JP2017111640A - Information processor, mail sending/receiving system and mail sending/receiving method, and computer program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an information processor etc. capable of reliably sending/receiving email without requiring any additional device.SOLUTION: An information processor 10 includes: a port determination section 13 that determines a port number which is used when transmitting and receiving an email to a mail server; and a control section 15 that makes an access to a mail server using the port number determined by the port determination section 13.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an information processing apparatus, a mail transmission / reception system, a mail transmission / reception method, and a computer program.

  As mail protocols generally used in electronic mail, there are SMTP (Simple Mail Transfer Protocol) and POP (Post Office Protocol). When sending mail, the default port 25 of SMTP is used as the mail server standby port. When a mail is received, the POP default port 110 is used as the mail server standby port. For this reason, if a third party can know that the port number 110 is being used, it can be assumed that mail communication is being performed. In that case, the third party can easily confirm the content of the mail being sent and received by analyzing the communication content.

  In order to avoid such an event, there is a method of changing the port number so as not to be understood as mail communication. However, manually changing the port number takes time and effort from the user. In order to automate the change, there is also a method of notifying the port number to be changed on the protocol, but this method is like notifying the port to be used by a third party, which may cause a problem. There is sex.

  Here, as related technologies, for example, there are the following patent documents.

  Patent Document 1 discloses an e-mail transmission method that divides a mail transmission content into a plurality of pieces and changes the order of transmission.

  Patent Document 2 discloses a message transmission device that divides a transmission message and a dummy message into a plurality of pieces, rearranges them, and transmits them.

  Patent Document 3 discloses an electronic mail system that encrypts an electronic mail and divides the electronic mail into a plurality of parts, and delivers the divided divided encrypted mails to the receiving side via different mail servers.

JP 2003-044411 A JP 2002-040939 A JP 2004-355089 A

  However, the techniques proposed in Patent Documents 1 to 3 do not particularly take into account the standby port of the mail server.

  Furthermore, since the technique proposed in Patent Document 3 requires a plurality of mail servers, it is costly.

  SUMMARY OF THE INVENTION Accordingly, it is a primary object of the present invention to provide an information processing apparatus and the like that can transmit and receive electronic mail with higher reliability without requiring an additional apparatus.

  In order to achieve the above object, an information processing apparatus according to an aspect of the present invention includes the following arrangement.

That is, an information processing device according to one embodiment of the present invention is provided.
Port determination means for determining a port number to be used when sending and receiving to a mail server;
Control means for accessing the mail server using the port number determined by the port determining means.

An email transmission / reception system according to an aspect of the present invention that achieves the same object
The mail transmitted from the first information processing apparatus is passed through the mail server,
Received by the second information processing apparatus.

An email transmission / reception method according to an aspect of the present invention that achieves the same object
A port number to be used for transmission and reception to the mail server is determined, and the mail server is accessed using the port number.

  Furthermore, the object is to read the information processing apparatus, the mail transmission / reception system, or the mail transmission / reception method having the above-described configuration by a computer, a computer program storing the computer program, and computer-readable This is also achieved by a storage medium.

  According to the present invention described above, there is an effect that it is possible to send and receive electronic mail with higher reliability without requiring an additional device.

It is a block diagram which shows the structure of the information processing apparatus which concerns on the 1st Embodiment of this invention. It is a block diagram which shows the structure of the mail transmission / reception system which concerns on the 2nd Embodiment of this invention. It is a figure explaining the mail data produced by the mail preparation part of the data transmitter in the mail transmission / reception system which concerns on the 2nd Embodiment of this invention. It is a figure explaining the mail data produced by the mail preparation part of the data receiver in the mail transmission / reception system which concerns on the 2nd Embodiment of this invention. It is a flowchart explaining the process in the analysis part in the data receiver of the mail transmission / reception system which concerns on the 2nd Embodiment of this invention. It is a flowchart explaining the process in the analysis part in the data transmitter of the mail transmission / reception system which concerns on the 2nd Embodiment of this invention. It is a flowchart explaining the process in the port determination part in the data transmitter of the mail transmission / reception system which concerns on the 2nd Embodiment of this invention. It is a flowchart explaining the process in the port determination part in the data receiver of the mail transmission / reception system which concerns on the 2nd Embodiment of this invention. It is a figure which illustrates illustartively the hardware constitutions of the computer (information processing apparatus) which can implement | achieve the 1st and 2nd embodiment of this invention.

  Next, embodiments of the present invention will be described in detail with reference to the drawings.

<First Embodiment>
FIG. 1 is a block diagram showing the configuration of the information processing apparatus according to the first embodiment of the present invention.

  The information processing apparatus 10 according to the present embodiment includes a port determination unit 13 and a control unit 15.

  The port determining unit 13 determines a port number to be used when transmitting and receiving to a mail server (not shown). For example, the port determination unit 13 may determine the SMTP default port 25 as the mail server standby port, or may determine the port numbers of other ports. The port determination unit 13 may determine the POP default port number 110 as a standby port of the mail server when receiving mail, or may determine the port numbers of other ports.

  The control unit 15 accesses the mail server using the port number determined by the port determination unit 13.

  As described above, the first embodiment has an effect that it is possible to send and receive e-mail with higher reliability without requiring an additional device.

  The reason is that, in the information processing apparatus 10 according to the present embodiment, the port determination unit 13 determines which port of the mail server to use when transmitting or receiving mail. As a result, the port used for mail transmission / reception is not fixed, making it difficult for the contents of the electronic mail to be stolen.

<Second Embodiment>
Next, a second embodiment based on the information processing apparatus 10 according to the first embodiment described above will be described. FIG. 2 is a block diagram showing a configuration of a mail transmission / reception system according to the second embodiment of the present invention. However, the configuration shown in FIG. 2 is an example, and the present invention is not limited to the mail transmission / reception system shown in FIG.

  The mail transmission / reception system according to the present embodiment includes a data transmission device 100, a data reception device 200, and a mail server 300. As shown in FIG. 2, the data transmission device 100, the data reception device 200, and the mail server 300 are communicably connected via a LAN (Local Area Network) 400. The data transmitting apparatus 100 and the data receiving apparatus 200 are other examples of the information processing apparatus according to the first embodiment.

  The data transmission device 100 transmits mail data to the mail server 300. The data transmission device 100 is a first information processing device capable of transmitting mail data.

  The data receiving device 200 receives the mail data from the mail server 300. The data receiving device 200 is a second information processing device capable of receiving mail data.

  The data transmission device 100 includes a data creation unit 110, a data division unit 120, a port determination unit 130, a mail creation unit 140, a control unit 150, an analysis unit 160, and a storage unit 170. Hereinafter, the mail data may be simply referred to as mail.

  The data creation unit 110 creates transmission target data of the data transmission device 100. The transmission target data represents data to be transmitted by mail.

  The data dividing unit 120 divides the transmission target data created by the data creating unit 110.

  The port determining unit 130 determines a TCP / IP (Transmission Control Protocol / Internet Protocol) port number used when transmitting and receiving mail data to the mail server 300.

  The mail creation unit 140 creates mail data that is actually transmitted to the mail server 300.

  The control unit 150 controls transmission of mail data to the mail server 300 and reception of mail data from the mail server 300 using the port number determined by the port determination unit 130.

  The analysis unit 160 analyzes mail data received by the data transmission device 100.

  The storage unit 170 stores divided data 1701, transmission source port data 1702, reception source port data 1703, transmission source phrases 1704, reception source phrases 1705, and transmission source message IDs (IDentification) 1706.

  The divided data 1701 is divided data after being divided by the data dividing unit 120.

  The transmission source port data 1702 is a port number used when mail data is transmitted to the mail server 300.

  The reception source port data 1703 is a port number used when receiving mail data from the mail server 300.

  The transmission source phrase 1704 is an identifier added by the mail creation unit 140 to mail data to be transmitted by the data transmission apparatus 100.

  The reception source phrase 1705 is an identifier added by the transmission source of the mail data (here, the data reception device 200) included in the mail data received by the data transmission device 100.

  The transmission source message ID 1706 is an identifier added to mail data to be transmitted in order to identify individual mails.

  Data receiving apparatus 200 includes a data combining unit 220, a port determining unit 230, a mail creating unit 240, a control unit 250, an analysis unit 260, and a storage unit 270.

  The data combining unit 220 combines a plurality of pieces of divided data 2701 included in the mail data transmitted after being divided by the data dividing unit 120 of the data transmitting apparatus 100, and restores the transmission target data before the division.

  The port determination unit 230 determines a TCP / IP port number used when transmitting and receiving to the mail server 300.

  The mail creation unit 240 creates a result notification (mail) for notifying the data transmission apparatus 100 that the mail data transmitted by the data transmission apparatus 100 has been received.

  The control unit 250 uses the port number determined by the port determination unit 230 to control transmission of mail to the mail server 300 and reception of mail from the mail server 300.

  The analysis unit 260 analyzes the mail data received by the data receiving apparatus 200 and extracts the divided data 2701, the transmission source message ID 2706, and the transmission source phrase 2704.

  The storage unit 270 stores the divided data 2701, the reception source port data 2702, the transmission source port data 2703, the transmission source phrase 2704, the reception source phrase 2705, the transmission source message ID 2706, and the transmission source mail address 2707. To do.

  The divided data 2701 is divided data extracted from the received mail data.

  The source port data 2702 is a port number used when receiving mail data from the mail server 300.

  The transmission source port data 2703 is a port number used when mail data is transmitted to the mail server 300.

  The transmission source phrase 2704 is an identifier added by the transmission source of the mail data (here, the data transmission apparatus 100) included in the mail data received by the data reception apparatus 200.

  The reception source phrase 2705 is an identifier added by the mail creation unit 240 to the result notification to be transmitted.

  The sender message ID 2706 is a message ID that is added to the received mail data and can uniquely identify the mail.

  The transmission source mail address 2707 is the mail address of the transmission source that transmitted the received mail data.

  Mail server 300 includes an SMTP processing unit 310 and a POP processing unit 320.

  The SMTP processing unit 310 transfers mail data transmitted from the data transmission device 100 and the data reception device 200 to the POP processing unit 320.

  The POP processing unit 320 receives mail reception from the data transmission device 100 and the data reception device 200.

  The SMTP processing unit 310 recognizes an odd number of ports 25 and 49152 to 65535 as a mail standby port. Further, the POP processing unit 320 recognizes even-numbered ports among the ports 110 and 49152 to 65535 as mail waiting ports. The mail data received by the SMTP processing unit 310 is transferred to the POP processing unit 320 and waits for mail reception. At this time, the standby port number in the POP processing unit 320 is a value obtained by adding “85” to the port number of the mail data received by the SMTP processing unit 310. In order to obtain the standby port number in this way, the mail data received by the SMTP processing unit 310 at the default port 25 is controlled so that the POP processing unit 320 waits for mail reception at the default port 110.

  The operation of the embodiment of the present invention will be described in detail.

  First, the data creation unit 110 of the data transmission device 100 creates transmission target data. Next, the data dividing unit 120 divides the transmission target data and stores it as the divided data 1701 in the storage unit 170. The data dividing unit 120 creates divided data by using a “Content-Type: message / partial” header described in RFC (Request For Comment) 2046 which is an Internet standard. Specifically, the data dividing unit 120 divides the transmission target data into an appropriate data size, and creates divided data 1701 by adding a header to each data. The header includes information indicating how many pieces of mail data are divided, information indicating what number of divided data the divided data is, and an identifier common to divided data created by dividing the same mail data Such information is included. These pieces of information are referred to when data is restored by the data combining unit 220.

Next, processing for transmitting the divided data 1701 will be described. The first divided data 1701 and the second and subsequent divided data 1701 are different in processing to be transmitted.
((Processing regarding the first divided data-from the data transmitting device to the data receiving device))
The port determination unit 130 of the data transmission device 100 determines a port number for connecting to the mail server 300. In the present embodiment, a mail added with a transmission source phrase and a reception source phrase is transmitted and received between the data transmission device 100 and the data reception device 200. The port determination unit 130 determines a port number based on these two phrases (transmission source phrase and reception source phrase). With reference to FIG. 7, the process of determining the port number will be described. FIG. 7 is a flowchart illustrating processing in the port determination unit 130 in the data transmission device 100 of the mail transmission / reception system according to the second embodiment of the present invention. First, the port determination unit 130 checks whether or not the transmission source phrase 1704 and the reception source phrase 1705 are recorded in the storage unit 170 (step S6001). When transmitting the first mail, since the mail has not been transmitted / received yet, the transmission source phrase 1704 and the reception source phrase 1705 are not stored in the storage unit 170 (“No” in step S6001). Therefore, the port determination unit 130 determines the source port data 1702 as port 25 that is normally used by SMTP, and the receiver port data 1703 as port 110 that is normally used by the POP (step S6007). .

  Next, the data transmitting apparatus 100 creates mail data by the mail creating unit 140.

  FIG. 3 is a diagram for explaining mail data created by the mail creation unit 140 of the data transmission device 100 in the mail transmission / reception system according to the second embodiment of the present invention. Referring to FIG. 3, the mail data includes an “X-Send-Phrase” header 2001, a “Disposition-Notification-To” header 2002, and divided data 1701.

  The “X-Send-Phrase” header 2001 is a header indicating a transmission source phrase, and is a header newly added in the present embodiment. In the “X-Send-Phrase” header 2001, a transmission source phrase is set after the “X-Send-Phrase:” character string. The transmission source phrase is a random alphanumeric character string of about a dozen characters. The transmission source phrase is an identifier of a different character string that is set every time mail data is created by the mail creation unit 140. Then, the mail creation unit 140 of the data transmission device 100 stores the transmission source phrase in the storage unit 170 as the transmission source phrase 1704.

  A “Disposition-Notification-To” header 2002 is a header used to request confirmation of whether or not mail has arrived. This is defined by RFC3798, which is an Internet standard. This is to request that a reply mail (reception confirmation) be returned by designating a reply mail address after the character string “Disposition-Notification-To:”. The mail creation unit 140 sets a sender mail address as a reply mail address.

  In addition, the mail creation unit 140 stores a character string that follows the “Message-Id” header of the created mail data (FIG. 3) in the storage unit 170 as a transmission source message ID 1706. The source message ID is determined by existing mail software. The transmission source message ID is, for example, a value obtained by adding date and time to the transmission source mail address, and a unique value is determined for each transmission.

  Next, the data transmitting apparatus 100 transmits mail to the mail server 300 using the SMTP protocol by the control unit 150. At this time, the data transmission device 100 transmits to the mail server 300 to the port number indicated by the transmission source port data 1702.

  The mail server 300 receives mail from the data transmission device 100. Since the mail including the first divided data is transmitted, the SMTP processing unit 310 receives the mail at the standby port 25. The received mail data is transferred to the POP processing unit 320 and waits for reception from the data receiving device 200. The mail server 300 stands by at a standby port number 110 obtained by adding “85” to the SMTP standby port number. In addition, the mail server 300 does not transfer the mail data when the data receiving apparatus 200 is connected to another standby port. Specifically, the mail server 300 returns zero (none) for mail data in response to a request for “LIST”, “STAT”, and “RETR”, which are POP protocol commands.

  Next, the port determining unit 230 of the data receiving apparatus 200 determines a port number for connecting to the mail server 300. Processing for determining a port number will be described with reference to FIG. FIG. 8 is a flowchart for explaining processing in the port determination unit 230 in the data receiving apparatus 200 of the mail transmission / reception system according to the second embodiment of the present invention. First, the port determination unit 230 checks whether or not the transmission source phrase 2704 and the reception source phrase 2705 are stored in the storage unit 270 (step S7001). When the first mail is received, the transmission source phrase 2704 and the reception source phrase 2705 are not stored in the storage unit 270 (“No” in step S7001). Therefore, the port determination unit 230 determines the transmission source port data 2703 as “25” and the reception source port data 2702 as “110” (step S7007).

  Next, the data receiving apparatus 200 connects to the mail server 300 via the control unit 250. The data receiving device 200 is connected to the 110th port determined by the port determining unit 230 and receives mail data.

  Then, the data reception device 200 transfers the received mail data to the analysis unit 260. With reference to FIG. 5, processing for analyzing mail data in the analysis unit 260 will be described. FIG. 5 is a flowchart for explaining processing in the analysis unit 260 in the data receiving apparatus 200 of the mail transmission / reception system according to the second embodiment of the present invention.

  First, the analysis unit 260 confirms whether or not the received mail data includes an “X-Send-Phrase” header (step S4001). If there is no header (“No” in step S4001), the analysis unit 260 determines that the mail data is not to be analyzed, and ends the analysis. If the header is present (“Yes” in step S4001), the analysis unit 260 extracts the character string that follows the header as a transmission source phrase and stores it in the storage unit 270 as the transmission source phrase 2704 (step S4002).

Next, the analysis unit 260 checks whether there is a “Disposition-Notification-To” header (step S4003). If there is no header (“No” in step S4003), the analysis unit 260 determines that the mail data is not the analysis target, and ends the analysis. If the header is present (“Yes” in step S4003), the analysis unit 260 extracts the character string that follows the header as a transmission source mail address, and stores it in the storage unit 270 as the transmission source mail address 2707 (step S4004). ). Then, the analysis unit 260 takes out the text of the mail and stores it as the divided data 2701 in the storage unit 270 (step S4005). Further, the analysis unit 260 stores the character string following the “Message-Id” header in the storage unit 270 as the transmission source message ID 2706 (step S4006).
((Process on the first divided data-from the data receiving device to the data transmitting device))
The data receiving device 200 creates mail data by the mail creating unit 240 in order to notify the data transmitting device 100 that the data has been received. The mail creation unit 240 creates mail data that is called MDN (Message Disposition Notification) defined by RFC3798, which is an Internet standard, and notifies the sender of reception.

  FIG. 4 is a diagram for explaining mail data created by the mail creation unit 240 of the data receiving apparatus 200 in the mail transmission / reception system according to the second embodiment of the present invention. The mail data includes an “X-Recv-Phrase” header 3001 and an “Original-Message-ID” 3002.

  The “X-Recv-Phrase” header 3001 is a header indicating a reception source phrase, and is a header newly added in the present embodiment. In the “X-Recv-Phrase” header 3001, a reception source phrase is set after the “X-Recv-Phrase:” character string. The reception source phrase is a random alphanumeric character string of about a dozen characters. The reception source phrase is an identifier of a different character string that is set every time mail data is created by the mail creation unit 240. Then, the mail creation unit 240 of the data reception device 200 stores the reception source phrase in the storage unit 270 as the reception source phrase 2705.

  The “Original-Message-ID” header 3002 indicates the source message ID added to the mail transmitted from the data transmitting apparatus 100. This is defined by RFC3798, which is an Internet standard, and can notify the data transmission apparatus 100 that mail data from the data transmission apparatus 100 has arrived. In the “Original-Message-ID” header 3002, a source message ID 2706 is added as a source message ID.

  Next, the port determining unit 230 of the data receiving apparatus 200 determines a port number for transmitting mail to the mail server 300. With reference to FIG. 8, a process for determining the port number will be described. First, the port determination unit 230 checks whether or not the transmission source phrase 2704 and the reception source phrase 2705 are stored in the storage unit 270 (step S7001). Since it is stored, the port determination unit 230 checks whether or not a new mail is received (step S7002). Since the mail is not received when the mail is transmitted (“No” in step S7002), the port determination unit 230 does not change the transmission source port data 2703 and the reception source port data 2702 stored in the storage unit 270 (step S7008). ).

  Next, the data receiving apparatus 200 connects to the mail server 300 via the control unit 250. The data reception device 200 connects to the port of the transmission source port data 2703 determined by the port determination unit 230 and transmits mail data. That is, the data receiving apparatus 200 connects to the 25th port of the mail server 300 and transmits mail data.

  The mail server 300 receives mail from the data receiving device 200. Since the process is related to the first divided data, the SMTP processing unit 310 receives the mail at the standby port 25. The received mail data is transferred to the POP processing unit 320 and waits for reception from the data transmission device 100. The POP processing unit 320 waits at the 110th standby port obtained by adding “85” to the SMTP standby port number.

  Next, the port determination unit 130 of the data transmission device 100 determines a port number for connecting to the mail server 300. Processing for determining a port number will be described with reference to FIG. First, the port determination unit 130 checks whether or not the transmission source phrase 1704 and the reception source phrase 1705 are stored in the storage unit 170 (step S6001). When the first mail is received, since the source phrase 1705 is not stored in the storage unit 170, the port determination unit 130 sets the source port data 1702 to “25” and the source port data 1703 to “110”. Determination is made (step S6007).

  Then, the data transmission apparatus 100 connects to the mail server 300 via the control unit 150. The data transmitting apparatus 100 is connected to the 110th port determined by the port determining unit 130 and receives mail data.

  Next, the data transmission device 100 transfers the received mail data to the analysis unit 160. With reference to FIG. 6, processing for analyzing mail data in the analysis unit 160 will be described. FIG. 6 is a flowchart illustrating processing in the analysis unit 160 in the data transmission device 100 of the mail transmission / reception system according to the second embodiment of the present invention.

  First, the analysis unit 160 confirms whether or not “Content-Type: multipart / report; report-type = disposition-notification” is included in the received mail data (step S5001). This is performed in order to confirm whether or not the mail data (result notification) is notified to the transmission source. If it is not a result notification (“No” in step S5001), the analysis unit 160 determines that the mail data is not the analysis target and ends the analysis. When it is a result notification (“Yes” in step S5001), the analysis unit 160 further checks whether or not there is an “Original-Message-ID” header (step S5002). When there is an “Original-Message-ID” header, the analysis unit 160 performs the following processing.

  That is, the analysis unit 160 takes out the character string that follows “Original-Message-ID:” and confirms whether or not it is the same as the source message ID 1706 stored in the storage unit 170 (step S5003). This is confirmation of whether or not the result notification corresponds to the mail data transmitted from the data transmission device 100. If they are different (“No” in step S5003), the analysis unit 160 determines that the mail data is not the analysis target, and ends the analysis. If they are the same (“Yes” in step S5003), the analysis unit 160 checks whether there is an “X-Recv-Phrase” header (step S5004). If the header is not present (“No” in step S5004), the analysis unit 160 determines that the mail data is not the analysis target and ends the analysis. If the header is present (“Yes” in step S5004), the analysis unit 160 extracts the character string that follows the header as a reception source phrase and stores it in the storage unit 170 as the reception source phrase 1705 (step S5005).

Up to this point, the processing related to the first divided data has been described.
((Processing on second divided data-from data transmitting device to data receiving device))
From here, the process regarding the 2nd division | segmentation data is demonstrated.

  The port determination unit 130 of the data transmission device 100 determines a port number for connecting to the mail server 300. Processing for determining a port number will be described with reference to FIG. First, the port determination unit 130 checks whether or not the transmission source phrase 1704 and the reception source phrase 1705 are stored in the storage unit 170 (step S6001). Since the transmission source phrase 1704 and the reception source phrase 1705 are already stored (“Yes” in step S6001), the port determination unit 130 confirms whether or not to newly transmit a mail (step S6002). Since the mail is transmitted (“Yes” in step S6002), the port determination unit 130 obtains a hash value from the transmission source phrase 1704 and the reception source phrase 1705 (step S6003). Next, the port determination unit 130 obtains a value that can be used as the port number based on the hash value (step S6004). Specifically, the port determination unit 130 converts the hash value into a number in the range of “49152” to “65535”. That is, the port determination unit 130 first obtains a remainder obtained by dividing the hash value by a value obtained by subtracting “49152” from “65535”. The port determining unit 130 uses the value (remainder) plus “49152” as the port number. However, when the port number becomes an even number, the port determination unit 130 adds “1” for setting the port number of the standby port in the SMTP processing unit 310 to an odd number. Next, the port determination unit 130 stores the value thus obtained in the storage unit 170 as the transmission source port data 1702 (step S6005). Then, the port determination unit 130 adds “85” to the transmission source port data 1702. The port determination unit 130 stores this in the storage unit 170 as reception source port data 1703 (step S6006). However, if “65535” is exceeded, the port determination unit 130 stores the value obtained by subtracting “65535” as the reception source port data 1703.

  Next, the mail creation unit 140 creates mail data in the same manner as described above.

  Then, the data transmitting apparatus 100 transmits a mail to the mail server 300 by the control unit 150 using the SMTP protocol. At this time, the data transmitting apparatus 100 transmits to the port number indicated by the source port data 1702.

  The mail server 300 receives mail from the data transmission device 100. The SMTP processing unit 310 receives mail at the port number indicated by the transmission source port data 1702. The received mail data is transferred to the POP processing unit 320 and waits for reception from the data receiving device 200. The mail server 300 stands by at the standby port number that is the number obtained by adding “85” to the SMTP standby port number.

  Next, the port determining unit 230 of the data receiving apparatus 200 determines a port number for connecting to the mail server 300. The process for determining the port number will be described with reference to FIG. First, the port determination unit 230 checks whether or not the transmission source phrase 2704 and the reception source phrase 2705 are stored in the storage unit 270 (step S7001). Since the transmission source phrase 2704 and the reception source phrase 2705 are stored in the storage unit 270 (“Yes” in step S7001), the port determination unit 230 checks whether or not a new mail is received (step S7002). ). Since the mail is received (“Yes” in step S7002), the port determination unit 230 obtains a hash value from the transmission source phrase 2704 and the reception source phrase 2705 (step S7003). Next, the port determination unit 230 obtains a value that can be used as the port number based on the hash value (step S7004). Specifically, the port number is obtained in the same manner as in step S6004 in FIG. Next, the port determination unit 230 stores the value obtained in this way as the transmission source port data 2703 in the storage unit 270 (step S7005). Then, the port determination unit 230 adds “85” to the transmission source port data 2703. The port determination unit 230 stores this in the storage unit 270 as the reception source port data 2702 (step S7006). However, if “65535” is exceeded, the port determination unit 230 stores the value obtained by subtracting “65535” as the reception source port data 2702.

  Next, the data receiving apparatus 200 connects to the mail server 300 via the control unit 250. The data receiving device 200 connects to the port of the transmission source port data 2703 determined by the port determination unit 230 and receives mail data.

Then, the data reception device 200 transfers the received mail data to the analysis unit 260. The analysis unit 260 analyzes the received mail data in the same manner as described above.
((Processing on second divided data-from data receiving device to data transmitting device))
The data receiving apparatus 200 creates mail data shown in FIG. 4 by the mail creating unit 240 in order to notify the data transmitting apparatus 100 that the data has been received.

  Next, the port determining unit 230 of the data receiving apparatus 200 determines a port number for transmitting mail to the mail server 300. With reference to FIG. 8, a process for determining the port number will be described. First, the port determination unit 230 checks whether or not the transmission source phrase 2704 and the reception source phrase 2705 are stored in the storage unit 270 (step S7001). Since it is stored, the port determination unit 230 checks whether or not a new mail is received (step S7002). Since the mail is not received when the mail is transmitted (“No” in Step S7002), the port determination unit 230 does not change the transmission source port data 2703 and the reception source port data 2702 stored in the storage unit 270 (Step S7002). S7008).

  Next, the data receiving apparatus 200 connects to the mail server 300 via the control unit 250. The data receiving apparatus 200 connects to the port of the transmission source port data 2703 determined by the port determination unit 230 and transmits mail data.

  The mail server 300 receives mail from the data receiving device 200. The SMTP processing unit 310 receives mail at the port number indicated by the transmission source port data 2703. The received mail data is transferred to the POP processing unit 320 and waits for reception from the data transmission device 100. The POP processing unit 320 waits at a standby port having a number obtained by adding “85” to the SMTP standby port number.

  Next, the port determination unit 130 of the data transmission device 100 determines a port number for connecting to the mail server 300. Processing for determining a port number will be described with reference to FIG. First, the port determination unit 130 checks whether or not the transmission source phrase 1704 and the reception source phrase 1705 are stored in the storage unit 170 (step S6001). Since the transmission source phrase 1704 and the reception source phrase 1705 are stored in the storage unit 170 (“Yes” in step S6001), the port determination unit 130 checks whether or not to newly transmit an email (step S6002). ). Since the mail is not transmitted when it is received (“No” in step S6002), the port determination unit 130 does not change the transmission source port data 1702 and the reception source port data 1703 stored in the storage unit 170 (step S6008). ).

  Next, the data transmitting apparatus 100 connects to the mail server 300 via the control unit 150. The data transmission apparatus 100 connects to the port of the reception source port data 1703 determined by the port determination unit 130 and receives mail data.

  Next, the data transmission device 100 transfers the received mail data to the analysis unit 160. The analysis unit 160 analyzes the received mail data in the same manner as described above.

This is the description of the processing related to the second divided data.
((Processing regarding subsequent divided data))
In the case where the data is divided into three or more by the data dividing unit 120 of the data transmitting apparatus 100, the mail transmission / reception system also performs the above-described processing related to the second divided data for the third and subsequent divided data.

  If the data transmitting apparatus 100 has not received a result notification corresponding to the transmitted mail data, the data transmitting apparatus 100 transmits the same mail data again. As a result, the data receiving device 200 can receive the divided first data in order.

  The data reception device 200 recognizes that the last divided data has been received, based on information included in the “Content-Type: message / partial” header. The information is the same as the above-mentioned information indicating how many pieces of mail data are divided, the information indicating what number the divided data is, and the divided data created by dividing the same mail data. Identifier. Based on these pieces of information, the data combining unit 220 combines a plurality of divided data 2701 stored in the storage unit 270. The data combining unit 220 removes the “Content-Type: message / partial” header added to each divided data 2701. Then, the data combining unit 220 recovers the transmission target data before the division by sequentially combining the divided data transmitted from the data transmitting apparatus 100 first.

  Thereby, the transmission of the mail data from the data transmission device 100 to the data reception device 200 is completed.

  The present embodiment has been described on the assumption that the transmission target data is transmitted from the data transmission device 100 to the data reception device 200. However, regardless of this form, the two devices may both have the functions of both the data transmission device 100 and the data reception device 200, and allow both devices to transmit the transmission target data. .

  As described above, the second embodiment has an effect that it is possible to send and receive e-mails with higher reliability without requiring an additional device.

  This is because the mail transmission / reception system according to the present embodiment determines a port number to be used when the data transmission apparatus 100 transmits mail data, and uses a different port number each time. This is performed by the data transmission device 100 and the data reception device 200 determining the port number to be used based on the transmission source phrase and the reception source phrase.

  Further, even when the data receiving device is not a data receiving device according to the present embodiment but a general mail receiving device, it can receive as divided data. This is because the data transmission device uses the 25th port as the transmission source port and the 110th port as the reception source port when the reception source phrase cannot be acquired.

(Hardware configuration)
In the embodiment described above, each unit illustrated in FIGS. 1 and 2 may be practiced by a dedicated device, but can be regarded as a function (processing) unit (software module) of a software program. However, various configurations can be envisaged when mounting each part shown in these drawings. An example of the hardware environment in such a case will be described with reference to FIG.

  FIG. 9 is a diagram illustrating an exemplary hardware configuration of a computer (information processing apparatus) that can implement the first and second embodiments of the present invention. That is, FIG. 9 shows a configuration of a computer (information processing apparatus) capable of realizing all or part of the information processing apparatus 10 shown in FIG. 1, the data transmission apparatus 100 and the data reception apparatus 200 shown in FIG. FIG. 9 shows a hardware environment capable of realizing each function in the above-described embodiment.

The information processing apparatus 9000 illustrated in FIG. 9 includes the following apparatuses, and has a configuration in which these are connected via a bus 9007.
CPU (Central Processing Unit) 9001
-Display 9002,
・ Communication interface (I / F) 9003,
・ ROM (Read Only Memory) 9004,
A RAM (Random Access Memory) 9005 and a hard disk device (HD) 9006.

  The hard disk device (HD) 9006 stores a program group 9006A and various kinds of stored information 9006B. The program group 9006A is, for example, a computer for realizing a function corresponding to each block (each unit) of the information processing apparatus 10 illustrated in FIG. 1 and the data transmission apparatus 100 and the data reception apparatus 200 illustrated in FIG. It is a program. The various storage information 9006B is, for example, the storage unit 170 and the storage unit 270 illustrated in FIG. A communication interface 9003 is a general communication unit that realizes communication with an external device via the network 9100.

  In the information processing apparatus 9000, the CPU 9001 of the hardware executes a computer program capable of realizing the functions of the block diagram or the flowchart referred to in the description of the above-described embodiment. That is, the CPU 9001 executes the computer program using the hardware resources of the information processing apparatus 9000 shown in FIG. 9 to achieve the functions of the embodiment of the present invention. Specifically, when the data transmission device 100 and the data reception device 200 are realized by the information processing device 9000, the information processing device 9000 may perform the following processing. That is, in the information processing apparatus 9000, the CPU 9001 only needs to execute a computer program for executing the processing steps of the flowcharts shown in FIGS. The computer program supplied to the information processing apparatus 9000 may be stored in a readable / writable RAM 9005 or a non-volatile storage device (storage medium) such as the hard disk device 9006.

  In the above-described case, a general procedure can be adopted as a method for supplying a computer program into the apparatus. The supply method includes, for example, a method of installing in the apparatus via various storage media such as a CD-ROM, and a method of downloading from the outside via a network 9100 such as the Internet. In such a case, the embodiment of the present invention can be regarded as being configured by a code constituting the computer program or a computer-readable storage medium in which the code is recorded.

  While the present invention has been described with reference to the embodiments, the present invention is not limited to the above embodiments. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention.

(Appendix 1)
Port determination means for determining a port number to be used when sending and receiving to a mail server;
An information processing apparatus comprising: control means for accessing the mail server using the port number determined by the port determining means.

(Appendix 2)
The information processing apparatus according to appendix 1 is the first information processing apparatus, and the information processing apparatus according to appendix 1 different from the first information processing apparatus is the second information processing apparatus.
The mail transmitted from the first information processing apparatus is passed through the mail server,
A mail transmission / reception system that is received by the second information processing apparatus according to attachment 1.

(Appendix 3)
The first information processing apparatus divides transmission target data into a plurality of divided data, and transmits an email including the divided data.
The second information processing apparatus that has received the e-mail transmits a result notification notifying that the e-mail has been received,
The mail transmission / reception system according to appendix 2, wherein the first information processing apparatus that has received the result notification transmits the next divided data.

(Appendix 4)
The first information processing apparatus stores a transmission source phrase composed of a unique character string in the own apparatus, adds the transmission source phrase to the mail, and transmits the mail.
The mail transmission / reception system according to supplementary note 3, wherein the second information processing apparatus stores a reception source phrase including a unique character string in its own device, and transmits the result notification with the reception source phrase added thereto.

(Appendix 5)
The first information processing apparatus stores the transmission source phrase in its own apparatus, and the reception source phrase is included in the result notification transmitted from the second information processing apparatus. When sending mail, the port determination means determines the port number based on the transmission source phrase and the reception source phrase, stores the determined port number in the own device, and uses the port number The mail transmission / reception system according to appendix 4, wherein the control means accesses the mail server.

(Appendix 6)
The second information processing apparatus stores the reception source phrase in its own apparatus, and mail when the transmission source phrase is included in the mail transmitted from the first information processing apparatus. The port determination unit determines the port number based on the transmission source phrase and the reception source phrase, stores the determined port number in the own device, and uses the port number. The mail transmission / reception system according to appendix 4, wherein the control means accesses the mail server.

(Appendix 7)
The first information processing apparatus does not store the transmission source phrase in its own apparatus, or when the reception source phrase is not included in the result notification transmitted from the second information processing apparatus. The port determination means determines the port number to a predetermined value, stores the determined port number in the own device, and uses the port number to access the mail server by the control means. The mail transmission / reception system according to appendix 4.

(Appendix 8)
When the second information processing device does not store the reception source phrase in its own device, or when the transmission source phrase is not included in the mail transmitted from the first information processing device, The port determining means determines the port number to a predetermined value, stores the determined port number in the own apparatus, and uses the port number to access the mail server by the control means. The mail transmission / reception system according to appendix 4.

(Appendix 9)
The first information processing apparatus stores the transmission source phrase in its own apparatus, and the reception source phrase is included in the result notification transmitted from the second information processing apparatus. When receiving a mail, the port determining means determines the port number to be used by the port number stored in the device, and uses the port number to access the mail server by the control means. The mail transmission / reception system according to appendix 4.

(Appendix 10)
The second information processing apparatus stores the reception source phrase in its own apparatus, and mail when the transmission source phrase is included in the mail transmitted from the first information processing apparatus. When the port determining means determines the port number to be used as the port number stored in the device, and uses the port number to access the mail server using the port number. 4. The mail transmission / reception system according to 4.

(Appendix 11)
11. The mail transmitting / receiving system according to any one of appendices 2 to 10, wherein the mail server includes a plurality of SMTP standby port numbers and a plurality of POP standby port numbers.

(Appendix 12)
The mail transmitting / receiving system according to claim 11, wherein the mail server transfers mail data when a connection is made to the standby port number of the waiting POP among the standby port numbers of the plurality of POPs.

(Appendix 13)
A mail transmission / reception method for determining a port number to be used for transmission and reception to a mail server and accessing the mail server using the port number.

(Appendix 14)
Port determination processing for determining the port number used when sending and receiving to the mail server;
A computer program for causing a computer to implement control processing for accessing the mail server using the port number determined by the port determination processing.

DESCRIPTION OF SYMBOLS 10 Information processing apparatus 13 Port determination part 15 Control part 100 Data transmission apparatus 110 Data preparation part 120 Data division part 130 Port determination part 140 Mail preparation part 150 Control part 160 Analysis part 170 Storage part 200 Data reception apparatus 220 Data connection part 230 Port Determination unit 240 Mail creation unit 250 Control unit 260 Analysis unit 270 Storage unit 300 Mail server 310 SMTP processing unit 320 POP processing unit 400 LAN
1701 Division data 1702 Transmission source port data 1703 Reception source port data 1704 Transmission source phrase 1705 Reception source phrase 1706 Transmission source message ID
2701 Division data 2702 Reception source port data 2703 Transmission source port data 2704 Transmission source phrase 2705 Reception source phrase 2706 Transmission source message ID
2707 Source mail address 9000 Information processing device 9001 CPU
9002 Display 9003 Communication interface 9004 ROM
9005 RAM
9006 Hard disk device 9006A Program group 9006B Various storage information 9007 Bus 9100 Network

Claims (10)

Port determination means for determining a port number to be used when sending and receiving to a mail server;
An information processing apparatus comprising: control means for accessing the mail server using the port number determined by the port determining means. The information processing device according to claim 1 is a first information processing device, and the information processing device according to claim 1 different from the first information processing device is a second information processing device.
The mail transmitted from the first information processing apparatus is passed through the mail server,
A mail transmission / reception system received by the second information processing apparatus. The first information processing apparatus divides transmission target data into a plurality of divided data, and transmits an email including the divided data.
The second information processing apparatus that has received the e-mail transmits a result notification notifying that the e-mail has been received,
The mail transmission / reception system according to claim 2, wherein the first information processing apparatus that has received the result notification transmits the next divided data. The first information processing apparatus stores a transmission source phrase composed of a unique character string in the own apparatus, adds the transmission source phrase to the mail, and transmits the mail.
4. The mail transmission / reception system according to claim 3, wherein the second information processing apparatus stores a reception source phrase composed of a unique character string in its own apparatus and transmits the result notification with the reception source phrase added thereto. 5. The first information processing apparatus stores the transmission source phrase in its own apparatus, and the reception source phrase is included in the result notification transmitted from the second information processing apparatus. When sending mail, the port determination means determines the port number based on the transmission source phrase and the reception source phrase, stores the determined port number in the own device, and uses the port number The mail transmission / reception system according to claim 4, wherein the mail server is accessed by the control means. The second information processing apparatus stores the reception source phrase in its own apparatus, and mail when the transmission source phrase is included in the mail transmitted from the first information processing apparatus. The port determination unit determines the port number based on the transmission source phrase and the reception source phrase, stores the determined port number in the own device, and uses the port number. The mail transmission / reception system according to claim 4, wherein the control means accesses the mail server. The first information processing apparatus does not store the transmission source phrase in its own apparatus, or when the reception source phrase is not included in the result notification transmitted from the second information processing apparatus. The port determination means determines the port number to a predetermined value, stores the determined port number in the own device, and uses the port number to access the mail server by the control means. The mail transmission / reception system according to claim 4. The first information processing apparatus stores the transmission source phrase in its own apparatus, and the reception source phrase is included in the result notification transmitted from the second information processing apparatus. When receiving a mail, the port determining means determines the port number to be used by the port number stored in the device, and uses the port number to access the mail server by the control means. The mail transmission / reception system according to claim 4.   A mail transmission / reception method for determining a port number to be used for transmission and reception to a mail server and accessing the mail server using the port number. Port determination processing for determining the port number used when sending and receiving to the mail server;
A computer program for causing a computer to implement control processing for accessing the mail server using the port number determined by the port determination processing.

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