JP2002319974A - Communication system and communication apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication system that shortens the time of transmission confirmation up to a reply by more efficiently performing the reply of e-mail for transmission confirmation. SOLUTION: A mail server 11 attaches a transmission confirmation request by a DSN to e-mail addressed to a domain including a mail server 12 and transmits the e-mail to the mail server 12 with an SMTP(simple mail transfer protocol). In such a case, the mail server 11 transmits a transmission right inversion command to the mail server 12 after transmitting the transmission confirmation request and the e-mail with by the DSN. The mail server 12 receives the transmission right inversion command and returns e-mail of transmission confirmation about the previously received e-mail while maintaining the session. Thus, it is possible to shorten the time between e-mail transfer and the return of transmission confirmation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a communication system for transferring electronic mail between a transmitting device and a receiving device, and a communication device used in the communication system.

[0002]

2. Description of the Related Art In a communication system for transferring an e-mail using a network such as the Internet, it is necessary to check whether the e-mail has reached a destination.
DSN (Delivery Status Notification) or MDN (Message Disposition
Notification, or the like, can request delivery confirmation at the time of sending an e-mail. For example, in DSN, when a mail server of a domain to which a destination client belongs receives an e-mail, the mail server transmits a delivery confirmation e-mail to the destination specified at the time of the delivery confirmation request. Also, in the MDN, when a destination device such as a client or a server of a destination receives an e-mail, the receiving device transmits an e-mail for a delivery confirmation to a destination specified at the time of a delivery confirmation request.

[0003] In the exchange of e-mail accompanied by such delivery confirmation, SMTP (Simple Mail Tr) is used.
transfer an e-mail with a delivery confirmation request, and once SMT
After closing the P session, a new SMTP session was opened and a delivery confirmation e-mail was sent.
For this reason, there is a problem that it takes time to transmit the delivery confirmation e-mail.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has been made in consideration of the above circumstances. It is an object of the present invention to provide a communication device suitable for use in such a communication system.

[0005]

According to the present invention, in a communication system for transferring an electronic mail between a transmitting apparatus and a receiving apparatus, the transmitting apparatus transmits the electronic mail with a delivery confirmation request to the receiving apparatus. After transmitting the transmission right inversion command, the receiving device transmits the transmission confirmation of the received e-mail when the transmission right inversion command is received after receiving the e-mail with the delivery confirmation request. It is a feature.

Further, according to the present invention, it is known that, in a communication device for transferring an e-mail to a receiving device, the receiving device returns a acknowledgment when the e-mail with the delivery confirmation request is transmitted. In this case, the transmission right inversion command is transmitted after transmitting the e-mail with the transmission confirmation request, and the transmission confirmation is received from the receiving side device.

Further, the present invention provides a communication apparatus for receiving an e-mail sent from a transmitting device, comprising: receiving a transmission right inversion command after receiving an e-mail with a delivery confirmation request from the transmitting device; The transmission confirmation of the e-mail is transmitted.

[0008] As described above, after transmitting the e-mail with the delivery confirmation request, the transmission right inversion command is transmitted, and the delivery confirmation request can be returned without disconnecting the session. Therefore, it is possible to shorten the time until the reply of the delivery confirmation as compared with the case where the session is newly established and the delivery confirmation is transmitted as in the related art, and it is possible to efficiently transmit the delivery confirmation e-mail. .

[0009]

FIG. 1 is a block diagram showing an embodiment of a communication system according to the present invention. In the figure, 11 and 12 are mail servers, and 13 is a client. The mail server 11 and the mail server 12 can transfer e-mail to each other by SMTP. Here, it is assumed that the electronic mail is transferred from the mail server 11 to the mail server 12.

The mail server 11 receives an e-mail from a client in the same domain or another mail server, and distributes the received e-mail or the e-mail from which the own device is a source. For example, mail server 12
The e-mail addressed to the domain to which the e-mail belongs belongs to the mail server 12.

In some cases, the transmitted e-mail is accompanied by a request for delivery confirmation. Alternatively, a delivery confirmation request can be added to the e-mail when the e-mail is transferred.
For example, when transferring an e-mail with a delivery confirmation request by DSN, when the transfer destination is a mail server in a domain including a client of the destination of the e-mail,
It is possible to receive a delivery confirmation directly from the transfer destination mail server. In such a case, the mail server 11
Sends the e-mail with the delivery confirmation request to the mail server, sends a transmission right inversion command, and receives the delivery confirmation e-mail from the transfer destination mail server with the session continued. As a result, it is possible to reduce the time from when the e-mail with the delivery confirmation request is transferred to when the delivery confirmation for the e-mail is transmitted.

The reason why the transmission right inversion command is transmitted after the transmission of the electronic mail and the delivery confirmation is received by the DSN is that the transfer destination of the electronic mail includes the client of the destination of the electronic mail as described above. It is a mail server in the domain. Whether or not the transfer destination of the e-mail is such a mail server is determined by, for example, DNS (Do
main name system), the IP address of the transfer destination mail server is registered in advance, and the registered IP address of the mail server is registered.
It can be determined from the P address.

Further, even if the transfer destination of the e-mail is a mail server in the domain including the client of the destination of the e-mail, when the transmission right inversion command is sent,
It is not known whether or not a delivery confirmation will be returned by the SN. In order to determine this, it is determined whether the IP address of the mail server of the transfer destination is registered in advance as described above, or by referring to information of a specific field in the e-mail, or If the own device is the transmission source, the determination can be made by receiving an instruction from the user of the own device.

The mail server 12 has the same function as the mail server 11, and receives e-mail from another mail server such as the mail server 11 or a client and distributes the e-mail. For example, an e-mail addressed to the client 13 is distributed to the client 13 according to a protocol such as POP3 in response to an e-mail retrieval request from the client 13.

When an e-mail addressed to the own device or a domain including the own device is received, and a delivery confirmation request is added to the e-mail, an e-mail for a delivery confirmation of the received e-mail is transmitted. . When the transmission right inversion command is received after receiving the e-mail, if the e-mail is addressed to the own device or to a domain including the own device, the transmission confirmation e-mail is transmitted without changing the session. . As a result, the time from reception of an e-mail to transmission of an e-mail for delivery confirmation can be reduced.

When the transmission right inversion command is received after the transfer of the e-mail with the delivery confirmation request, whether or not to return the delivery confirmation is determined by, for example, registering the IP address of the partner in advance and checking whether the registered partner is registered. The determination can be made based on whether the answer is NO. Alternatively, when the transmission right reversal command is received, an e-mail for the transmission confirmation may be sent if the transmission confirmation is requested regardless of the other party.

FIG. 2 is an explanatory diagram of a specific example of a communication procedure in an embodiment of the communication system of the present invention. Here, an example is shown in which electronic mail with a DSN request addressed from the mail server 11 to a client in the domain of the mail server 12 is transferred by SMTP. Note that the domain name of the mail server 11 is “tmA.NE”.
T ”and the domain name of the mail server 12 as“ tmB. NE
T. The source address of the electronic mail is “ME@tmA.T”. NET ”and the destination address is“ Y
OU @ tmB. NET ”.

First, in (1), the mail server 11 establishes a TCP connection with the mail server 12 using the IP address of the mail server 12. If the TCP connection is successful, the Service Ready of the SMTP response (No. 220) is returned from the mail server 12 in (2). In step (3), the mail server 11 sends the domain name “tm” of the mail server 11 by using the SMTP command EHLO.
A. NET ". In response to this, the mail server 12 sends the domain name of the mail server 12" tmB. NET ”. At the same time, in (5), it is notified that there is DSN capability by the SMTP response (No. 250).

Subsequently, in (6), the source of the e-mail is "ME@tmA.NET" by the SMTP command, and in (8), the destination is "YOU @ t".
mB. NET ", each mail server 1
Notify 2. At this time, following each command,
Transfers various information about DSN. In addition, if the mail server 12 can receive these SMTP commands normally (7) and (9), it returns OK in the SMTP response (number 250).

Then, in (10), the mail server 11
Sends the SMTP command DATA from the mail server 1
From 2 to (11), end with <CRLF as a terminator by an SMTP response (number 354)
>. After <CRLF> is returned, in (12), the actual e-mail data is transmitted. Finally, in (13), <CRLF>. <CRLF
Send>. If the mail server 12 can receive the mail normally, it returns OK in the SMTP response (No. 250) in (14), and the transfer of a series of e-mails ends.

At this time, the mail server 11 sends the SMTP command TURN to the mail server 12 at (15). This command is a transmission right inversion command and transfers the transmission right to the mail server 12 while maintaining the session. The mail server 12 responds to the SMTP command TURN in (16) with the SMT
OK is returned by P response (No. 250).

This time, since the mail server 11 is the receiving side, a ServiceReady is sent to the mail server 12 by means of an SMTP response (number 220) at (17) to inform that the reception is possible. Hereinafter, the e-mail of the delivery confirmation by the DSN is sent from the mail server 12 to the mail server 11 in the same procedure as the above-described e-mail transfer.
Will be forwarded to That is, the mail server 12
Notifies the domain name "tmB.NET" of the mail server 12 by the SMTP command EHLO in (18). In response, the mail server 11 sends an SMTP response (number 250) at (19).
Is notified of the domain name "tmA.NET".

Subsequently, in (20), the sender of the e-mail (e-mail for delivery confirmation by DSN) is “YOU@tmB.NET” by the SMTP command, and the destination is “ME @ tmA” in (22). .N
ET "is notified to the mail server 11. If the mail server 11 can normally receive these SMTP commands, (21) and (23)
Returns OK by SMTP response (No. 250).

In (24), the mail server 12
Sends the SMTP command DATA from the mail server 1
From 1 to (25), an end response <CRLF as a terminator by an SMTP response (number 354)
>. After the <CRLF> is returned, in (26), the mail server 12 transmits the e-mail data of the delivery confirmation of the DSN. Finally, in (27), <CRLF>. <CRLF> is transmitted. If the mail server 11 can receive the message normally, the mail server 11 proceeds to step (28).
OK is returned by the MTP response (No. 250), and the transfer of the DSN delivery confirmation e-mail is completed.

Finally, to end the session, (2
In 9), the mail server 12 sends the SMTP command QUA
Sends IT and mail server 11 sends SM
Service crossi of TP response (number 221)
An ng transmission channel is sent, and the TCP connection is disconnected at (31) to end the communication.

In this way, when the e-mail with the delivery confirmation request is transmitted by the DSN, the e-mail of the delivery confirmation can be received by continuing the session at that time. Therefore, compared to the case where the e-mail of the delivery confirmation is received by another session as before,
It is possible to receive a delivery confirmation e-mail in a much shorter time.

In the above example, the TURN of the SMTP command is used as the transmission right inversion command. However, the present invention is not limited to this, and any command can be used as long as the command can be switched between the transmission side and the reception side. Good. For example, between devices that can mutually understand non-standard commands, control may be performed so that the transmission right is passed to the other party using the non-standard commands.

FIG. 3 is a configuration diagram showing another embodiment of the communication system of the present invention. In the figure, the same parts as those in FIG. In the example shown in FIG. 3, the mail server 12 is a destination (recipient) of an e-mail.
Is shown. In this case, the mail server 12
Can return a delivery confirmation by DSN as in the above-described embodiment, and can also return a delivery confirmation for an electronic mail with a delivery confirmation request by MDN addressed to the own device.

FIG. 4 is an explanatory diagram of a specific example of a communication procedure in another embodiment of the communication system of the present invention, and FIG.
FIG. 4 is an explanatory diagram of a main part of an e-mail with a delivery confirmation request by a DN. Here, an example is shown in which an electronic mail with an MDN request addressed from the mail server 11 to the mail server 12 is transferred by SMTP. The domain name of the mail server 11 is “tmA.NET”, the domain name of the mail server 12 is “tmB.NET”, and the e-mail address of the mail server 12 is “YOU@tmB.NE”.
T. Also, the e-mail address of the e-mail sender is “ME@tmA.T”. NET ". The source of this e-mail does not need to be the mail server 11, but may be another client.

The communication procedure shown in FIG. 4 is almost the same except that information for DSN is not transmitted in the procedures (6) and (8) in FIG. In the case of MDN, a delivery confirmation request is described in the e-mail as shown in FIG. FIG. 5 shows an example of a header portion of an e-mail, and the sixth line (line with an arrow) indicates “Disposition-Notif”.
ication-To: ”, which is described subsequently as“ ME @ tmA. It is instructed to return an e-mail confirming delivery to NET ".

The mail server 12 knows that it is an electronic mail addressed to itself when the destination is notified in (8) in FIG. When the data of the e-mail is received by (12), the contents are analyzed, and the delivery confirmation by the MDN is sent to the e-mail address “ME@tmA.N”.
ET ".

When the electronic mail transfer procedure up to (14) is completed as described with reference to FIG. 2, in (15), the mail server 11 transmits an SMTP command TURN as a transmission right inversion command, here as an example. . Of course, also in this case, the transmission right inversion command is TUR.
Not limited to the N command, any command that performs the same function can be used.

The mail server 12 responds to the TURN command from the mail server 11 by using the SM in (16).
OK is returned by the TP response (No. 250). Then, after receiving the ServiceReady from the mail server 11 in the SMTP response (No. 220) in (17), the e-mail of the delivery confirmation by MDN is sent to the e-mail address "ME @" by the procedures of (18) to (28).
tmA. NET ”.

Finally, to end the session, (2
In 9), the mail server 12 sends the SMTP command QUA
Sends IT and mail server 11 sends SM
Service crossi of TP response (number 221)
An ng transmission channel is sent, and the TCP connection is disconnected at (31) to end the communication.

In this way, when an e-mail with a delivery confirmation request is transferred by the MDN, the session at that time can be continued and an e-mail for delivery confirmation can be received. Therefore, compared to the case where the e-mail of the delivery confirmation is received by another session as before,
It is possible to receive a delivery confirmation e-mail in a much shorter time.

In the above two embodiments, the SMT
The description has been made on the premise that communication between mail servers is performed by P. However, any other protocol can be implemented in the same manner as long as it is a protocol that can transmit and reverse the transmission right inversion command by transmitting a transmission right inversion command.

FIG. 6 is a block diagram showing an application example of the communication system of the present invention. In the figure, 21 and 27 are facsimile machines, 22 and 26 are telephone lines, 23 and 25 are Internet facsimile machines, and 24 is the Internet. The Internet facsimile machine 23 and the Internet facsimile machine 25 are both Internet 2
4 is a server-type network device connected to the server 4. Each of them has the same function as the mail servers 11 and 12 in the embodiment of the communication system described above.

For example, when transmitting an image from the facsimile apparatus 21 to the facsimile apparatus 27, the telephone line 22
A line is connected to the Internet facsimile machine 23 via the Internet. Then, it notifies the domain or the e-mail address of the Internet facsimile device 25 together with the telephone number of the facsimile device 27 and sends the image to be transmitted.

The Internet facsimile machine 23 converts the image received from the facsimile machine 21 into an electronic mail and transfers it to the Internet facsimile machine 25 through the Internet 24 together with the received facsimile machine 27 telephone number. The e-mail address at this time is the e-mail address of the Internet facsimile apparatus 25 itself, or the e-mail address composed of the domain name of the Internet facsimile apparatus 25 and the telephone number of the facsimile apparatus 27. Various forms are conceivable. In any case, an address at which the Internet facsimile machine 25 can receive an electronic mail is designated.

At this time, information requesting delivery confirmation can be added to the e-mail to be transferred to the Internet facsimile machine 25. The delivery confirmation request in this case may be DSN or MDN. In this case, the Internet facsimile device 25
Is the destination (recipient) of the email, so the MD
Even if it is N, the e-mail of the delivery confirmation is returned from the Internet facsimile machine 25. The addition of such a delivery confirmation request is performed, for example, by using the facsimile device 21.
Or automatically by the Internet facsimile machine 23.

As described in each of the above embodiments, after transmitting the electronic mail from the Internet facsimile machine 23, the transmission right inversion command is transmitted. The Internet facsimile machine 25 having received this transmits an e-mail for delivery confirmation by the DSN or MDN to the Internet facsimile machine 23.

The Internet facsimile machine 2
5 is set as one of various setting items at the time of transmission in the facsimile device 21, for example, and the Internet facsimile device 23 is set at the time of transmission.
Can be configured to communicate. In the facsimile machine 21, such setting items can be easily instructed by registering them in advance with one-touch keys or shortcut keys. Alternatively, in the Internet facsimile machine 23, a list of destinations that return the delivery confirmation e-mail by sending the transmission right inversion command is registered, and the transmission right inversion command is sent in the case of the registered destination. Can be Of course, it is possible to know the other party's ability in other ways.

The Internet facsimile machine 23, which has received the delivery confirmation e-mail, can transmit a facsimile image including the contents of the delivery confirmation to the facsimile machine 21, for example, in a log or according to a request or as a service. . As described above, when an image is transmitted from the Internet facsimile machine 23, a delivery confirmation can be immediately received from the Internet facsimile machine 25, and the time from image transmission to receipt of the delivery confirmation can be reduced.

Internet facsimile machine 2 which has received an electronic mail including an image addressed to facsimile machine 27
In step 5, the telephone number of the facsimile machine 27 is obtained from the contents, and the facsimile
Facsimile transmission of the image. Thus, the image transmitted from the facsimile machine 21 reaches the facsimile machine 27 via the Internet 24. Fees vary according to distance in telephone lines, but charges are not related to distance in the Internet. Therefore, in long-distance image transmission, transmission via the Internet may be possible at lower cost.

In the example shown in FIG. 6, an example is shown in which communication is performed between the Internet facsimile machines 23 and 25 and a communication terminal such as a facsimile machine via a telephone line. However, the present invention is not limited to this. For example, facsimile communication may be performed from or to a terminal device connected to the Internet facsimile device via a LAN or the like. Of course, facsimile transmission from the Internet facsimile apparatus and facsimile reception by the Internet facsimile apparatus are also possible.

[0046]

As is apparent from the above description, according to the present invention, the delivery confirmation can be returned within one SMTP session, and therefore, from the transfer of the e-mail to the reception of the delivery confirmation for the e-mail. There is an effect that the time can be reduced and the delivery confirmation reply can be made more efficiently.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating an embodiment of a communication system according to the present invention.

FIG. 2 is an explanatory diagram of a specific example of a communication procedure in an embodiment of the communication system of the present invention.

FIG. 3 is a configuration diagram showing another embodiment of the communication system of the present invention.

FIG. 4 is an explanatory diagram of a specific example of a communication procedure in another embodiment of the communication system of the present invention.

FIG. 5 is an explanatory diagram of a main part of an electronic mail with a delivery confirmation request by MDN.

FIG. 6 is a block diagram showing an application example of the communication system of the present invention.

[Explanation of symbols]

11, 12: mail server, 13: client, 2
1, 27: facsimile machine, 22, 26: telephone line,
23, 25 ... Internet facsimile machine, 24 ...
the Internet.

Claims (3)

[Claims] 1. A communication system for transferring an electronic mail between a transmitting device and a receiving device, wherein the transmitting device transmits an e-mail with a delivery confirmation request to the receiving device, and then transmits a transmission right inversion command to the receiving device. The receiving side device transmits an acknowledgment of the received e-mail when receiving the transmission right inversion command after receiving the e-mail with the acknowledgment request. 2. A communication device for transferring an e-mail to a receiving device, wherein when the receiving device returns an acknowledgment when transmitting the e-mail with the delivery confirmation request, A communication device, comprising: transmitting a transmission right inversion command after transmitting the e-mail with the delivery confirmation request; and receiving a delivery confirmation from the receiving device. 3. A communication device for receiving an e-mail sent from a transmitting device, comprising: receiving a transmission right inversion command after receiving an e-mail with a delivery confirmation request from the transmitting device; A communication device for transmitting an acknowledgment of the communication device.