JPH05207029A - Electronic mail system - Google Patents

Abstract

PURPOSE:To lighten the burden of a transmitting person in the case that an electronic mail is sent to the user of the network of a different protocol, and simultaneously, to reduce communication time to the irreducible minimum. CONSTITUTION:User information for which protocol conversion is not necessitated is registered to directory servers 13, 16 connected to a network as a real entry, and simultaneously, the user information for which the protocol conversion is necessitated is registered to a virtual entry as the address of a mail gateway 17 capable of executing the protocol conversion to a corresponding protocol system, and when the user information of a receiving person to whom an inquiry request arises from a mail server 12, 15 exists in the virtual entry, the mail server is informed of the address of the mail gateway. Besides, it is retrieved whether the mail address of the transmitting person of the electronic mail exists in a storage means, and only when the mail address of the transmitting person of the electronic mail is registered as the mail address of a transmission permitted person, the electronic mail is transferred.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic mail system for exchanging electronic mail between network systems having different protocol systems.

[0002]

2. Description of the Related Art In recent years, with the widespread use of various network systems and interfaces, there are increasing opportunities to send and receive electronic mail between users of network systems having different protocols. In traditional email systems,
Networks with different protocols are connected by a mail gateway, and the protocols are converted by this mail gateway to exchange e-mail with each other.

When the mail server having the recipient's mailbox is on the network of the same protocol, the electronic mail sent from the sender is temporarily stored in a nearby mail server, and from here, the recipient's mailbox is held. It is transferred to the mail server. On the other hand, if the mail server with the recipient's mailbox is on a network with a different protocol, the sender specified an email gateway that can interpret the recipient's address described in the email and sent the email. .. The mail gateway performs protocol conversion of electronic mail, inquires the address of the transfer destination mail server to the directory server of the other party system, refers to the address returned from the directory server, and sends the electronic mail to the mail server of the other party system. Forwarding mail.

[0004]

In the conventional electronic mail system, when the mail server having the mailbox of the recipient is on the network having a different protocol, the sender can set the address of the mail gateway which can interpret the address of the recipient. It needs to be recorded or recognized. And if your mail gateway is in a remote location,
There was a problem that it took time to communicate with the mail gateway.

In addition, since the conventional electronic mail system does not have a security mechanism for checking the sender of electronic mail at the gateway, an unspecified number of users can access network systems of different protocols through the mail gateway. I was able to send emails to users freely. For this reason,
There is a problem that the system administrator of the network cannot grasp the user who uses the gateway. In addition, the use of e-mail by unspecified number of users,
The rules and restrictions on network operation may not be observed, which may hinder the operation of the system.

The present invention has been made in order to solve the above-mentioned problems of the prior art, reduces the burden on the sender when sending electronic mail to users of network systems having different protocols, and minimizes communication time. The purpose is to provide an electronic mail system which can be limited.

Further, by registering users who can use e-mail at the gateway, e-mail that restricts the use of e-mail by an unspecified number of users, grasps the users, and can operate the system efficiently. The purpose is to provide a system.

[0008]

In order to solve the above problems, in the electronic mail system according to the first invention, user information that does not require protocol conversion is registered as a real entry in a directory server connected on the network. At the same time, the user information that requires protocol conversion is stored as a virtual entry as mail gateway information that can access the actual information (user information) held by the directory server connected to the network of the corresponding protocol system. ..

Further, in the electronic mail system according to the second aspect of the present invention, there are provided storage means for registering a mail address of a specific user who is permitted to send, and searching means for searching the mail address registered in the storage means. When performing the protocol conversion of an electronic mail using a different communication protocol, the searching means searches whether the mail address of the electronic mail sender exists in the storage means. Then, it is determined whether or not the e-mail sender's e-mail address is registered as the sender's e-mail address in the storage means, and the e-mail is transferred only if it is registered.

[0010]

In the electronic mail system according to the first aspect of the present invention, the electronic mail transmitted from the user is temporarily stored in the nearby mail server. The mail server queries the directory server for the address of the mail server that has the recipient's mailbox. The directory server determines whether the user information of the recipient exists in the real entry or the virtual entry, and when it exists in the real entry, notifies the address of the mail server holding the recipient's mailbox. When the user information exists in the virtual entry, the address of the mail gateway that can access the user information held by the directory server connected to the network of the protocol system indicated by the virtual entry is notified. The mail server refers to the address returned from the directory server and forwards the e-mail to the corresponding mail gateway. In the mail gateway, after protocol conversion of e-mail,
The directory server belonging to the converted protocol system is inquired about the address of the transfer destination mail server having the mailbox of the recipient, and the address returned from the directory server is referred to and transferred to the corresponding mail server. In this way, by holding the address of the mail gateway that can interpret the address of the recipient in the directory server as the user information that requires protocol conversion, the mail server is based on the address of the mail gateway returned from the directory server. Emails will be automatically forwarded from to the appropriate mail gateway.

In the electronic mail system according to the second aspect of the present invention, when the electronic mail from the user is received by the mail gateway, whether or not the mail address of the sender described in the electronic mail exists in the storage means. Is retrieved by the retrieval means. Then, it is determined whether or not the sender's email address is registered as the previously-registered sender's email address. If the sender's email address is registered as the sender's email address, the protocol of the email is converted and transferred to the recipient. If it is not registered, it sends an error message back to the sender. As a result, only the email of the user who is permitted to send is protocol-converted and forwarded to the recipient.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the electronic mail system according to the first and second inventions will be described below with reference to the accompanying drawings.

FIG. 1 is a block diagram showing a schematic configuration of an electronic mail system according to the first invention. In the figure,
11 is a workstation having a TCP / IP protocol,
12 is a mail server having TCP / IP protocol, 13 is
Directory server with TCP / IP protocol, 14
A workstation having XNS (Xerox Network System) protocol, 15 is a mail server having XNS protocol, 16 is a directory server having XNS protocol, 17 is a mail gateway having TCP / IP protocol and XNS protocol, and these devices are They are interconnected by an integrated network 18.

The workstations 11 and 14 function as terminal devices when users exchange e-mail, and can access a mail server or a directory server via the integrated network 18.

The mail servers 12 and 15 can access the directory server and other mail servers, and accept and deliver the electronic mail transmitted from the workstation by the mail service executed on the mail server. .. The subscriber of the mail service has an individual mailbox (not shown) on the mail server, and the electronic mail addressed to the subscriber is delivered to the corresponding mailbox. User information (subscriber information) for using the mail service is registered in each directory server.

In the directory servers 13 and 16, "user name", "password", "address of mail server holding user's mailbox", etc. are registered as user information for using the mail service. These user information items are registered separately as real entries and virtual entries (neither is shown), and user information that does not require protocol conversion is registered in the real entries. On the other hand, the virtual entry does not have direct user information registered, and as a user information that requires protocol conversion, a mail gateway that can access user information held by directory servers connected to networks of different protocols. Information is registered. The directory servers 13 and 16 notify the address of the transfer destination mail server to the mail server to which the inquiry request is issued by using the real entry and the virtual entry.

The mail gateway 17 sets the protocol of the received electronic mail from TCP / IP to XNS, or from XNS.
It is a mail server that can convert TCP / IP and transfer protocol-converted e-mail to networks of different protocol systems (hereinafter referred to as mail server including mail gateway). Further, the mail gateway 17 can access the directory server connected to the converted protocol network, and inquires the user information such as the address of the mail server holding the mailbox of the recipient.

The integrated network 18 is composed of a local area network represented by Ethernet and / or a wide area network represented by X.25, or one of them.

Next, in the above electronic mail system,
Mail server 12 and directory server 13 for sending e-mail from workstation 11 of TCP / IP protocol to workstation 14 of XNS protocol
2 and the processing procedure of each device of the mail gateway 17.
~ It demonstrates by the flowchart of FIG.

FIG. 2 is a flow chart showing the processing procedure of the mail server 12. When the mail server 12 receives an electronic mail transmission request from the workstation 11, the mail server 12 determines whether the destination mailbox of the received electronic mail is in the same mail server (step 101). If the destination mailbox is in the same mail server, the electronic mail is delivered to the corresponding mailbox (step 102). If the destination mailbox is not in the same mail server, the directory server 13 is inquired about the address of the transfer destination mail server along with the address of the recipient (step 103).

Here, the directory server 13 to be described later
By the processing of, the address of the mail server of the transfer destination is notified. The mail server 12 is the directory server 13
The e-mail is transferred to the corresponding mail server by referring to the address returned from (step 104).

FIG. 3 is a flow chart showing the processing procedure of the directory server 13. Directory server 1
When receiving the inquiry request of the transfer destination mail server from the mail server 12, the third server 3 determines whether the user information of the recipient exists as an actual entry (step 20).
1). If the user information exists as a real entry, the mail server 12 is notified of the address of the mail server holding the recipient's mailbox (step 202). On the other hand, if the user information does not exist as a real entry, it is determined whether the user information exists as a virtual entry (step 203). If the user information does not exist as a virtual entry, the mail server 12 is notified that the corresponding address does not exist (step 204). If user information exists as a virtual entry, the protocol system indicated by the virtual entry (XNS protocol in this example)
Notifies the mail server 12 of the address of the mail gateway that can access the user information held by the directory server connected to this network (step 2).
05).

FIG. 4 is a flow chart showing the processing procedure of the mail gateway 17. Mail gateway 1
7 receives the transfer request of the email from the mail server 12, converts the protocol of the received email (step 301), and sends the received message to the directory server 16 belonging to the converted protocol (XNS protocol). Inquiry about the address of the mail server of the transfer destination together with the address of (step 302). Here, the address of the mail server of the transfer destination is notified by the processing of the directory server 16. Mail gateway 17
Refers to the address returned from the directory server 16 and transfers the electronic mail to the corresponding mail server (step 303).

As is apparent from the above embodiment, as the user information requiring protocol conversion, the address of the mail gateway that can interpret the address of the recipient is registered in the virtual entry in the directory server, and the mail server makes an inquiry request. If it is determined that the user information of the recipient who has the information is in the virtual entry, the mail server is notified of the address of the gateway that can access the user information of the directory server connected to the network of a different protocol system. E-mail sent to the recipient of the protocol system will be automatically sent from the mail server to the corresponding mail gateway, and the user can record or recognize the address of the mail gateway that can interpret the address of the recipient. No need to leave.

Next, an embodiment of the electronic mail system according to the second invention will be described with reference to FIGS. The entire configuration of the electronic mail system of this embodiment is the same as that of the electronic mail system of FIG. 1 described above, and only the configuration of the mail gateway is different. In this embodiment, the mail gateway 17 of FIG. 1 is replaced with a mail gateway 21 described below.

FIG. 5 is a block diagram showing the functional configuration of the mail gateway 21 used in the electronic mail system according to the second invention. The mail gateway 21 includes a data transmission / reception unit 22 that transmits / receives data according to the TCP / IP protocol and the XNS protocol, a protocol conversion unit 23 that converts the protocol of the data received by the data transmission / reception unit 22, and a user who is permitted to transmit. It is composed of a transmission-permitted person database 24, which is a storage means for registering the e-mail address of, and a search section 25 for searching the transmission-permitted person's mail address registered in the transmission-permitted person database 24.

FIG. 6 shows an example of a registration file stored in the authorized sender database 24. Username 3 as the email address of the user who is allowed to send
1, the department name 32, and the company name 33 are provided, and the system administrator registers by writing the mail address of the user who is permitted to send in the registration file as shown in FIG. The registered content can be rewritten arbitrarily, and each item can be changed appropriately. When the mail gateway 21 starts up, the contents of the registration file are cached in a memory (not shown) to speed up the search process.

Next, in the above electronic mail system,
FIG. 7 shows a processing procedure of the mail gateway 21 when an electronic mail is sent from the workstation 11 of the TCP / IP protocol to the workstation 14 of the XNS protocol.
The flowchart will be described.

First, when the data transmitting / receiving unit 22 of the mail gateway 21 receives a transfer request for an electronic mail (step 401), the searching unit 25 causes the sender's mail address of the received electronic mail to be stored in the authorized sender database 24. Search (step 402). Then, it is determined whether or not the sender's mail address exists in the registration file of the authorized sender database 24 (step 4).
03). If the sender's mail address does not exist in the registration file, an error message is added to the sender and returned to the sender (step 403). If the sender's mail address exists in the registration file, protocol conversion is performed (step 404) and the mail server having the recipient's mailbox (in this example, the mail server 1
5) (step 405).

In the electronic mail system according to the second aspect of the present invention, the mail address of the user who is permitted to send is registered in the database, and the mail address of the sender of the received electronic mail exists in the database. Since only the e-mails are forwarded, only the e-mails of the users who are permitted to send the e-mails are forwarded to the recipients, and the use of the e-mails by an unspecified number of users can be restricted. In the above-mentioned two embodiments, TCP / IP and XNS are used as the protocol of the network.
Although the example using is described, other protocols may be used as long as they have equivalent functions.

[0031]

As described above, in the electronic mail system according to the first aspect of the present invention, user information held by directory servers connected to networks of different protocol systems is accessed as user information requiring protocol conversion. A mail gateway address that can be registered is registered as a virtual entry in the directory server, and when the user information of the mail recipient exists in the virtual entry, the mail gateway address is notified to the mail server. The email sent to the recipient of will be automatically sent from the mail server to the corresponding mail gateway. Therefore, the user does not need to record or recognize the address of the mail gateway that can interpret the address of the recipient, which can reduce the burden on the sender when sending an e-mail to the recipients of different protocol systems. it can. Moreover, since it is only necessary to send the e-mail to a nearby mail server, it is possible to minimize the communication time even when the mail gateway is located in a remote place.

Further, in the electronic mail system according to the second aspect of the present invention, there are provided storage means for registering a mail address of a specific user who is permitted to send, and searching means for searching the mail address registered in the storage means. Since the electronic mail is transferred only when the mail address of the sender of the received electronic mail exists in the database, only the electronic mail of the user who is permitted to send the mail is transferred to the recipient. Therefore, by registering the users who can use the e-mail at the gateway, it is possible to restrict the use of the e-mail by an unspecified number of users and grasp the users. Further, by limiting the electronic mail users, the rules and restrictions for network operation are complied with, so that the system can be operated efficiently.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of an electronic mail system according to a first invention.

FIG. 2 is a flowchart showing a processing procedure of a mail server when sending an electronic mail.

FIG. 3 is a flowchart showing a processing procedure of a directory server when sending an electronic mail.

FIG. 4 is a flowchart showing a processing procedure of a mail gateway when sending an electronic mail.

FIG. 5 is a block diagram showing a functional configuration of a mail gateway used in the electronic mail system according to the second invention.

FIG. 6 is an explanatory diagram showing an example of a registration file stored in a transmission authorized person database.

FIG. 7 is a flowchart showing a processing procedure of a mail gateway when sending an electronic mail.

[Explanation of symbols]

11, 14 ... Workstation, 12, 15 ... Mail server, 13, 16 ... Directory server, 17, 21
… Mail gateway, 18… Integrated network, 22
... data transmission / reception section, 23 ... protocol conversion section, 24 ... transmission permitted person database, 25 ... search section

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location H04L 12/58 29/06 8020-5K H04L 13/00 305 B

Claims (2)

[Claims] 1. A mail gateway that transfers e-mails using different communication protocols by protocol conversion, a network mutually connected via the mail gateway, and a plurality of networks connected to the network for sending and receiving e-mails. In the e-mail system including the terminal device and the directory server in which the user information for using the e-mail service is registered, in the directory server, user information that does not require protocol conversion is registered as an actual entry, and protocol conversion is performed. Required user information as a virtual entry,
An electronic mail system characterized by registering information of a mail gateway that can access user information held by a directory server connected to a corresponding protocol network. 2. A mail gateway that transfers e-mails using different communication protocols by protocol conversion, a network mutually connected via the mail gateway, and a plurality of networks connected to the network for sending and receiving e-mails. In the electronic mail system including the terminal device of No. 1 and the directory server in which the user information for using the electronic mail service is registered, a storage unit in which the mail address of the sender is registered, and a search for searching the mail address in the storage unit Means for providing a protocol conversion for an electronic mail using a different protocol, the searching means searches the e-mail sender's mail address to see if the mail address exists in the storage means. The email address is the email address of the sender An electronic mail system which transfers the electronic mail only when the electronic mail is registered in the storage means.