WO2000065456A1

WO2000065456A1 - E-mail system, e-mail transmission/reception system, and recording medium

Info

Publication number: WO2000065456A1
Application number: PCT/JP1999/006351
Authority: WO
Inventors: Gang Cao; Jianchuen Chen; Wei Wu; Tong Ren; Pong Zhang
Original assignee: Outserv Co., Ltd.
Priority date: 1999-04-26
Filing date: 1999-11-15
Publication date: 2000-11-02
Also published as: AU1180000A

Abstract

A client network (1) includes a communication section (53) for communicating electronic data passable through a firewall (3), and a virtual mail transmission server (51) that transfers e-mail from a mail program (11) to a Web server (6). A mail server network (2) includes a section (71) to send e-mail to a mail server (4). The mail server network (2) includes a section (72) for retrieving the e-mail stored in the mail server (4) and a section (73) for returning the retrieved e-mail to the client network (1). The client network (1) includes a buffer (57) for storing e-mail and a virtual mail reception server (52) for returning the stored e-mail to the mail program (11).

Description

CT / JP99 / 06351 Description

Electronic mail system, electronic data transmission / reception system and recording medium

The present invention relates to a mail comprising a client network provided with a firewall, an information server capable of transmitting and receiving electronic data capable of passing through the firewall of the client network, and a mail server capable of transmitting and receiving electronic mail. In an e-mail system that sends and receives e-mails to and from a server network, even if a firewall is installed in the client network, e-mails can be sent and received easily and safely using general-purpose e-mail software. This is related to an e-mail system that can perform the following.

In addition to the above-mentioned electronic mail transmission and reception, an electronic data transmission and reception system for transmitting and receiving electronic data between a client network and a super network having an authentication server for performing predetermined authentication is provided. It also relates to an electronic data system that can securely perform authentication to an authentication server. Background art

When a client network such as an in-house LAN connects to a wide-area network such as the Internet, it is necessary to establish a connection between the network outside the organization to prevent illegal access from networks outside the organization. Fire rules are often provided. This firewall monitors communication requests inside and outside the organization, and passes or restricts the communication requests as appropriate, thereby providing necessary information to users and ensuring the security of the client network. is there. Here, a predetermined protocol such as SMTP (Simple Mail Transfer Protocol) and POP (Post Office Protocol) is used when sending and receiving e-mail between networks, particularly, on the Internet. Depending on the client network, firewalls may restrict communication using these protocols to ensure the security of the client network. E-mail cannot be sent or received from these client networks via these protocols. That is, mail cannot be sent and received using general-purpose e-mail software that uses these protocols.

In such a case, in order to send and receive e-mail, an e-mail system using a protocol that can generally pass through a firewall, for example, HTTP (Hyper Text Transfer Protocol) (hereinafter referred to as an HTTP mail system) Has been conventionally used. The following briefly describes this HTTP mail system.

Fig. 17 is an overall configuration diagram of a conventional HTTP mail system. As shown in this figure, a client network 101 provided in an organization such as an in-house LAN is connected to a mail server network 102 via an Internet network, and an external network is connected to the client network 101. The above-mentioned firewall 103 is installed between the Internet and the Internet. An e-mail server 104 is installed in the mail server network 102. In order to enable transmission and reception of e-mail to and from the e-mail server 104, computers on the client network 101 use HTTP protocol. Web browser 105 that can communicate with the server is started.

On the other hand, the mail server network 102 is provided with a web server 106 that publishes information using the HTTP protocol, and a program 107 that is started by accessing the web server 106. .

Send and receive e-mail within the client network 101 The user (hereinafter referred to as the user) sends the address (the address on the web server 106 on the mail server network 102) on the web browser 105 started on the client network. specify. The web browser 105 accesses the web server 106, and the web server 106 returns a page for sending and receiving e-mail. Then, a page for transmitting and receiving the e-mail is displayed on the web browser 105.

The page displayed on the web browser 105 is provided with a button or the like for instructing transmission or reception of an e-mail, and can transmit an e-mail transmission / reception instruction to the web server 106.

For example, when an instruction to receive an e-mail is issued, the Web server 106 receiving the instruction activates the program 107, and the program 107 is stored in the mail server 104 of the mail server network 102. Get emails that are. Then, the e-mail is returned to the Web browser 105 of the client network 101 via the Web server 106, and the e-mail can be browsed on the Web browser 105.

When an instruction to send an e-mail is given, the program 107 is similarly activated, and the program 107 sends an e-mail transmitted from the Web browser 105 of the client network 101 to the mail server 104. By doing so, an e-mail can be sent.

In this way, through the Web browser 105 and the Web server, the user can send and receive e-mail even from within the client network 101 where the firewall 103 is installed. Become.

However, when sending and receiving e-mails using the HTTP mail system described above, it is necessary to send and receive e-mails via a Web browser for displaying Web pages. It is difficult to provide GU I (Graphical User Interface) to users. There was also a problem that it was difficult to use.

In addition, when sending and receiving e-mail using the conventional HTTP mail system, it is necessary to communicate not only with sending and receiving e-mail, but also with updating the screen of the Web browser, etc., with the Web server of the mail server network. Therefore, there is a problem that it takes a waste of time from when a user performs an operation to when the process is completed.

Furthermore, in order to obtain the new e-mail, the user needs to make a request to receive the e-mail on the Web browser, so there is a problem that the new e-mail is not obtained until this instruction is given. Was.

In addition, in the conventional general e-mail system, the authentication required for the e-mail server when receiving e-mail was not required when e-mail was sent. Then there was the problem.

Also, for example, when authentication is required for the mail server as described above, it is necessary to request authentication from the client network to an authentication server such as the mail server. The authentication information for the authentication server may frequently flow on the Internet, and the security of sending and receiving electronic data has not been sufficiently ensured. Disclosure of the invention

The present invention has been made in view of such conventional problems. Even when a firewall is installed in a client network, general-purpose e-mail software can easily and safely transmit e-mail. The purpose is to provide an e-mail system that can send and receive.

Further, the present invention provides an electronic data communication system for transmitting and receiving electronic data between a client network and a server network having an authentication server for performing predetermined authentication. The purpose of the present invention is to provide an electronic data system that can securely transmit and receive electronic data, especially authentication to an authentication server, in an evening transmission / reception system.

In order to solve such a problem in the conventional e-mail system, the present invention according to claim 1 provides a client network in which a firewall is installed and a firewall which can pass through the client network. An e-mail system for transmitting / receiving e-mail to / from a mail server network comprising an information server capable of transmitting / receiving electronic data and a mail server capable of transmitting / receiving electronic mail. Communication means capable of communicating electronic data that can pass through the firewall with an information server of the mail server network; and receiving the electronic mail when the electronic mail is transmitted from within the client network. At the same time, the e-mail is sent to the e-mail via the communication means. A virtual sending mail server for sending to the information server of the mail server network, and mail sending means for sending the e-mail sent to the information server to the mail server in the mail server network. The feature is constituted.

The present invention described in claim 2 is characterized in that the communication means of the client network according to claim 1 includes encryption means for encrypting electronic data to be transmitted, and the mail server network In addition, a decryption means for decrypting the electronic data encrypted by the encryption means of the communication means of the client network is provided.

Further, according to the present invention described in claim 3, the communication means of the client network according to claim 1 or 2 can transmit authentication information to a receiving mail server in a mail server of the mail server network. And to the receiving mail server of the mail server based on the authentication information transmitted by the communication means of the client network. An authentication means for requesting authentication is provided.

Further, the present invention according to claim 4 is a communication means capable of communicating an electronic device that can pass through a firewall with an information server of a mail server network, and a mail server of the mail server network. Request means for requesting the e-mail stored in the server; and, in the mail server network, e-mail obtaining means for obtaining the e-mail stored in the mail server; Replying means for returning the electronic mail acquired by the mail acquiring means to the communication means of the client network via the information server; and further comprising: a reply means of the mail server network to the client network. Returned to the above communication means Mail holding means for holding a child mail, and a virtual reception mail server for replying to the mail held by the mail holding means when an e-mail reception request is received from within the client network. It is characterized by that.

Further, the present invention according to claim 5 is characterized in that the mail server network according to claim 4 further comprises encryption means for encrypting electronic data returned by the reply means, and The communication means is provided with a decryption means for decrypting the electronic data encrypted by the encryption means of the mail server network.

The present invention described in claim 6 is characterized in that the request means of the client network according to claim 4 or 5 requests the e-mail at a predetermined time interval. Be composed.

Further, according to the present invention, there is provided an electronic data transmitting / receiving apparatus for transmitting / receiving electronic data between a client network and a server network provided with an authentication server for performing predetermined authentication for access from the client network. An evening transmission / reception system, wherein the client network is connected to the server network Communication means capable of communicating authentication information to the server authentication server with the server network. The authentication server transmits the authentication server to the server network based on authentication information transmitted by the communication means of the client network. An authentication means for requesting authentication of the authentication information, and an identifier for the authentication information when the authentication by the authentication means is successful, and transmitting the identifier to the communication means of the client network. And a communication means for the client network, wherein the communication means of the client network adds the identifier given by the identifier giving means of the server network to transmit electronic data, and the authentication means for the server network. Is to determine whether the identifier added to the electronic data is valid or not. Ri configured as characterized by performing the authentication. Also, the present invention according to claim 8 is characterized in that the server network identifier assigning means of the present invention according to claim 7 comprises the identifier assigned during a series of data communication with the client network communication means. Is changed.

The present invention according to claims 9 to 11 relates to a computer-readable recording medium. According to the present invention, in a case where an e-mail is transmitted from within a client network, the step of receiving the e-mail within the client network; and an e-mail capable of passing the received e-mail through a firewall. Transmitting the data to the information server of the mail server network as data and sending the e-mail transmitted to the information server of the mail server network to the mail server of the mail server network; An e-mail transmission / reception program to be executed by a computer is recorded on a computer-readable recording medium.

The present invention according to claim 10 is a step of obtaining electronic mail stored in a mail server of the mail server network in a mail server network. A step of returning the obtained e-mail to the client network via the information server; a step of holding the e-mail returned from the mail server network in the client network; A step of sending back the stored e-mail when an e-mail reception request is received from within the e-mail, and recording an e-mail transmission / reception program for causing a computer to execute the e-mail transmission / reception program on a computer-readable recording medium. Is configured as

The present invention according to claim 11 further includes a step of transmitting authentication information from a client network to an authentication server of a server network, and authenticating the authentication server of the server network based on the transmitted authentication information. Requesting the authentication server, providing an identifier for the authentication information when the authentication to the authentication server is successful, transmitting the identifier to the client network, and adding the identifier from the client network. Transmitting the electronic data to the computer, and performing the authentication by determining whether or not the identifier added to the electronic data is valid in the server network. Let's send and receive electronic data And it is configured as a feature that you recorded in computer-readable recording medium.

Further, according to the present invention as set forth in claims 12 to 15, a firewall including a mail server is installed in a mail server network, and the information server is provided outside the firewall. It is about the case. According to the present invention as set forth in claim 12, the electronic data transmitted to the information server via the communication means of the client network is temporarily stored outside the firewall of the mail server network. A pool means is provided, and reference means for referring to the electronic data stored by the pool means is provided inside the firewall of the mail server network. Has been established.

Further, according to the present invention, there is provided the electronic data transmitted outside the firewall of the mail server network to the communication means of the client network via the information server. A pool means for temporarily storing the electronic data, and a delivery means for passing the electronic data to be transmitted to the pool means inside the firewall of the mail server network, wherein the information server of the mail server network comprises: The electronic data stored by the means is taken out and returned to the communication means of the client network.

The present invention according to claim 14 is a method for temporarily storing an e-mail transmitted from the client network to the information server of the mail server network outside a firewall of the mail server network. And a step of referring to the stored e-mail from the inside of the firewall of the mail server network. An e-mail transmission / reception program for causing a computer to execute the steps is recorded on a computer-readable recording medium. Have been.

Further, according to the present invention, an electronic mail returned from the mail server network to the client network via the information server is sent from inside the firewall of the mail server network. Delivering to the outside, temporarily storing the delivered e-mail outside the firewall of the mail server network, extracting the stored e-mail and replying to the client network The method is characterized in that an e-mail transmission / reception program for causing the computer to execute the step and the step is recorded on a computer-readable recording medium. BRIEF DESCRIPTION OF THE FIGURES FIG. 1 is a diagram showing an entire configuration of an e-mail system according to a first embodiment of the present invention;

Figure 2 is a diagram showing the configuration within the client network according to Figure 1;

Figure 3 is a diagram showing the configuration within the mail server network according to Figure 1;

4 is a flowchart at the time of sending an e-mail according to the first embodiment of the present invention. FIG. 5 is a flowchart of a login process according to FIG.

Figure 6 is a flowchart of the login process according to Figure 4;

FIG. 7 is a flowchart of the mail sending process according to FIG. 4;

FIG. 8 is a flowchart of the log processing according to FIG. 4;

FIG. 9 is a flowchart at the time of receiving an e-mail according to the first embodiment of the present invention. FIG. 10 is a flowchart in the mail information acquisition processing according to FIG. 9;

FIG. 12 is a flowchart of a mail buffer deletion process according to FIG. 9; FIG. 13 is a diagram showing a configuration in a mail server network according to a second embodiment of the present invention;

FIG. 14 is a flowchart of a communication process performed in the mail server network according to FIG. 13;

FIG. 15 is a flowchart of communication processing performed in the mail server network according to FIG. 13;

FIG. 16 is a flowchart of a communication process performed in the mail server network according to FIG. 13;

FIG. 17 is a diagram showing the overall configuration of a conventional e-mail system. BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings. Figure

1 is a diagram showing the overall configuration of the e-mail system according to the present embodiment, FIG. 2 is a diagram showing the configuration in the client network according to FIG. 1, and FIG. 3 is a diagram showing the configuration in the mail server network according to FIG. It is.

As shown in FIG. 1, a client network 1 provided in an organization such as an in-house LAN is connected to a mail server network 2 via an internet. The client network 1 has a firewall 3 between itself and the outside Internet. The firewall 3 restricts communication of electronic mail protocols (SMTP, POP). In addition, the firewall 3 installed in the client network 1 permits communication of the HTTP protocol.

(Hereinafter, simply referred to as data) can pass through the firewall 3.

The mail server network 2 is provided with an e-mail server 4 (hereinafter, referred to as a mail server) capable of transmitting and receiving e-mail (hereinafter, simply referred to as e-mail) with other networks.

The client network 1 and the mail server network 2 are connected to the Internet by network devices such as a terminal adapter (TA) and a router, respectively.

As shown in FIG. 1, a virtual mail server 5 for sending and receiving mail to and from a mail server 4 in a mail server network 2 is installed in the client network 1 in the present embodiment.

As shown in the figure, the mail server network 2 is a web server 6 as an information server for publishing information on the Internet and capable of transmitting and receiving HTTP protocol data, and the client network 1 Virtual mail server 5 and the mail server 4 of the mail server network 2 A mediation server 7 that mediates the transmission and reception of e-mail between the Web server 6, a control unit 8 that processes and controls data communicated between the web server 6 and the mediation server 7, and an encryption unit 9 that will be described later. A decoding unit 10 is provided.

With the configuration of the virtual mail server 5 and the mediation server 7, etc., e-mail can be easily transmitted using general-purpose e-mail software 11 (hereinafter simply referred to as e-mail software) running on a computer in the client network 1. Can send and receive. The details are described below.

As shown in FIG. 2, the virtual mail server 5 in the client network 1 is realized by a program and a CPU stored in a computer in the client network 1, and includes a virtual outgoing mail server 51 and a virtual incoming mail. The server includes a server 52, a communication unit 53, a request unit 54, a control unit 55, a transmission buffer 56, and a reception buffer 57 as mail holding means.

The virtual transmission mail server 51 functions as a transmission mail server in the client network 1, and the virtual reception mail server 52 functions as a reception mail server in the client network 1. This virtual transmission mail server 51 receives a transmission mail when a mail is transmitted from the mail software 11, similarly to a general transmission mail server (for example, an SMTP server). Here, if it is an outgoing mail server such as a general SMTP server, the outgoing mail is directly delivered to the address specified in the received outgoing mail, but this virtual outgoing mail server 51 transmits this outgoing mail. Transfer to the sending buffer 56 in the same virtual mail server 5. Similarly to a general receiving mail server (for example, a POP server), the virtual receiving mail server 52 responds to a mail receiving request of the mail software 11 and converts the mail stored in the receiving buffer 57 into the mail software. 1 Reply to 1.

The communication unit 53 of the virtual mail server 5 has a basic function as a Web browser, and the Web server 6 of the mail server network 2 and the HTTP It can communicate by protocol. The communication unit 53 includes a transmission unit 53 a that transmits data to the web server 6 of the mail server network 2 and a reception unit 53 b that receives data from the web server 6. The communication unit 53 communicates with the Web server 6 of the mail server network 2 via the transmission unit 53 a and the reception unit 53 b of the communication unit 53. More specifically, the transmission unit 53a of the communication unit 53 transmits various commands and authentication information described later, and the reception unit 53b receives a response to the command.

The communication unit 53 includes an encryption unit 53c for encrypting data to be transmitted and a decryption unit 53d for decrypting the (encrypted) received data. That is, the data transmitted from the communication unit 53 is decrypted by the encryption unit 53 c and transmitted to the Web server 6 of the mail server network 2. Conversely, data returned from the Web server 6 is encrypted as described later, and the data is decrypted by the decryption unit 53d. Accordingly, all communication data flowing on the Internet between the virtual mail server 5 and the Web server 6 of the mail server network 2 is encrypted, and the security for data communication is enhanced.

The control unit 55 of the virtual mail server 5 controls the processing and the data performed in the virtual mail server 5.

The request section 54 of the virtual mail server 5 requests the control section 55 to acquire the mail information or mail stored in the mail server 4 of the mail server network 2.

The sending buffer 56 in the virtual mail server 5 holds and sends mail to be sent to the mail server 4 of the mail server network 2. The receiving buffer 57 serving as mail holding means has a mail server network. The mail received from the mail server 4 of the work 2 is stored. The reception buffer 57 and the transmission buffer 56 are configured by a storage device such as a memory provided in a computer in the client network 1. As shown in Fig. 3, the mail server 4 of the mail server network 2 is composed of a general outgoing mail server 4 1 (for example, an SMTP server) and a receiving mail server 4 2

(For example, a POP server), which sends mail to another network on the Internet or receives mail from a mail server on another network. The receiving mail server 42, which also functions as an authentication server for access from the client network, has a registration table for user authentication.

(Not shown) is provided, and authentication to the receiving mail server 42 is performed by determining whether or not the user is registered in this table.

The mediation server 7 of the mail server network 2 is realized by a program, a CPU, and the like stored in a computer in the mail server network 2, and as shown in FIG. A section 72, a return section 73, an authentication section 74, an identifier assigning section 75, and buffers A to D are provided. It should be noted that a plurality of the mediation servers 7 can be provided in the mail server network 2.

Here, a unique address is assigned to the mediation server 7 of the mail server network 2, and the virtual mail server 5 of the client network 1 accesses the web server 6 by specifying the address and It becomes possible to access the mediation server 7 corresponding to the address. The details will be described later.

The mail sending unit 71 of the mediation server 7 sends the mail received by the Web server 6 to the sending mail server 41 when the mail is sent from the client network 1. When the mail is sent to the reply mail server of mail server 4, the mail is delivered to the specified address.

The mail acquisition unit 72 of the mediation server 7 acquires mail information or mail stored in the reception mail server 42 in response to a request from the request unit 54 of the client network 1. The reply unit 73 of the mediation server 7 returns the mail information or mail acquired by the mail acquisition unit 72 to the virtual server of the client network 1.The authentication unit 74 of the mediation server 7 includes the client network The first communication unit 53 requests the reception mail server 42 of the mail server 4 to perform authentication based on the authentication information transmitted from the transmission unit 53 a of the communication unit 53.

The identifier assigning unit 75 of the mediation server 7 assigns an identifier to the authentication information when the authentication is successful by the authentication unit 74, and returns the identifier to the virtual server of the client network 1. It is. By adding this identifier to the data to be transmitted, the virtual mail server 5 can authenticate the receiving mail server 42 without transmitting the actual authentication information, thereby increasing the safety of data communication. The details will be described later.

The buffers A to D in the mediation server 7 are configured by a storage device such as a memory or a hard disk, and various information is held and stored in the buffers.

Here, the control unit 8 of the mail server network 2 processes and controls the data communicated between the We server 6 and the mediation server 7 as described above. It is realized by a program stored in another computer, for example, a CGI (Common Gateway Interface) program and a CPU.

In addition, the mail server network 2 includes an encryption unit 9 for encrypting the data to be transmitted, and an encryption unit 9 corresponding to the encryption unit 53 c and the decryption unit 53 d of the communication unit 53 of the virtual mail server 5. A decryption unit 10 for decrypting (encrypted) received data is provided. The virtual mail server 5 and the mail server are formed by the encryption unit 9, the decryption unit 10 of the mail server network 2, and the encryption unit 53 c and the decryption unit 53 d of the communication unit 53 of the virtual mail server 5. All communication data on the Internet with the Web server 6 on the network 2 is encrypted. This encryption includes Various encryption technologies such as SSL (Secure Socket Layer) can be used. Next, when sending an e-mail in the e-mail system of the present embodiment, the e-mail is sent from the e-mail software 11 running on the computer in the client network 1 to the e-mail server 4 of the e-mail server network 2 immediately. The operation when transmitting is described. FIG. 4 is a flow chart in the case where mail is transmitted from the mail software 11 to the transmission mail server 41 of the mail server network 2.

First, mail is transmitted from the mail software 11 in the client network 1 to the virtual transmission mail server 51 of the virtual mail server 5 (S 1).

The virtual sending mail server 51 of the virtual mail server 5 detects that the mail has been sent from the mail software 11, and receives the mail (S2). Then, authentication is performed in the virtual transmission mail server 51 (S3). In this authentication, the above mail is a mail transmitted from mail software 11 running on the same computer as the computer on which the virtual mail server 5 is installed (hereinafter referred to as a virtual mail server computer). It is performed by judging whether or not. More specifically, this is performed by confirming whether the IP address of the virtual mail server computer is the same as the IP address of the computer on which the mail software 11 is running. In this way, the security against e-mail transmission is enhanced by allowing transmission only from the same computer as the virtual mail server computer.

If the IP address is not the same here, it means that the mail has been sent from a computer other than the virtual mail server computer, so the virtual outgoing mail server 51 rejects the above authentication and The error information to that effect is sent back to the mail software 11 that sent the mail (S 4), and the processing ends (S 9). On the other hand, if the above IP address is the same, the virtual mail server computer This means that the mail was sent from the same computer as overnight, so the above authentication was successful, and the virtual sending mail server 51 transfers the mail to the sending buffer 56 in the virtual mail server 5 and holds it ( S5).

Thereafter, communication is performed between the virtual mail server 5 of the client network 1 and the mediation server 7 of the mail server network 2, and the following login processing (S6), mail transmission processing (S7), and logout processing are performed. (S8) is performed. As a result, the mail stored in the transmission buffer 56 of the virtual mail server 5 is sent to the mail server 4 of the mail server network 2, and the mail transmission is completed (S9).

The communication between the virtual mail server 5 of the client network 1 and the mediation server 7 of the mail server network 2 is basically performed by the control unit 55, the communication unit 53, and the mail server network of the virtual mail server 5. 2 through the Web server 6 and the control unit 8. This is the same in the mail receiving process described later.

Here, the login process (S6) will be described in more detail. The above-mentioned login processing is for authenticating (login) whether or not the user is a person who is permitted to use the mail server 4 of the mail server network 2. FIG. 5 and FIG. 6 are flowcharts in the login process according to FIG.

First, the control unit 55 of the virtual mail server 5 sends an “HI” command to the control unit 8 of the mail server network 2 to inquire the currently available mediation server 7 in the mail server network 2 (S6-1). ).

Control unit 8 of mail server network 2 When this "HI" command is received, it is determined whether there is a mediation server 7 currently available in mail server network 2 (S6-2) ).

If there is no mediation server 7 currently available, the login process is stopped and the control unit 8 of the mail server network 2 responds to the “HI” command and Error information is returned to the virtual transmission mail server 51 (S6-3). The virtual transmission mail server 51 that has received the error information returns the error information to that effect to the mail software 11 that transmitted the mail (S6-4), and ends the mail transmission processing. (S6-5).

On the other hand, if there is a mediation server 7 currently available in the mail server network 2, the control unit 8 of the mail server network 2 responds to the “HI” command by using the mediation server available in the mail server network 2. The address corresponding to the server 7 is returned to the control unit 55 of the virtual mail server 5 (S6-6). If a plurality of mediation servers 7 are installed in the mail server network 2 and there are a plurality of available mediation servers 7, the most suitable among these mediation servers 7 is to consider access from other users. The mediation server 7 is automatically selected by the control unit 8 of the mail server network 2.

When the control unit 55 of the virtual mail server 5 receives the above address, the control unit 55 of the virtual mail server 5 checks “HELL〇” for confirming whether or not the mediation server 7 corresponding to the above address is operating normally. A command is sent to the control unit 8 of the mail server network 2 (S6-7). Note that this “HELLO” command is sent by specifying the address returned above.

The control unit 8 of the mail super network 2 receiving the "HELL @" command selects the mediation server 7 corresponding to the address, and inquires of the mediation server 7 whether or not it is operating normally. If the mediation server 7 is operating normally, the mediation server 7 responds, and in response to the response from the mediation server 7, the control unit 8 of the mail server network 2 sends “OK” as a response to the “HELLO” command. Reply to 55 (S6-8). Thereafter, the following processing is performed on the mediation server 7 corresponding to this address.

Here, after transmitting the “: HELL〇” command, the control unit 55 of the virtual mail server 5 monitors whether or not the “〇K” is received within a predetermined time (S6-9). If the response of “OK” is not received within a predetermined time, it is determined that the mediation server 7 has not been started (or is abnormal), and the control unit 55 of the virtual mail server 5 transmits the virtual transmission mail. The error information to that effect is returned to the mail software 11 via the server 51 (S6-110), and the processing ends (S6-11-1).

When the control unit 55 of the virtual mail server 5 receives the above response “〇Κ” within a predetermined time, next, it is determined whether or not the user of the mail software 11 is a user registered in the mail server 4. A “LOG IN” command requesting the authentication is sent to the control unit 8 of the mail server network 2 (S6-12). When transmitting this “L〇GIN” command, the user name and password (authentication information) entered by the user in the mail software 11 are transmitted together.

The control unit 8 of the mail server network 2 that has received the “L〇GIN” command instructs the authentication unit 74 of the mediation server 7 to perform authentication. In response, the authentication unit 74 of the mediation server 7 requests the received mail server 42 for authentication based on the transmitted user name and password (S6-13). If the above authentication fails, the control unit 8 of the mail server network 2 returns error information to the virtual transmission mail server 51 as in S6-3 to S6-5 described above, and the process ends. (S6-14 to S6-16).

On the other hand, if the authentication is successful, the authentication unit 74 of the mediation server 7 stores the user name and the password as the above-mentioned authentication information in the buffer A in the mediation server 7 (S6-17). Then, the identifier assigning unit 75 of the mediation server 7 assigns a unique identifier X1 (Connection ID) to the authentication information (S6-18), and the identifier assigning unit 75 mediates the identifier XI. The data is stored in buffer B in server 7 (S6-19). The identifier XI is sent to the control unit 8 of the mail server network 2 by the identifier assigning unit 75, and the control unit 8 sends the identifier X1 as a response to the “LOG IN” command to the control unit of the virtual mail server 5. Reply to 55 (S 6— PT P99 / 06351

20

Upon receiving this identifier XI (S6-21), the control unit 55 of the virtual mail server 5 performs authentication using this identifier X1 in the next mail sending process (S7). In general, when sending an e-mail, it is not necessary to authenticate the user. However, in the present embodiment, even when sending an e-mail as described above, the user must be authenticated to the receiving mail server 42. As a result, the security against mail transmission is improved.

Next, the mail sending process (S7) will be described in more detail. The above-mentioned mail sending process is to send the mail held in the sending buffer 56 in the virtual mail server 5 to the mail server 4 of the mail server network 2 in S5 described above. FIG. 7 is a flowchart of the mail sending process shown in FIG. 4. In the mail sending process, the control unit 55 of the virtual mail server 5 first sends a “SEND” command for sending the mail to be sent to the mail server network 2. (S7-l). When transmitting the "SEND" command, the mail held in the transmission buffer 56 in the virtual mail server 5 and the identifier X1 returned in the login process (S6) are transmitted together. By transmitting the identifier XI, the authentication in the mediation server 7 can be performed without transmitting the user name and the password as the actual identification information, and the security of the transmission and reception of the mail is improved.

That is, the control unit 8 of the mail server network 2 receiving the “SEND” command and the above identifier instructs the authentication unit 74 of the mediation server 7 to perform authentication in the same manner as described above. The authentication unit 74 of the server 7 checks whether the identifier is the same as the identifier (XI) stored in the buffer B in S6-19 of the login process described above (whether the identifier is valid). (S 7-1 2). If the identifier stored in the buffer B and the received identifier are the same, the authentication to the receiving mail server 42 has already been performed in S6-13 of the above login processing. The testimony is guaranteed to be successful. In this way, by reducing the chance that authentication information, such as the actual user name and password, will flow through the Internet, the security of sending and receiving e-mail will be increased.

On the other hand, if the received identifier is not the same as the identifier XI stored in the buffer B, the authentication in S6-13 of the above login process is not guaranteed, and the control unit 8 of the mail server network 2 sends the virtual outgoing mail. The error information is returned to the server 51, and the process ends (S7_3 to S7-5).

When the authentication unit 74 of the mediation server 7 confirms that the identifiers are the same, the control unit 8 of the mail server network 2 stores the received mail in the buffer C of the mediation server 7 (S7 — 6), instruct the mail sending unit 71 of the mediation server 7 to send the mail to the receiving mail server 42. In response, the mail sending section 71 of the mediation server 7 transfers the mail stored in the buffer C to the sending mail server 41 and sends it out (S7-7). When the sending of the mail is completed, the mail stored in the buffer C in the mediation server 7 becomes unnecessary and is deleted (S7-8).

Next, the identifier assigning unit 75 of the mediation server 7 assigns a new identifier X2 instead of the identifier X1 (S7-13), and stores this identifier X2 in the buffer B in the mediation server 7 (S7 _ 14). The identifier X2 is sent to the control unit 8 of the mail server network 2 by the identifier assigning unit 75 of the mediation server 7, and the control unit 8 transmits the identifier X2 to the virtual mail server 5 as a response to the "SEND" command. Is returned to the control unit 55 (S7-15).

Upon receiving this identifier X2 (S7-16), the control unit 55 of the virtual mail server 5 performs authentication using this identifier X2 in the next logout process (S8). In this way, a new identifier is assigned each time, and the identifier is changed during a series of data communication with the communication unit of the client network.Therefore, even if someone acquires the data of the identifier flowing on the Internet, Book using that identifier The possibility of using an e-mail system is reduced, and the security for sending and receiving e-mail is increased.

Next, the logout process (S8) will be described in more detail. The log-out processing is for canceling (log-out) the above-mentioned login state. FIG. 8 is a flowchart in the log processing according to FIG.

In the logout process, first, the control unit 55 of the virtual mail server 5 transmits a “LOGOUT” command for canceling the login state to the control unit 8 of the mail server network 2 (S8-1). When transmitting the “LOG @ UT” command, the identifier X2 returned as a response to the “SEND” command is also transmitted. Then, upon receiving the “L〇GOUT” command, the control unit 8 of the mail server network 2 instructs the authentication unit 74 of the mediation server 7 to perform authentication in the same manner as in the processing of the “SEND” command described above. The authentication unit 74 performs authentication by determining the validity of the identifier X2 (S8-2, S8-3 to S8-5).

If the above identifier is determined to be valid, it becomes unnecessary by logout. Buffer A (in which the user name and password are stored) and Buffer B (in which the identifier is stored) in the mediation server 7 are connected to the mail server network 2 Is deleted by the control unit 8 of the virtual mail server 5 (S8-6), and "OK" indicating that the logout process is completed normally is returned to the control unit 55 of the virtual mail server 5 as a response to the "LOGOUT" command (S8-6). 8—7). Then, upon receiving the above “OK:” (S8-8), the control unit 55 of the virtual mail server 5 completes the mail transmission (S9).

Next, when receiving e-mail in the e-mail system of the present embodiment, the mail stored in the mail server 42 (receiving mail server) of the mail server network 2 is immediately sent to the mail software 11 of the client network 1. The operation when receiving is described. Fig. 9 shows the flow for receiving mail from mail server 42 of mail server network 2 to mail software 11 It is a chart.

First, the mail software 11 in the client network 1 requests the virtual mail server 52 of the virtual mail server 5 to receive mail (S11). In response to the request from the mail software 11, the virtual mail server 52 of the virtual mail server 5 performs authentication in the virtual mail server 52 (S12). This authentication is performed by determining whether or not the request is a request from a user registered in a registration table (not shown) prepared in advance in the virtual mail server 5. If the request is not a request from a user registered in this registration table, the virtual receiving mail server 52 rejects the above authentication and sends error information to that effect to the mail software 11 requesting the mail reception. Reply and end the process (S13). On the other hand, if the request is from a user registered in the registration table, the request unit 54 of the virtual mail server 5 sends a request to the control unit 55 of the virtual mail server 5 to the mail server network 2. Instructs to request e-mail stored in mail server 4. In response, the control unit 55 of the virtual mail server 5 first performs a login process (S14). In this login processing (S14), the same processing as in the above-described mail transmission is performed, and the identifier XI is returned to the control unit 55 of the virtual mail server 5 as a response to the "LOGIN" command. The details are omitted.

In the case of the above-described mail transmission log-in processing, the processing was performed mainly on the virtual transmission mail server 51, but in the case of mail reception log-in processing, the processing was performed mainly on the virtual reception mail server 52. Processing is performed. This applies not only to the login processing but also to the processing described below.

When the login process (S14) ends, the mail information acquisition process is performed. This mail information acquisition processing is for acquiring information on mail stored in the mail server 4 of the mail server network 2 (hereinafter referred to as mail information). FIG. 10 is a flowchart of the mail information acquisition process according to FIG. T

twenty four

It is.

In the mail information acquisition process, first, the control unit 55 of the virtual mail server 5 executes a “LIST” command for acquiring mail information of the mail currently stored in the receiving mail server 42 of the mail server network 2. Is transmitted to the control unit 8 of the mail server network 2 (S15-1). When transmitting this "LIST" command, the mail information of the mail currently stored in the reception buffer 57 in the virtual mail server 5 and the identifier XI returned in the login process (S14) are transmitted together. Then, similarly to the above, the control unit 8 of the mail server network 2 that has received the “LI ST” command instructs the authentication unit 74 of the intermediary server 7 to perform authentication, and the authentication unit 74 sets the identifier X Authentication is performed by judging the validity of 1 (S15-2, S15-3 to S15-5).

When it is determined that the identifier is valid, the mail acquisition unit 72 of the mediation server 7 acquires the mail information of the mail stored in the reception mail server 42 (S15-6). Then, the obtained information is compared with the mail information transmitted together with the above “LIST” command, and the mail that has not yet been obtained on the virtual mail server 5 side (the reception buffer 57 of the virtual mail server 5) (hereinafter referred to as “mail”). , New mail) (S15-7).

If there is a new mail, the mail acquisition unit 72 of the mediation server 7 acquires the new mail from the receiving mail server 42 (S15-8), and stores the new mail in a buffer in the mediation server 7. Save to D (mail buffer) (S15-9). If there is no new mail, these processes (S15-8, S15-9) are not performed and the next process is performed. When new mail is acquired from the receiving mail server 42, the mail is sent to the receiving mail server 42 based on the user name and the password stored in the buffer A in the mediation server 7 in the login process (S14). Authentication is performed.

Following the above processing, the identifier assigning unit 75 of the mediation server 7 A new identifier X2 instead of the identifier XI transmitted with the command is given (S15-10), and the new identifier X2 is stored in the buffer B in the mediation server 7 (S15-5-11). Then, the identifier X 2 is sent to the control unit 8 of the mail server network 2 by the identifier assigning unit 75, and the mail information obtained by the mail obtaining unit 72 is sent to the control unit 8 of the mail server network 2 by the reply unit 73. Can be The control unit 8 returns the identifier X2 and the mail information to the control unit 55 of the virtual mail server 5 as a response to the "LIST" command (S15-12).

The control unit 55 of the virtual mail server 5 having received these information (S15-13) compares the returned mail information with the mail information stored in the reception buffer 57 in the virtual mail server 5, and It is determined whether there is any new mail (S16). If it is determined that there is no new mail, logout processing is performed without performing the following processing (S17), and the request unit 54 of the virtual mail server 5 is transmitted via the virtual reception mail server 52 of the virtual mail server 5. Then, information indicating that there is no new mail is returned to the mail software 11 (S18), and the processing for the mail reception request is completed (S26).

On the other hand, if it is determined that there is new mail, the control unit 55 of the virtual mail server 5 stores the returned mail information in the reception buffer 57 in the virtual mail server 5 (S19), and the following will be described. A mail acquisition process is performed (S20).

The mail acquisition processing (S20) is for acquiring mail from the buffer D in the mediation server 7 of the mail server network 2. FIG. 11 is a flowchart of the mail acquisition process according to FIG.

In the mail acquisition process, first, a “READ” command for acquiring mail is sent to the control unit 8 of the mail server network 2 (S20-1). When transmitting the "READ" command, the mail number of the mail to be obtained and the identifier X2 returned in the mail information obtaining process (S15) are transmitted together. And, as above, "READ" The control unit 8 of the mail server network 2 that has received the command instructs the authentication unit 74 of the mediation server 7 to perform authentication, and the authentication unit 74 performs authentication by determining the validity of the identifier X2 ( S20-2, S20_3 to S20-5).

If it is determined that the identifier is valid, the mail acquisition unit 72 of the mediation server 7 acquires the mail corresponding to the mail number transmitted with the “READ” command from the buffer D in the mediation server 7 (S 20 — 6). Then, the identifier assigning unit 75 of the mediation server 7 assigns a new identifier X3 instead of the identifier X2 transmitted with the "READ" command (S20-7), and stores this in the buffer B.

(S20-8). The identifier X 3 is sent to the control unit 8 of the mail server network 2 by the identifier assigning unit 75, and the mail acquired by the mail acquiring unit 72 is sent to the mail server network by the reply unit 73 of the mediation server 7. It is sent to the control unit 8 of 2. The control unit 8 returns the identifier X3 and the mail to the control unit 55 of the virtual mail server 5 as a response to the “READ” command (S20-9).

Upon receiving the above information (S20-10), the control unit 55 of the virtual mail server 5 stores the returned mail in the reception buffer 57 in the virtual mail server 5 (S21).

Next, a mail buffer deletion process (S23) is performed. This mail buffer deletion processing (S23) deletes the mail stored in the buffer D (mail buffer) in the mediation server 7 of the mail server network 2 described above. FIG. 12 is a flowchart of the mail buffer deletion process according to FIG. This mail buffer deletion process is a process that can be arbitrarily specified by the user. Whether the user has specified to perform the mail buffer deletion process before performing the mail buffer deletion process (S23) Is determined by the control unit 55 of the virtual mail server 5 (S22). Specify to delete mail buffer If not, a logout process (S24) and a process of returning a mail to the mail software 11 (S25) described below are performed without performing the mail buffer deletion process.

In the mail buffer deletion process, first, the control unit 55 of the virtual mail server 5 sends a “DEL” command for deleting the mail buffer D to the control unit 8 of the mail server network 2 (S23_l). When transmitting this “DEL” command, the mail number of the mail to be deleted and the identifier X3 returned in the mail acquisition processing (S20) are transmitted together. Then, similarly to the above, the control unit 8 of the mail server network 2 that has received the “DEL” command instructs the authentication unit 74 of the mediation server 7 to perform authentication, and the authentication unit 74 checks the validity of the identifier X2. Authenticate by judgment (S23_2, S23-3-S

If the above identifier is determined to be valid, the control unit 8 of the mail server network 2 searches the mail buffer D in the mediation server 7 for a mail corresponding to the mail number transmitted together with the “DEL” command, The mail is deleted (S23-6). Then, the identifier assigning unit 75 of the mediation server 7 assigns a new identifier X4 instead of the identifier X3 transmitted with the "DEL" command (S23-7), and stores this in the buffer B (S23-7). 23-8). Subsequently, the identifier assigning unit 75 sends the identifier X4 to the control unit 8 of the mail server network 2, and the control unit 8 sends the identifier X4 to the control unit 55 of the virtual mail server 5 as a response to the "DEL" command. Reply (S23-9).

Upon receiving the above information (S23-10), the control unit 55 of the virtual mail server 5 performs a logout process (S24). The logout process is the same as the above-described case of the mail transmission, and thus the description is omitted.

After the logout process, the control unit 55 of the virtual mail server 5 sends the new mail stored in the reception buffer 57 of the virtual mail server 5 to the mail software 1 1 The virtual mail server 52 instructs the virtual mail server 52 of the virtual mail server 5 to send the new mail to the mail software 11 (S25).

Thus, the processing for the mail reception request from the mail software 11 is completed (S26).

Here, the request unit 54 of the virtual mail server 5 requests the control unit 55 of the virtual mail server 5 to request e-mail stored in the mail server 4 of the mail server network 2 at predetermined time intervals. You can also instruct. In this case, the processing from S12 to S24 described above is performed, and the new mail is automatically accumulated in the reception buffer 57 in the virtual mail server 5.

Here, in the mail server network 2 in the present embodiment, the firewall 3 as installed in the client network 1 is not installed. If a firewall that restricts the protocol used for sending and receiving mail is also installed in the mail server network 2, the Web server 6, control unit 8, and encryption unit of the mail server network 2 are used. 9. The decryption unit 10 is installed outside the firewall, and a reference unit (not shown) capable of referring to electronic data in the control unit 8 (or the Web server 6) is provided to the mediation server 7 This will allow e-mail transmission and reception. In this case, the reference unit of the mediation server 7 can communicate with the control unit 8 using a protocol (for example, HTTP protocol) that can pass through the firewall, and the control unit 8 can hold an instruction to the mediation server 7 And

The reference unit of the mediation server 7 refers to the instruction stored in the control unit 8 by the HTTP protocol at predetermined time intervals. (This is possible because the HTTP protocol can pass through the firewall of the mail server network.) Is). When the instruction is stored in the control unit 8, the reference unit of the mediation server 7 acquires the instruction and gives an appropriate instruction to each unit in the mediation server 7. The instruction is stored in the control unit 8. If not, do nothing. As a result, even when the above-described firewall is installed in the mail server network, it is possible to send out the mail transmitted from the client network to the mail server 4 and the like.

Hereinafter, the details will be described in detail as a second embodiment of the present invention. Note that portions that are not particularly described are the same as those in the above-described first embodiment.

Here, even when a firewall is installed in the mail server network 2, a Web server 6, a control unit 8, an encryption unit 9, and a decryption unit 10 are provided in the firewall, If communication is performed with the client network 1 using a protocol (for example, HTTP protocol) that can pass through the firewall, it is possible to send and receive e-mails with the same configuration as described above. However, it is considered that communication between the Web server 6 and the client network 1 is often performed using a port different from a normal port (for example, port number 80). Therefore, it is necessary to make the new port accessible to the external network (Internet). Making the new port accessible to the external network in this manner may cause the security of the mail server network 2 to be reduced.

Therefore, in the second embodiment of the present invention, as described above, a Web server or the like is installed outside the firewall, and electronic data in the control unit (or Web server) can be referred to. By providing the reference unit in the above-mentioned mediation server, it is possible to send and receive e-mails without having to make a new port accessible to an external network.

FIG. 13 is a diagram showing a configuration in the mail server network according to the present embodiment.

As shown in the figure, the mail server network 2 of this embodiment has a mail server. —Firewall 12 is installed, including bar 4. It is assumed that the firewall 12 permits HTTP protocol communication, similarly to the firewall 3 installed in the client network 1.

The mediation server 7 described in the first embodiment is provided inside the firewall 12. The mediation server 7 has a pool in addition to the configuration described in the first embodiment. A control unit 76 is provided. Further, a Web server (Web server A13) as an information server, an encryption unit 9, and a decryption unit 10 are provided outside the above-mentioned firewall 12 and furthermore, a firewall 12 is provided. Externally, control unit A14, pool 15, Web server B 16, and control unit B

17 are provided.

In the first embodiment, the communication between the virtual mail server 5 of the client network 1 and the mediation server 7 of the mail server network 2 is performed via the web server (6 in FIGS. 1 and 3). In this embodiment, the web server A 13 as an information server, the control unit A 14, the pool 15, the control unit B 17, the web server B 16, and the pool control unit of the mediation server 7 This will be done via 76. The details will be described later.

The pool 15 stores electronic data communicated between the virtual mail server 5 of the client network 1 and the mediation server 7 of the mail server network 2, and is stored in a computer in the mail server network 2. It is composed of a storage device such as a provided memory. The control unit A 14 and the control unit B 17 store the electronic data in the pool 15 or acquire the electronic data stored in the pool 15, and are stored in the mail server network 2. Combination

—It is realized by programs stored in the evening, such as the CGI (Common Gateway Interface) program and CPU. The electronic data communicated between the virtual mail server 5 of the client network 1 and the mediation server 7 of the mail server network 2 by the control unit A 14, the pool 15, and the control unit B 17. Pool means for temporarily storing evenings is realized.

Here, the pool control unit 76 of the mediation server 7 includes a reference unit that refers to the electronic data stored in the pool 15 and a control unit that uses the electronic data stored in the pool 15 as a pool unit. It functions as a delivery means to hand over to B17. The pool control unit 76 has a basic function as a Web browser, and can communicate with the Web server B 16 of the mail server network 2 using the HTTP protocol. Also, the pool control unit 76 performs processing performed by the control unit 8 in the first embodiment on the mediation server 7, for example, an instruction to send an e-mail to the e-mail transmission unit 71, an instruction to perform an authentication to the authentication unit 74, and the like. It also does.

Next, a communication operation between the client network 1 and the mail server network 2 in the present embodiment will be described. The processing performed in the client network 1 and the processing performed in the mediation server 7 in the mail server network 2 are the same as those in the first embodiment described above, and a description thereof will be omitted. Overnight) will be described.

First, commands for performing various processes (such as “HI”, “SEND”, and “LIST” commands in login processing, mail sending processing, mail acquisition processing, and logout processing) are virtual mails in the client network 1. The operation when the message is transmitted from the server 5 will be described.

The above command is sent from the virtual mail server 5 on the client network 1 to the web server A 13 on the mailer network 2, and the web server A 13 receives this command (S31 in Fig. 14). . As described above, this command is encrypted by the encryption unit 53 c of the communication unit 53 of the client network 1, and is thus decrypted by the decryption unit 10 of the mail server network 2. (S32).

The decrypted command is temporarily stored in the pool 15 by the control unit A14 (functioning as a pool means) (S33). W

32

On the other hand, the pool control unit 76 of the mediation server 7 starts the following reference processing (FIG. 15) at predetermined intervals, for example, every 5 seconds or 10 seconds, and a command is transmitted from the client network 1. I always check to see if I have

First, the pool control unit 76 having a browser function accesses the web server B 16 using a protocol (the HTTP protocol in the present embodiment) that can pass through the firewall 12 (S41). The web server B 16 accessed by the pool control unit 76 activates the CGI functioning as the control unit B 17, and determines whether or not commands are stored in the pool 15 by the control unit B 17. Is confirmed (S42). If the electronic data is not stored in the pool 15, the reference processing ends here (S 43). When a command is stored in the pool 15, the command is acquired by the control unit B 17 (S 44), and the command is transferred to the pool control unit 76 via the web server B 16. (S45). Then, the pool control unit 76 that has received the command performs a process according to each command (S46), and the reference process ends.

In this way, the pool control unit 76 receiving the above command performs a process according to each command, and a response (the above-described error information, an identifier, etc.) of the mediation server 7 to the command is a delivery process (see FIG. 16) By the processing of the control unit A14, a reply is sent to the virtual mail server 5 of the client network 1.

First, when it becomes necessary for the mediation server 7 to return a response to the virtual mail server 5 of the client network 1, the pool control unit 76 having a browser function accesses the web server B 16 and A response of 7 is sent to the web server B 16 (S51). This is performed by adding (the information of) the response of the mediation server as a parameter when accessing the web server B16.

The web server B 16 receiving the response from the mediation server 7 activates the CGI functioning as the control unit B 17. Then, this control unit B 17 (functions as pool means) As a result, the response of the mediation server 7 is accumulated in the pool 15 (S52), and the bow I passing process ends.

By the way, the control unit A 14 that has accumulated the above-described command in the pool 15 monitors the state of the pool 15 and waits until the response of the mediation server 7 is accumulated in the pool 15 (S34 in Figure 14). Then, when the response of the mediation server 7 is accumulated in the pool 15 by the delivery process, the control unit A 14 acquires the response of the mediation server 7 from the pool 15 (S35), and After the response is encrypted by the encryption unit 9 (S36), it is returned to the virtual mail server 5 of the client network 1 via the Web server A13 (S37).

Thus, the command transmitted from the virtual mail server 5 of the client network 1 is transmitted to the relay server 7 of the mail server network 2, and the response of the relay server 7 to this command is transmitted to the virtual mail server 5 of the client network 1. Will be replied to. Therefore, even when the firewall 12 is installed in the mail server network 2, it is possible to transmit and receive electronic data without making the new port accessible to the external network. .

In the above description, the case where a command is transmitted from the virtual mail server 5 of the client network 1 and the response of the mediation server 7 is returned in response to the command is described. However, the present invention is not limited to this. Information, identifiers, etc.) can be communicated between the virtual mail server 5 in the client network 1 and the mediation server 7 in the mail server network 2. In addition, the encryption unit 9 and the decryption unit 10 of the mail server network 2 need only be located anywhere from the web server A 13 to the pool control unit 76 of the mediation server 7. It can be installed in other places.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and may be implemented in various forms within the scope of the technical idea. These different modes will be described below.

In the present embodiment, the SMTP protocol and the POP protocol are listed as the protocols restricted by the firewall 3 of the client network 1. However, the present invention is not limited to these, and any protocol relating to the transmission and reception of e-mail can be used. There may be.

On the other hand, the HTTP protocol has been described as a protocol that passes through the firewall 3 of the client network 1, but the present invention is not limited to this, and any protocol may be used. In this case, the information server of the mail server network 2 needs to be able to communicate with the protocol.

Further, in the present embodiment, the transmission and reception of the e-mail via the Internet is performed. However, the present invention is not limited to this, and the transmission and reception may be performed via any network.

In the present embodiment, commands are used for sending and receiving e-mails. However, it is not always necessary to use these commands, and when using them, any command may be used in any combination.

In the present embodiment, the mail stored in the receiving mail server 4 2 of the mail server network 2 is temporarily stored in the buffer D in the mediation server 7. However, this is not necessary. At the time of reception, the e-mail may be obtained directly from the receiving mail server 42 of the mail server network 2.

It is needless to say that the authentication using the identifier can be used not only for the transmission and reception of the electronic mail described above but also for the transmission and reception of all kinds of electronic data. For example, the present invention can be applied to transmission and reception of electronic data using various protocols such as FTP and TELNET.

The computer in the client network 1 described above may be any type of computer, for example, a portable computer terminal (network). A mobile phone or the like that can be connected to the network may be used.

As described above, the virtual mail server 5 of the client network 1 is realized by a program and a CPU stored in a computer in the client network 1, but this is not limited to a specific OS. It can be realized in any kind of OS. The same applies to the mediation server 7 of the mail server network 2.

It is also possible to record a program for realizing the electronic mail system according to the present invention on a recording medium readable by a computer. In this case, as the recording medium, any type of recording medium that can read data by computer, such as a floppy disk, a CD-R〇M, a hard disk, and a DVD, can be used.

As described above, the present invention provides an e-mail system for transmitting and receiving e-mail between a client network in which a fire wall is installed and a mail server network including an information server and a mail server. The client network includes a communication means capable of transmitting electronic data that can pass through a firewall, a virtual transmission mail server that receives e-mail from within the client network and transmits the e-mail to the information server via the communication means. The mail server network is provided with mail sending means for sending the sent e-mail to the mail server, or the client network requests the e-mail stored in the mail server. Mail server net with request means The work includes: mail acquisition means for acquiring the electronic mail stored in the mail server; and reply means for returning the acquired electronic mail to the client network in response to the request by the request means. A mail holding means for holding the returned e-mail, and a virtual reception mail server for returning the held e-mail in response to an e-mail reception request. On the client network Even when a firewall is installed, it is possible to send and receive e-mails using general-purpose e-mail software, which has the effect of making sending and receiving e-mails extremely easy.

Also, it is possible to send and receive e-mail using general-purpose e-mail software, and there is no need to communicate with the information server on the mail server network to update the screen of the Web browser. The effect is that the processing can be completed in a short time from the operation of.

The mail server network also has encryption means for encrypting data to be transmitted to the communication means of the client network, and the mail server network has decryption means for decrypting data encrypted by the encryption means of the communication means of the client network. Alternatively, an encryption means for encrypting the data returned by the reply means to the mail server network is provided, and the data encrypted by the encryption means of the mail server network is transmitted to the communication means of the client network. Since it is provided with a decryption means for decrypting, the communication data between the client network and the mail server network is encrypted, and the encrypted communication data is stored on the Internet. It will increase the security of sending and receiving e-mail. This has the effect.

Furthermore, since the request means of the client network requests e-mail at predetermined time intervals, the latest e-mail is stored in the reception buffer in the virtual mail server even if the user does not request e-mail by himself. This has the effect that the user can always obtain the latest e-mail using general-purpose e-mail software.

The communication means of the client network can transmit authentication information to the receiving mail server of the mail server of the mail server network, and authenticate the mail server network to the receiving mail server of the mail server based on the authentication information. E-mail Not only at the time of receiving an e-mail but also at the time of sending an e-mail, since the authentication is performed to the receiving mail server of the mail server network, there is an effect that the security of the e-mail transmission is enhanced.

Further, in an electronic data transmission / reception system for transmitting / receiving electronic data between a client network and a server network having an authentication server for performing predetermined authentication, the client network includes authentication information for the authentication server of the server network. Communication means capable of communicating with the server network. The server network includes an authentication means for requesting authentication to the authentication server based on the transmitted authentication information, and the authentication succeeding. And an identifier assigning means for assigning an identifier to the authentication information when the authentication information has been transmitted, and transmitting the identifier to communication means of the client network. The communication means adds the assigned identifier to the electronic data. One night, the authentication means determines that the identifier added to the electronic data is valid. Since the above authentication is performed by judging whether or not the authentication data is used, authentication can be performed using the identifier, and the chance of actual authentication information flowing on the Internet is reduced. Is increased.

Further, since the identifier assigning means changes the identifier assigned during a series of data communication between the communication means of the client network and the information server, the authentication is not always performed using the same identifier. However, since authentication is performed using different identifiers, even if somebody obtains the data of the identifier flowing on the Internet, it is unlikely that the e-mail system can be used by using the identifier. This has the effect of further enhancing the security of sending and receiving electronic data.

Further, when a firewall including a mail server is installed in the mail server network, and the information server is installed outside the firewall, the electronic data is temporarily stored outside the firewall. Pool hand A step is provided, and reference means for referring to the electronic data accumulated by the pool means is provided inside the firewall. Alternatively, the electronic data transmitted to the inside of the firewall is transmitted to the pool. The information server provided the delivery means for passing the information, and the information server took out the electronic data accumulated by the pool means and returned it to the communication means of the client network.Therefore, a firewall was installed in the mail server network. In this case, e-mail can be sent and received between the client network and the mail server network without making the new port accessible to the external network. This has the effect that the security of the mail server network can be prevented from lowering.

Claims

The scope of the claims

1. A mail network comprising a client network provided with a firewall, an information server capable of transmitting and receiving electronic data that can pass through the firewall of the client network, and a mail server capable of transmitting and receiving electronic mail. An e-mail system that sends and receives e-mail to and from a single network,

The client network includes:

Communication means for communicating electronic data that can pass through the firewall with an information server of the mail server network;

A virtual transmission mail server that receives the e-mail and transmits the e-mail to an information server of the mail server network via the communication means when an e-mail is transmitted from within the client network; Equipped with

In the mail server network,

An electronic mail system comprising: a mail sending unit that sends an electronic mail sent to the information server to the mail server.

2. The communication means of the client network includes an encryption means for encrypting electronic data to be transmitted,

2. The electronic mail system according to claim 1, wherein the mail server network includes a decryption unit that decrypts the electronic data encrypted by the encryption unit of the communication unit of the client network.

3. The client network communication means is capable of transmitting authentication information for a receiving mail server in a mail server of the mail server network, and is transmitted to the mail server network by the client network communication means. Mail server based on the authentication information 3. The e-mail system according to claim 1, further comprising an authentication unit for requesting the server to perform authentication.

4. A mail network comprising a client network provided with a firewall, an information server capable of transmitting and receiving electronic data that can pass through the firewall of the client network, and a mail server capable of transmitting and receiving electronic mail. Email system for sending and receiving emails to and from

In the client network,

Communication means capable of communicating electronic data that can pass through the firewall with an information server of the mail server network;

Requesting means for requesting the electronic mail stored in the mail server of the mail server network,

In the mail server network,

A mail acquisition unit for acquiring the electronic mail stored in the mail server; and, in response to a request by the request unit of the client network, the electronic mail acquired by the mail acquisition unit via the information server to the client network. And reply means for replying to the communication means.

Mail holding means for holding an e-mail returned to the communication means by a reply means of the mail server network;

An e-mail system, comprising: a virtual reception mail server that returns an e-mail held by the e-mail holding means when an e-mail reception request is received from within the client network.

5. The mail server network includes an encryption unit for encrypting the electronic data returned by the return unit,

The communication means of the client network includes the mail server network 5. The e-mail system according to claim 4, further comprising a decryption means for decrypting the electronic data encrypted by the encryption means of the network.

6. The e-mail system according to claim 4, wherein the request means of the client network requests the e-mail at a predetermined time interval.

7. An electronic data transmission / reception system for transmitting / receiving electronic data between a client network and a server network including an authentication server for performing predetermined authentication for an access from the client network,

In the client network,

Communication means capable of communicating authentication information for the authentication server of the server network with the server network;

In the server network,

Authentication means for requesting authentication to the authentication server based on authentication information transmitted by communication means of the client network;

An identifier assigning unit that assigns an identifier to the authentication information when the authentication by the authentication unit is successful, and transmits the identifier to the communication unit of the client network.

The communication means of the client network adds an identifier given by the identifier assigning means of the server network and sends an electronic message, and the authentication means of the server network adds the identifier to the electronic data. An electronic data transmission / reception system, wherein the authentication is performed by determining whether or not the identifier is valid.

8. The electronic data according to claim 7, wherein the server network identifier assigning means changes the assigned identifier during a series of data communications with the client network communication means. Transmission / reception system.

9. A client network with a firewall installed and an email Recording a program for transmitting / receiving an e-mail to / from a mail server network including a mail server capable of transmitting / receiving a mail and an information server capable of transmitting / receiving electronic data capable of passing through a firewall of the client network. A medium,

Receiving e-mail in the client network when e-mail is sent from within the client network;

Transmitting the received e-mail to an information server of the mail server network as an e-mail that can pass through the firewall;

Sending an e-mail sent to the information server of the mail server network to a mail server of the mail server network; and a computer-readable recording medium recording an e-mail transmission / reception program for executing the program on a computer .

10. A mail server comprising a client network provided with a firewall, a mail server capable of transmitting and receiving electronic mail, and an information server capable of transmitting and receiving electronic data capable of passing through the firewall of the client network. A recording medium for recording a program for sending and receiving e-mail to and from a network,

Obtaining e-mail stored in a mail server of the mail server network in the mail server network;

Returning the obtained e-mail to the client network via the information server;

Holding the e-mail returned from the mail server network in a client network;

Returning an e-mail held when the e-mail is received from within the client network; and Computer-readable recording medium recording an e-mail transmission / reception program to be transmitted

11. A recording medium recording a program for transmitting and receiving electronic data between a client network and a server network including an authentication server for performing predetermined authentication for access from the client network. Transmitting authentication information from the client network to an authentication server of the server network;

Requesting authentication from an authentication server of the server network based on the transmitted authentication information;

Assigning an identifier to the authentication information when the authentication to the authentication server is successful;

Transmitting the identifier to the client network; transmitting the electronic data with the identifier added from the client network;

Performing the authentication by determining whether the identifier added to the electronic data in the server network is valid, and reading the electronic data transmission and reception program that causes the computer to execute the authentication. Possible recording medium.

1 2. When a firewall including the mail server is installed in the mail server network, and the information server is provided outside the firewall,

Outside the firewall of the mail server network, there is provided pool means for temporarily storing electronic data transmitted to the information server via the communication means of the client network,

Reference means for referring to the electronic data stored by the pool means is provided inside the firewall of the mail server network. The e-mail system according to claims 1 to 6.

1 3. When a firewall that includes the mail server is installed in the mail server network and the information server is provided outside the firewall,

Pool means for temporarily storing electronic data to be transmitted to the communication means of the client network via the information server is provided outside the firewall of the mail server network; Inside, a delivery means for passing the electronic data to be transmitted to the pool means is provided,

7. The e-mail system according to claim 1, wherein the information server of the mail server network takes out the electronic data stored by the pool unit and returns the electronic data to the communication unit of the client network.

1 4. When a firewall that includes the mail server is installed in the mail server network and the information server is provided outside the firewall,

Temporarily storing an e-mail transmitted from the client network to the information server of the mail server network outside a firewall of the mail server network;

10. The computer-readable recording medium according to claim 9, wherein an electronic mail transmission / reception program for causing a computer to execute the step of referring to the stored electronic mail from inside a firewall of the mail server network is recorded.

15. When a firewall that includes the mail server is installed in the mail server network, and the information server is provided outside the firewall,

The client network from the mail server network via the information server Passing an e-mail returned to the network from inside the firewall of the mail server network to outside;

Temporarily storing the passed e-mail outside a firewall of the mail server network;

10. The computer-readable recording medium according to claim 10, wherein an electronic mail transmission / reception program for causing a computer to execute the step of taking out the stored electronic mail and returning it to the client network is recorded.