in the transfer request mail, and is, for example, a condition specifying a size, a file format, and the like.

As a result of the judgment, the stored mail has not been transferred,
In addition, when there is a part corresponding to the transfer condition, the mail server 1 of the LAN 10-n is transmitted from the transfer request processing unit 11-1-6 via the transmitting / receiving unit 11-1-7 and the communication line 40
The stored mail including the part corresponding to the transfer condition is transferred to 1-n (step 55). And after the transfer is completed,
The transferred part is recorded in the transferred field of the stored mail (step 56).

Therefore, in the mail server 11-1, in response to one transmitted transfer request, the stored mail designated by the index or the untransferred mail corresponding to the transfer condition is transmitted to the transfer requester in mail units. Will be transferred. In step 57, when the mail address of the transfer request mail does not indicate that all unsent stored mails are to be transferred, the mail transfer processing can be ended.

The mail transfer function of the computer (e-mail transfer system, mail server, etc.) in the above embodiment is realized by an e-mail transfer program stored in the mail server. The e-mail transfer program, when read by the computer, sends a command to each component of the computer, and performs predetermined processing, for example, address determination processing of a mail address determination unit, index information extraction of an index information processing unit, and creation of index mail Processing, transfer part extraction processing of the transfer request processing unit, and the like are performed. Thereby, the mail transfer function is realized by an electronic mail transfer system or a mail server in which the electronic mail transfer program and the computer cooperate.

An electronic mail transfer program for realizing the mail transfer function is stored in a computer-readable recording medium, such as an external storage device and a portable recording medium, in addition to being stored in the ROM of the computer. Can be. The external storage device is a memory expansion device that has a built-in storage medium such as a CD-ROM and is externally connected to a mail server. On the other hand, a portable recording medium is a recording medium that can be mounted on a recording medium drive (drive device) and is portable, and includes, for example, a flexible disk, a memory card, and a magneto-optical disk.

Then, the program recorded on the recording medium is loaded into the RAM of the computer and executed by the CPU. By this execution, the function of the mail server of the present embodiment described above is realized. Further, when an electronic mail transfer program is loaded by a computer, the electronic mail transfer program held by another computer can be downloaded to its own RAM or external storage device using a communication line. The downloaded e-mail transfer program is also executed by the CPU to realize the mail transfer function of the mail server of the present embodiment.

[0110]

As described above, according to the present invention, the mail server has a function of transmitting the index information to the mail server of the transfer destination, a transfer function by designating the index,
Since it has an unsent mail transfer function, it is possible to confirm the presence or absence of arriving mail and make a mail transfer request to a mail server to which access from other organizations is restricted by a firewall or the like.

[0111] Since the index mail contains the identification information of the e-mail and the attached file information such as the file name, file format, and size of the attached file as index information, the user who wants to transfer the file can transfer the file. Can efficiently and freely select and delete unnecessary parts and large-sized parts.

Further, by storing a transferred field for recording the transferred part in the mailbox together with the e-mail, the mail server recognizes the part transferred in the past and uses it for extraction of index information and transfer processing. it can. Therefore, for parts that have already been transferred,
Since transfer is not performed again, efficient transfer can be realized.

Also, since the index information transmitted from the transfer source mail server to the transfer destination mail server is deleted as to the part not requested to be transferred, and is then used as it is in the transfer request, the index information to be transferred can be used. For the selection, the e-mail editing function of a general mail client can be used.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an electronic mail transfer system of the present invention.

FIG. 2 is a functional block diagram showing a functional configuration of a mail server in the electronic mail transfer system of the present invention.

FIG. 3 is a diagram showing an image of an electronic mail (stored mail) stored in a mailbox in the electronic mail transfer system of the present invention.

FIG. 4 is a diagram showing index information.

FIG. 5 is a diagram showing an index mail.

FIG. 6 is a flowchart showing processing of an e-mail received in the e-mail transfer system of the present invention.

FIG. 7 is a flowchart showing an operation of index information transmission processing in the electronic mail transfer system of the present invention.

FIG. 8 is a flowchart showing an operation of a mail transfer process in the electronic mail transfer system of the present invention.

[Explanation of symbols]

 1 Electronic Mail Transfer System 10-1, 10-2 to 10-m, 10-n LAN 11-1 to 11-n Mail Server 11-1-1 to 11-n-1 Mailbox Management Unit 11-1-2 To 11-n-2 Mailbox 11-1-3 to 11-n-3 Forwarded field processing unit 11-1-4 to 11-n-4 Mail address judgment unit 11-1-5 to 11-n-5 Index information processing section 11-1-6 to 11-n-6 Transfer request processing section 11-1-7 to 11-n-7 Transmission / reception section 12-1 to 12-n Mail client 13-1 to 13-n Firewall 20 Mobile terminal 30 relay station 40 communication network 50 communication network

Claims (8)

[Claims] 1. An electronic mail transfer method for transferring an electronic mail having a mail text and an attached file from one network to another network, wherein the one network transmits an index mail indicating a list of the electronic mails. The other network receives the index mail, selects an e-mail requesting transfer from the list of e-mails indicated by the received index mail, and sets the selected e-mail as a transfer request. Receiving the transfer request, and transferring the e-mail indicated by the received transfer request to the another network. 2. The method according to claim 2, wherein the mail body and the attached file are each a part, and the one network describes a list of the parts included in each of the stored e-mails in the index mail; The network selects a part requesting transfer from the list of the parts indicated by the received index mail and sets the selected part as the transfer request, and the one network determines the part indicated by the received transfer request as the other part. 2. The electronic mail transfer method according to claim 1, wherein the electronic mail is transferred to a network. 3. The e-mail has a transferred field that records the part that has already been transferred, and the one network is configured to perform, for all of the parts included in each of the stored e-mails, All part description instruction addresses instructing to be described in the index mail, and parts of each of the stored e-mails which are not recorded in the transferred field are described in the index mail. And the other network requests transmission of the index mail to either one of the all part description instruction address or the untransfer part description instruction address. Send index mail transmission request to the one network The one network transmits the index mail based on an instruction of the all part description instruction address or the untransferred part description instruction address which is the destination of the received index mail transmission request. 3. The method according to claim 2, wherein the electronic mail is transmitted to a network. 4. The one-network includes an all-part transfer instruction address for instructing to transfer all of the untransferred parts among the parts of each of the stored e-mails, and the stored e-mail. Of the parts of each of the electronic mails, possesses a designated part transfer instruction address for instructing to transfer the part described in the index mail, and the other network, the all part transfer instruction address or the The transfer request is transmitted to the one network, with one of the designated part transfer instruction addresses as a destination, and the one network transmits the all part transfer instruction address or the designation designated as the destination of the received transfer request. Based on the instruction of the part transfer instruction address, each of the stored e-mails 4. The electronic mail transfer method according to claim 2, wherein the part is taken out from the network and transferred to the other network. 5. The index mail, wherein identification information of the electronic mail included in the part and attached file information such as a file name, a format, and a size of the attached file are described as index information. Item 6. The electronic mail transfer method according to any one of Items 1, 2, 3, and 4. 6. The electronic mail transfer according to claim 1, wherein the transferred field records a mail address to which the part has been transferred, together with the already transferred part. Method. 7. A mail server having a mailbox for storing an electronic mail, an index information processing unit for creating an index mail indicating a list of the electronic mails, and the index created by the index information processing unit. A sending unit that sends an email to another server or a mobile terminal, and at the other server or the mobile terminal, one or more emails selected from the email list indicated by the index email, A receiving unit that receives the transfer request as a transfer request, a transfer request processing unit that extracts the one or more emails indicated by the transfer request from the receiving unit from the mailbox, and transfers the e-mail to the other server or the portable terminal. A mail server comprising: 8. An e-mail transfer program for causing the one network to execute a process of transferring an e-mail having an e-mail text and an attached file from one network to another network, wherein the e-mail list indicates the list of e-mails. Create an index mail, send the created index mail to the other network, and in the other network, select one or two or more e-mails selected from the list of the e-mails indicated by the index mail An e-mail transfer program which receives a transfer request and causes the one network to execute a process of transferring the one or more e-mails indicated by the received transfer request to the other network.