JPH11266279A - Electronic mail management system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To transmit and receive electronic mail by a desk-top or a mobile terminal, while maintaining security strength without being conscious of a fire wall, even from the outside of the fire wall. SOLUTION: A bus mail server 8 provided with an IMAP 4 mail server 13 for ciphering and deciphering the electronic mail and managing the mail state information of the mail is installed inside a fire wall 7 and a remote mail server for transmitting and receiving the electronic mail inside a bus LAN 35, spooling ciphered mail received from the bus mail server and transmitting and receiving the electronic mail from the mobile terminal and the desk-top on the outside of the fire wall through an internet network 1 is installed in the outside of the fire wall. The synchronization of the mail of the bus mail server and the remote mail server is performed through the synchronization of a mail state provided in the mobile terminal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for reading mail from a mail server inside a firewall from outside the firewall without lowering security. In particular, the present invention relates to a mail system that can always operate (read and write) mail in the same mail server environment without the mail user managing the integrity of mail stored in each mail server inside and outside the firewall.

[0002]

2. Description of the Related Art As a method of reading a mail in a main mail server from outside a firewall such as a destination, (1)
A method in which mail delivered to a core mail server is transferred to an Internet network provider and mail is read from a mailbox of the provider from a destination or the like, and (2) a network is entered from an access point of the provider and crosses a firewall to a key network. A method of reading mail directly from a mail server, one having a host table or network table that identifies a host or a predetermined standard for which a firewall needs to encrypt data packets, and (3) a telephone for access within the firewall. There is a method in which a number is provided, a telephone call is made to this number from a place where the user is out of the office, a connection is made to a network, and mail is read from a main mail server via a telephone line.

[0003]

The above prior arts have the following problems. (1) When mail is transferred to the provider and the mail is not left on the main mail server, even if you want to read the mail on a terminal inside the firewall, the mail is sent to the provider.
It is necessary to make a PP connection or connect to an access point for personal computer communication. If mail is also left on the main mail server, centralized management of mailboxes is not possible.
It is necessary to synchronize the mailbox of the backbone mail server with the mailbox of the provider. Here, the synchronization processing refers to centralized management so that the contents of mailboxes of two or more servers are the same. (2) In a mode of accessing from the Internet network, communication is performed through a firewall, so that even if a packet is encrypted, security strength is reduced. Also,
Since the login name and password of the user and the text of the mail are dropped on the Internet network to access the backbone mail server, the confidentiality information may be stolen. (3) In a mode in which an access server is installed in a firewall, mail is fetched using a telephone line, so that telephone charges are high in a long distance.

The present invention has been made in order to solve the above-described problems. In the present invention, a main mail server is installed inside a firewall, a remote mail server is installed outside the firewall, and mail is sent to a mailbox of the mail server. , And the unique ID assigned by the ID acquisition means is used as the identification number of the mail, and the mail arriving at the main mail server is transmitted to the remote mail server. The object of the present invention is to solve the above-mentioned problems (1) and (3) by realizing synchronization of mail in the mailbox of the remote mail server with the remote mail server and connecting to the remote mail server from the Internet network.

Further, a main mail server is installed inside the firewall, a remote mail server is installed outside the firewall, a copy of the mail from the main mail server to the remote mail server is encrypted, and then the mail is transmitted. The synchronization of the e-mail is also performed when the latest e-mail status information of the e-mail is sent by e-mail or when the latest e-mail status of the mobile terminal is connected to the e-mail server, so that there is no direct communication across the firewall. In addition, when sending mail to the remote mail server, the mail status information and the body of the mail are encrypted with the key code of each user, and the mail is saved in the remote mail server's mailbox in an encrypted state, and the mail is saved. When reading, decrypt it with your key code on the mail client side and read it. As described above, even when reading mail from outside the firewall, the mail server inside the firewall is not accessed at all, so that there is no need to consider access security inside the firewall. An object of the present invention is to solve the above problem (2) using the above means.

[0006]

An electronic mail management system according to a first aspect of the present invention comprises an identification means for identifying a mail between different mail servers, a mail header, presence / absence of encryption, and unread / read mail. Storage means for storing the mail status information of the updated date and time of the mail, updating means for updating the stored mail status information to the latest one, and obtaining consistency of the mail based on the updated new mail status information. Synchronization means for synchronizing mail between mail servers, encryption / decryption means for only a specific user to decrypt the text of a mail encrypted by a specific user, and mail status information and encryption of the latest mail by an update means Synchronization means for synchronizing the body of the mail by sending the body of the mail encrypted by the decryption means to the remote mail server A connected main mail server, and a remote mail server having a comparative search means and connected outside the firewall, wherein the comparative search means converts a unique ID assigned by the remote mail server to a unique ID assigned by the main mail server. It is configured to read the mail in the main mail server corresponding to the mail in the remote mail server by acquiring and reading the mail in the remote mail server outside the firewall via the Internet network. An e-mail management system with means is provided.

In the electronic mail management system according to a second aspect of the present invention, the backbone mail server includes encryption / decryption means for performing encryption / decryption using a key centrally managed by the backbone mail server when transmitting / receiving from outside the firewall. Is done.

[0008] In the electronic mail management system according to a third aspect of the present invention, the remote mail server is configured to include storage means for storing only the encrypted mail.

In the electronic mail management system according to a fourth aspect of the present invention, the core mail server is provided with a synchronizing means for synchronizing the mail by automatically updating the mail status information of the mail when connecting to the mail server. It is composed of

[0010] In the electronic mail management system according to a fifth aspect of the present invention, each of the main mail server and the remote mail server is provided with ID acquisition means for assigning a unique ID to each mail as an identifier in each identification means.

[0011] In the electronic mail management system of the sixth invention, the remote mail server supports IMAP4 or an equivalent protocol, has storage means for always storing mail, and updates the mail status information of the mail of the main mail server. It is configured to synchronize the mail between the main mail server and the main mail server just by doing.

[0012] In the electronic mail management system according to a seventh aspect of the present invention, the core mail server only transmits the latest mail status information to the remote mail server by mail, and any terminal can transmit and receive mail in the latest mail status environment. It is configured to have a possible synchronization means.

[0013] In the electronic mail management system of the eighth invention, the mobile terminal includes synchronization means for performing synchronization by updating the mail status information of the main mail server to the latest mail status information of the mail stored in the mobile terminal. It is configured as follows.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a block diagram showing a schematic configuration example of an electronic mail management system of the present invention. In FIG. 1, 1 is an Internet network, 2 is a telephone line, 3 is an access point, 4 is a router, 5 is a remote mail server, 6 is a mail gateway, 7 is a firewall, 9 is a desktop, 8 is a core mail server, and 10 is a core mail server. A mobile terminal, 11 is a LAN card, 12 is a modem, 22 is storage means, and 35 is a main LAN. In the remote mail server 5, 22 is a storage means for storing only encrypted mail, 23 is an IMAP4 mail server, and 24 is a unique ID assigned by the main mail server 8 from a unique ID assigned by the remote mail server. Means for comparing and searching, 25 means for identifying, 2
6 is a mapping database.

In the remote mail server 5, the IMA
The P4 mail server 23 supports SMTP and IMAP4, and performs mapping between the unique ID assigned by the IMAP4 mail server 13 of the core mail server 8 and the unique ID assigned by the IMAP4 mail server 23 of the remote mail server 5.

As shown in FIG. 1, a basic mail server 8 is installed on a main LAN 35 in a firewall 7 and a remote mail server 5 is provided.
Is installed outside the firewall 7 and connected to the Internet 1 via the router 4. The desktop 9 is connected to the main LAN 35 and has an IMAP4 mail client 32. Mobile terminal 10 is IMAP
It has a four mail client 27. Mobile terminal 10
May be connected to the main LAN 35 via the LAN card 11 or may be connected to the Internet 1 via the telephone line 2 and the access point 3.

In such a configuration, the desktop 9 communicates with the IMAP in the main mail server 8 via the main LAN 35.
4 can receive the mail stored in the mail server 13, and the mobile terminal 10 can use the IMA in the main mail server 8 via the main LAN 35 like the desktop 9.
The mail stored in the P4 mail server 13 can be received. On the other hand, the mobile terminal 10 has a modem 12,
The user can enter the Internet network 1 via the telephone line 2 and the access point 3 and receive mail stored in the IMAP4 mail server 23 in the remote mail server 5 via the router 4.

FIG. 2 is a diagram showing details of the main mail server 8. In FIG. 2, 13 is an IMAP4 mail server, 14 is a polling server, 15 is a synchronizing means for synchronizing mails between mail servers by taking consistency of mails based on updated new mail status information, and 16 is a unique means. Identification means for identifying an email using an ID, 1
7 is I for which the unique ID number is acquired from the mail acquisition time
D acquisition means, 18 is update means, 19 is storage means for storing mail status information of a mail header and the presence or absence of encryption, unread / read mail, and update date and time of mail, 20 is mail body synchronization means, 21 is mail body This is an encryption / decryption means by which only a specific user can decrypt the text of a mail encrypted by a specific user.

In FIG. 2, the main mail server 8 is
It supports MTP and IMAP4, manages mail status information by the synchronization means 15, and obtains an IMAP4 mail server 13 responding to requests from the IMAP4 mail client 27 of the desktop 9 and the mobile terminal 10, and a new mail in the IMAP4 mailbox. It has a polling server 14 that performs polling and mail decryption. The mail transmission / reception protocol of the backbone mail server 8 may be an equivalent protocol other than SMTP and IMAP4.

FIG. 3 is a flowchart showing the operation of the main mail server. In step 201, the polling server 14 checks at regular intervals or
When the mail reaches the MAP4 mail server 13, the mail is acquired from the IMAP4 mail server 13. Next, in step 202, the identification unit 16 and the ID acquisition unit 17 identify the mail. Here, ID acquisition means 1
Reference numeral 7 denotes a unit for acquiring a unique ID number from the mail acquisition time. An IMAP4 compatible mail server automatically provides this unique ID.
D may be used. The identification means 16 uses this unique ID
Use to identify the email.

In step 203, it is determined whether or not the mail obtained from the polling server 14 is a new mail.
In the case of a new mail, in step 204, the body of the mail is encrypted by the encryption / decryption means 21, and in step 205, the unique ID obtained by the ID acquisition means is added to the header of the mail.
The mail is transmitted to the remote mail server 5 by SMTP. By immediately transferring the new mail obtained by the polling server 14 to the remote mail server by SMTP, the consistency of the mail body between the main mail server and the remote mail server, that is, synchronization is maintained. This is referred to as mail body synchronization means. If the mail obtained from the polling server is not new, in step 207, the mail status information is updated by the updating means 18 and step 208
, The storage means 19 stores the mail status information. If the mail status information matches the existing mail status information stored by the storage means 19, the consistency is maintained and there is no need to update. When the stored existing mail status information is prioritized, the updating means 19 sends the IM
A command is sent to the AP4 mail server 13 and the IMAP4
The mail status information stored in the mail server 13 is changed. At this time, the existing mail stored in the storage unit 19 and the mail stored in the IMAP4 mail server 13 are identified by the identification unit 16.

FIG. 4 is a flowchart showing the operation of the remote mail server 5. In FIG.
In step 301, a mail is obtained from an IMAP4 mail server in response to a request from a mail client. However, even with the same mail, the unique ID given by the IMAP4 mail server 13 of the main mail server
And IMAP4 mail server 23 of remote mail server
Of course is different. Therefore, in step 302, the comparison search means 24 acquires the unique ID assigned by the main mail server 8 from the unique ID assigned by the remote mail server. That is, the mail of the mobile terminal 10 and the mail of the remote mail server 5 are identified with the unique ID assigned by the main mail server 8. Comparison search means 24
If the unique ID assigned by the main mail server 8 cannot be obtained in step 3, the unique ID is not registered in the mapping database, and the mail becomes a new mail.
The unique ID assigned by the main mail server is obtained from the header of the mail, and in step 304, it is registered in the mapping database. If it is a new mail, in steps 306 and 307, the same processing as the mail synchronization means of the main mail server is performed.

FIG. 5 is a diagram showing details of the mobile terminal 10. In FIG. 5, 27 is an IMAP4 mail client, 28 is encryption / decryption means, 29 is synchronization means for performing synchronization by updating the mail status information of the main mail server to the latest mail status information of the mail stored in the mobile terminal, Numeral 30 denotes identification means for identifying a mail using a unique ID, and numeral 31 denotes a storage means for storing mail status information.

In the mobile terminal 10, IMAP4
The mail client 27 supports SMTP and IMAP4. The encryption / decryption means 28 encrypts the body of the mail with the key code of the sending user, transmits the mail, decrypts the mail with the key code from the mailbox of the remote mail server 5, and takes in the mail. The synchronization means 29 manages the unique ID, the header of the mail, the presence / absence of encryption, and the mail status information of unread / read mail and deletion of the mail.

Here, for example, when the user A of the mobile terminal 10 sends a mail to the user B of another server, the body of the mail is encrypted with the key code of the user A, the destination is also the user A, and the mail gateway 6 To send the mail to the main mail server 8. However, the header of the mail indicates that the original destination is the user B. For example, a user B address or the like is added after the subject of the mail header. When the mail arrives at the IMAP4 mail server 23 via the mail gateway 6, the main mail server 8 enters a mail spool (not shown) of the IMAP4 mail server 23. The polling server 14 acquires the newly arrived mail that has arrived at the mail spool of the IMAP 4, acquires the key code of the destination user User A from the synchronizing means 15, and performs decryption with the key code.

Next, the unique ID assigned to the mail by the ID acquisition means 17 is added to the mail header,
The unique ID, the header of the mail, the presence / absence of encryption, and the mail status information of the unread / read mail and the deletion of the mail are registered in the synchronization unit 15, and the key code of the original destination user B is acquired from the synchronization unit 15, The mail body is encrypted with the key code, and the IMAP4 mail server 1 transmits the mail body to the remote mail server 5. Then, before going out, the user B stores the mail status of his / her mailbox and the shared mailbox and his / her own key code in the synchronization unit 29 of the mobile terminal 10 from the synchronization unit 15 of the main mail server, and communicates with the remote mail server 5. Synchronize mailboxes when accessing.

To take in the mail from the remote mail server 5 in the desktop 9 and the mobile terminal 10, the key code is acquired from the synchronizing means 29, the key code is decrypted and read, and the mail is edited.
The update information of the mail status accompanying the registration is registered in the synchronization means 29, and upon returning from the outside, it is connected to the main LAN 35, and the mail state is synchronized between the synchronization means 15 of the main mail server 8 and the synchronization means 29 of the mobile terminal 10. Execute

FIG. 6 shows a configuration example of registered user information and mail status information handled by the synchronization means. In FIG. 6, for example, the user information 301 registers a login name, a password, a directory name and its unique ID. The mail information 302 includes a directory name and its unique ID.
(UID), mail unread / read, mail deletion status, encryption status, update date and time, and mail status information such as the header of the mail are registered.

FIG. 7 is a detailed flowchart showing an example of the operation of the mail acquisition means and the mail transfer means of the polling server 14. FIG. 8 is a flowchart showing an example of a polling server for notifying the arrival of new mail from the SMTP proxy server. FIG. 9 is a flowchart showing the mail synchronization process at the time of polling. The detailed operation of the polling server 14 will be described below with reference to FIGS.

In step 401 of FIG. 7, the polling server 14 is started. The polling server 14 may be a daemon server that starts at regular intervals, as shown in step 402, and may be steps 501 to 505 shown in FIG.
In the above, an SMTP proxy server or the like may be prepared, and when a new mail arrives at the SMTP proxy server, a command may be given to the polling server to activate the mail. Also, a unique ID assigned by the IMAP4 mail server may be adopted as the ID acquisition means,
When a new mail arrives at the TP proxy server, a unique ID may be uniquely assigned. As a means for identifying a mail, there is a method of adding a unique ID obtained by the ID acquiring means 17 to a mail header. For example, "Su
bject: message # $ 00023156782 $ # ”and adding a unique ID enclosed by“ # ”at the end of the subject of the mail header.

First, in FIG. 7, the polling server 1
4 obtains the login names and passwords of all the users registered in the main mail server from the synchronization means in step 403. In step 404, the user logs in to the IMAP4 mail server with the login name and password of the user. In step 405, the header, mail status information, and unique ID of the new mail to the user can be obtained. Is added to the unique ID. Step 407
, The acquired mail status information, its date and unique ID are registered in the synchronization means. Next, in step 408, if the mail text has already been encrypted, in step 409, the key code of the destination user is obtained from the synchronization means, and in step 410, the mail text is decrypted. Here, an identification key indicating whether or not the data is encrypted is added to the header information. For example, add an identification key to the subject of the mail header. In step 411, it is checked whether an original destination user is specified in addition to the destination user.

As a method of designating the original destination user, for example, the original destination user is added to the subject of the mail header. If the original destination user has been specified in step 412 and the original destination user has been registered in the synchronization means, in step 413, the mail body is encrypted with the key code of the original destination user. If the message is transmitted to the remote mail server 5 by SMTP to the original destination user and is not registered in the synchronization means, encryption cannot be performed.
, The original text is transmitted to the original destination user by SMTP. If the original destination user is not specified in step 416 and the destination user is registered in the synchronization means, the mail body is encrypted with the key code of the destination user in step 417, and the remote mail server is If the message is not sent to the destination user and is not registered in the synchronization means, encryption is not possible. In step 415, the original text is sent to the destination user by SMTP. Next, in step 419, a mail synchronization process is performed on the mail. In step 420, this process is performed for all newly arrived mails. In step 421, this process is performed for all registered users.

FIG. 8 is a diagram showing an example in which an SMTP proxy server for temporarily receiving mail in place of the SMTP server is provided. In step 502, when there is an event that a new mail has arrived at the SMTP proxy server, the polling server 14 is activated. When the unique ID assigned by the IMAP4 mail server is not used for the ID acquisition means 17, when a new mail arrives at the SMTP proxy server, the ID acquisition means for assigning a unique ID to the mail is performed, and the mail status information of the mail is obtained. They may be stored and mailed to a remote mail server. In FIG. 8, the other steps are almost the same as those in FIG. 7, and the description is omitted.

The mail synchronizing process shown in FIG.
It is a figure which shows the detailed flowchart of step 419 and step 523 in a middle. In FIG. 9, step 60
In step 2, if the request for synchronizing the mail status information is described in the header of the mail, in step 603, the mail status information written in the body of the mail is analyzed.
In step 604, it is checked from the update date / time information whether the mail status information is newer than the mail status information held by the main mail server. If the state sent by e-mail is newer, the mail state information of the sending user possessed by the main mail server is updated in step 605, and the synchronization processing ends in step 606. The updating method will be described below with reference to FIG.

FIG. 10 is a flow chart showing an example of the operation of the mail status update process in the process of synchronizing the mail between the mail server and the mobile terminal. This synchronization means, for example, when connecting the main LAN and the mobile terminal,
The mail status information obtained from the synchronization means on the mail server side
By copying the mail status information obtained from the synchronization means on the mobile terminal side to the mobile terminal side and copying it to the mail server side and taking update means on each side, the synchronization means on the mail server also becomes the synchronization means on the mobile terminal A method that can have exactly the same mail status information, or that the mail status information obtained from the synchronization means on the mobile terminal side is copied to the mail server side and the mail server side performs the update means only, and the updated mail status information Is provided to the mobile terminal side so that the two synchronization means can have exactly the same mail status information.

In FIG. 10, first, in step 703, the mail status is updated by two pieces of mail status information,
That is, the state of the directory in the information of the user of the mail user who has transmitted / received the mail with the mobile terminal is compared with the state of the directory owned by the information of the user of the mail server. If there is a difference in the state of a certain directory in step 704, the old state is rewritten to the latest update date and time in step 705. Next, in step 706, the mail status in the directory is compared. Step 707
In step 708, if there is a difference between certain mail states, the old state is rewritten to the latest update date and time. In steps 709 and 710, this update is performed on all directories and all mails owned by the user. Here, when updating, the update date and time are used as keys, but anything may be used as long as it is clear which state is the latest one. In step 711, the update processing ends.

FIG. 11 shows the IM of the remote mail server 5.
A proxy server of a remote mail server having a comparative search means for mapping an ID assigned by the AP4 mail server 23 or an ID acquisition means using an equivalent protocol and a unique ID of a new mail sent from the main mail server 8. It is a flowchart showing the operation.

FIG. 12 is a block diagram showing the structure of the mapping data. If the ID acquisition unit that assigns a unique ID is used instead of the ID acquisition unit that uses the ID assigned from the IMAP4 mail server, this comparison unit is required not only for the remote mail server but also for the core mail server. .

In FIG. 11, in step 801, the proxy server of the remote mail server 5 that has started the proxy waits for a log-in request from the mail client to the mail server in step 802. When the user logs in to the mail server with the login name and the password and the new mail arrives, in step 804, the remote mail server acquires the ID and header assigned to the mail. Since the mail arriving at the remote mail server is a mail sent from the main mail server, the unique ID assigned by the main mail server is described in the header of the mail. For example, a unique ID is added to the subject. In step 805, the unique ID is obtained from the header.

Next, in step 806, the unique ID and the ID assigned by the ID acquisition means of the remote mail server are registered in the mapping database, and in step 807, the mail client is notified that there is a new mail. Further, in step 808, when there is a mail acquisition request from the mail client by designating the unique ID, in step 809, the ID assigned by the remote mail server to the unique ID from the mapping database is acquired, and in step 810, the ID is obtained. Get mail from the remote mail server using
When sending the mail to the SP mail client, the mail is converted into a unique ID again and then sent.

[0041]

The electronic mail management system according to the first aspect of the present invention provides an identification means for identifying a mail between different mail servers, a mail header, presence / absence of encryption, unread / read mail and update of the mail. A storage unit for storing date and time mail status information, an updating unit for updating the stored mail status information to the latest one, and a mail server for obtaining consistency of mail based on the updated new mail status information. Synchronization means for synchronizing mail, encryption / decryption means capable of decrypting only the text of a mail encrypted by a specific user by a specific user, and mail status information and encryption / decryption means of the latest mail by an updating means Synchronization means for synchronizing the main body of the mail by sending the body of the encrypted mail to the remote mail server. A mail server and a remote mail server having a comparison search means and connected outside the firewall, wherein the comparison search means obtains a unique ID assigned by the main mail server from a unique ID assigned by the remote mail server, and By reading the mail in the remote mail server outside the firewall via the network, it is configured to read the mail in the main mail server corresponding to the mail in the remote mail server. By installing and synchronizing them, mail inside the firewall can be read from outside the firewall.

In the electronic mail management system according to the second aspect of the present invention, the key mail server transmits and receives data from outside the firewall using a key centrally managed by the key mail server.
Since it is configured to have encryption / decryption means for decrypting, outgoing mail is encrypted and decrypted by the proxy server, and the mail server outside the firewall encrypts the mail so that only the destination user can decrypt it and sends it. Then, the encrypted mail is stored, and the mail can be sent and received safely even with Internet network mail.

Since the remote mail server of the electronic mail management system according to the third invention is provided with storage means for storing only the encrypted mail, the mail can be transmitted and received safely even with Internet network mail.

[0044] In the electronic mail management system of the fourth invention, the core mail server is provided with synchronization means for synchronizing the mail by automatically updating the mail status information of the mail when connecting to the mail server. Therefore, mail can be sent and received without the mail client being aware of the consistency of mail with the mail server.

In the electronic mail management system according to the fifth invention, the main mail server and the remote mail server are configured so that each identification means includes ID acquisition means for assigning a unique ID to each mail as an identifier. A unique ID is assigned to each mail, which has the effect of facilitating identification and comparison search of the mail during synchronization.

In the electronic mail management system according to the sixth invention, the remote mail server supports IMAP4 or an equivalent protocol, has storage means for always storing mail, and updates the mail status information of the mail of the main mail server. It is configured to synchronize the mail between the main mail server and the main mail server by simply performing the operation, so that the mail client can transmit and receive the mail without being conscious of the consistency of the mail with the mail server.

In the electronic mail management system according to the seventh aspect of the present invention, the main mail server only transmits the latest mail state information to the remote mail server by mail, and any terminal can transmit and receive mail in the latest mail state environment. It is configured to have a possible synchronization means.

[0048] In the electronic mail management system of the eighth invention, the mobile terminal includes synchronization means for performing synchronization by updating the mail status information of the main mail server to the latest mail status information of the mail stored in the mobile terminal. With this configuration, the mobile terminal having the mail status information of the mail is used to synchronize the mail of the mail server inside and outside the firewall, thereby enabling synchronization without creating a tunnel in the firewall.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a schematic configuration example of an electronic mail management system according to an embodiment of the present invention.

FIG. 2 is a diagram showing details of a main mail server of the electronic mail management system according to the embodiment of the present invention.

FIG. 3 is a flowchart showing the operation of the core mail server.

FIG. 4 is a flowchart showing an operation of the remote mail server.

FIG. 5 is a diagram showing details of a mobile terminal.

FIG. 6 is a diagram showing a configuration example of registered user information and mail status information handled by a synchronization unit.

FIG. 7 is a flowchart illustrating an example of a synchronization process of a polling server started at regular time intervals.

FIG. 8 is a flowchart showing an example of the operation of the polling server started by the SMTP proxy server that notifies the arrival of new mail.

FIG. 9 is a flowchart showing a mail synchronization process at the time of polling.

FIG. 10 is a flowchart showing an example of the operation of the mail state updating means during the mail synchronization processing between the mail server and the mobile terminal.

FIG. 11 is a flowchart showing the operation of the proxy server of the remote mail server having the comparison search means.

FIG. 12 is a block diagram illustrating a configuration of mapping data.

[Explanation of symbols]

1. Internet network, 2. Phone line, 3. Access point, 4. Router, 5. Remote mail server, 6.
Mail gateway, 7 Firewall, 9 Desktop, 8 Core mail server, 10 Mobile terminal, 11 LAN card, 12 Modem, 16 Identification unit, 17 ID acquisition unit, 18 Update unit, 19 Storage Means, 20: Synchronization means of mail body, 21: Encryption / decryption means, 22: Storage means, 23: IMAP4 mail server, 24: Comparison search means, 25: Identification means, 26: Mapping database, 32: IMAP4 mail client, 35 ... Basic LAN

Claims (8)

[Claims] 1. An identification means for identifying a mail between different mail servers, and a storage means for storing mail status information of a mail header, presence / absence of encryption, unread / read mail, and updated date and time of the mail. Updating means for updating the stored mail status information to the latest one; synchronizing means for synchronizing the mail between the mail servers by taking the consistency of the mail based on the updated new mail status information; An encryption / decryption unit that allows only a specific user to decrypt the body of the mail encrypted by the user, the latest mail status information of the mail by the updating unit, and the body of the mail encrypted by the encryption / decryption unit to the remote mail server. A main mail server connected to the inside of the firewall having synchronization means for synchronizing the main body of the mail by sending mail, A remote mail server connected to the outside of the firewall, wherein the comparing and searching means acquires a unique ID assigned by the main mail server from the unique ID assigned by the remote mail server, and is located outside the firewall via the Internet network. An e-mail management system, wherein by reading mail in a remote mail server, the mail in the main mail server corresponding to the mail in the remote mail server is read. 2. The electronic mail management system according to claim 1, wherein the backbone mail server includes an encryption / decryption unit that performs encryption / decryption using a key centrally managed by the backbone mail server during transmission / reception from outside the firewall. An e-mail management system, characterized in that: 3. The electronic mail management system according to claim 2, wherein said remote mail server includes a storage unit for storing only encrypted mail. 4. The electronic mail management system according to claim 1, wherein the main mail server is connected to a mail server.
An e-mail management system comprising a synchronizing means for synchronizing an e-mail by automatically updating e-mail status information of an e-mail. 5. The electronic mail management system according to claim 1, wherein the backbone mail server and the remote mail server are:
An electronic mail management system, characterized in that each identification means includes ID acquisition means for assigning a unique ID to each mail as an identifier. 6. The electronic mail management system according to claim 1, wherein the remote mail server supports IMAP4 or an equivalent protocol, includes storage means for always storing the mail, and the mail status of the mail of the main mail server. An e-mail management system that synchronizes mail between a main mail server and a main mail server by simply updating information. 7. The electronic mail management system according to claim 6, wherein the main mail server only sends the latest mail status information to the remote mail server by mail, and the mail is sent to any terminal in the latest mail status environment. An e-mail management system comprising a synchronization unit capable of transmitting and receiving data. 8. The e-mail management system according to claim 6, wherein the mobile terminal performs synchronization by updating the mail status information of the main mail server to the latest mail status information of the mail stored in the mobile terminal. E-mail management system characterized by comprising means.