JP5177907B2 - E-mail transmitting / receiving apparatus, e-mail receiving method, e-mail receiving program, and program recording medium - Google Patents

Description

  The present invention relates to an e-mail transmission / reception device, an e-mail receiving method, an e-mail receiving program, and a program recording medium, and in particular, when a mail including a large amount of data is divided into a plurality of partial mail elements and transmitted / received. The present invention relates to an e-mail transmission / reception apparatus, an e-mail receiving method, an e-mail receiving program, and a program recording medium that can appropriately receive a divided mail composed of a plurality of partial mail elements stored in a server. The present invention can be suitably applied to, for example, a portable terminal having an electronic mail transmission / reception function.

  Usually, when an e-mail transmission / reception apparatus mounted on an information processing apparatus receives a mail for the e-mail transmission / reception apparatus from a mail server (POP3 server: Post Office Protocol Version 3 Server), for example, Patent Document 1 As described in Japanese Patent Application Laid-Open No. 2003-101588 “Receiving Mail Server” and Japanese Patent Application Laid-Open No. 2005-182543 “Electronic Mail System”, the information is temporarily stored in a mail box in the mail server. The received mail is sequentially received regardless of the contents of each mail, and after completion of the reception of each mail, the operation of sequentially deleting the mail from the mail box in the mail server is repeated. This will be described with reference to the sequence chart of FIG. FIG. 14 is a sequence chart for explaining a current operation sequence at the time of mail reception between the electronic mail transmitting / receiving apparatus and the mail server.

  In the sequence chart of FIG. 14, when an e-mail receiving operation is instructed by the user, the e-mail transmitting / receiving apparatus connects to the mail server (POP3) (sequence Seq141), and then includes POP3 including the user name and password. An authentication request is transmitted (sequence Seq142). When the mail server that has received the POP3 authentication request obtains user authentication regarding the requesting electronic mail transmitting / receiving apparatus, an OK response is returned (sequence Seq 143).

  When the OK response is received, the e-mail transmission / reception apparatus transmits a mail number confirmation request for inquiring the number of mails for the e-mail transmission / reception apparatus stored in the mailbox to the mail server (sequence Seq144). In the mail server that received the mail number confirmation request, check the number of mails for the requesting e-mail sending / receiving device stored in the mailbox, and send the confirmed number of e-mails, for example, 5 to the requesting e-mail It returns to the device (sequence Seq145).

  An e-mail transmission / reception device that has received notification that the number of e-mails stored in the mail server mailbox is, for example, 5 is not limited to the contents of all stored e-mails. First, a first mail data download request, that is, a RETR1 command (reception (mail # 1)) is transmitted to the mail server (sequence Seq 146), and the first mail data is downloaded from the mail server mailbox. The second mail data is downloaded (sequence Seq147).

  When the download of the first mail data is completed and the reception process is completed, the electronic mail transmitting / receiving apparatus transmits a deletion request for the first mail data, that is, a DELE1 command (deletion (mail # 1)) to the mail server. (Sequence Seq148). The mail server that received the first mail data deletion request, that is, the DELE1 command (delete (mail # 1)) deleted the first mail data from the mailbox and deleted the first mail data. An OK response indicating this is returned to the requesting electronic mail transmitting / receiving apparatus (sequence Seq149).

  The electronic mail transmitting / receiving apparatus repeats the mail data receiving operation (downloading operation) as described above for the number of mails confirmed in the sequence Seq145, for example, five, so that all of the data stored for the electronic mail transmitting / receiving apparatus are stored. The mail data is downloaded to the electronic mail transmission / reception device to perform reception processing, and all the mail data for the electronic mail transmission / reception device 1 stored in the mail server mailbox is deleted.

  That is, when the download operation of the first mail data is completed and the reception process is completed, the electronic mail transmitting / receiving apparatus transmits a second mail data download request, that is, a RETR2 command (reception (mail # 2)). (Sequence Seq150), after the second mail data is downloaded from the mail server mailbox and the reception process is completed (sequence Seq151), the second mail data deletion request, that is, the DELE2 command (deletion (mail # 2)) is transmitted (sequence Seq152), and an OK response indicating that the second mail data is deleted from the mailbox is received from the mail server (sequence Seq153).

  The same download operation is repeated for the third and fourth mail data, and the number of mails confirmed in the sequence Seq145, for example, the last fourth previous mail data for five is received. Upon completion, the e-mail transmitting / receiving apparatus transmits a download request for the last fifth mail data, that is, a RETR5 command (reception (mail # 5)) (sequence Seq154), and the fifth mail data from the mail server mailbox is transmitted. After downloading the mail data and completing the reception process (sequence Seq 155), by sending a fifth mail data deletion request, that is, a DELE5 command (deletion (mail # 5)) (sequence Seq 156), the mailbox OK indicating that the fifth mail data has been deleted from The received from the mail server Pons (sequence Seq157).

  When all the mail data for the number of e-mails confirmed in sequence Seq145, for example, 5 e-mails are downloaded, the e-mail transmission / reception apparatus sends an e-mail reception operation end notification to the e-mail server (sequence Seq158), and the e-mail receiving the end notification When the server completes the mail delivery operation end process and receives an OK response indicating that the end process has been completed from the mail server (sequence Seq159), the connection with the mail server is disconnected (sequence Seq160).

  As described above, the e-mail transmitting / receiving apparatus performs the mail receiving operation regardless of the type of mail temporarily stored in the mail server mailbox or the contents of the mail. An operation of downloading all the mail data temporarily stored in the e-mail transmission / reception apparatus to the e-mail transmission / reception apparatus is performed. For example, the case where a mail temporarily stored in a mailbox is divided into a plurality of partial mail elements is no exception. In addition, as for the divided mail divided into a plurality of partial mail elements as described above, for some reason (for example, one or more of the partial mail elements are lost due to a malicious attack. If the mail server does not arrive for some reason on the communication network side for mail distribution, etc.), even if all of the partial mail elements of the split mail do not exist on the mail server Absent.

Japanese Patent Laying-Open No. 2003-101588 (page 2-3) Japanese Patent Laying-Open No. 2005-182543 (page 5-6)

  As described above, regardless of the type of mail temporarily stored in the mail server mailbox or the content of the mail, all mail data temporarily stored in the mailbox is downloaded to the e-mail transmission / reception device. In the mail receiving operation, the mail temporarily stored in the mail server mailbox is divided into a plurality of partial mail elements and, for example, one of the plurality of mails If one or more partial mail elements are lost due to malicious attacks, or if they do not arrive for some reason on the communication network for mail delivery, etc., in the mail server mailbox If all the partial mail elements divided into multiple mails do not exist, It is impossible to edit the complete email by combining all parts mail elements for the electronic mail sending and receiving device, so that would download (receive) as unwanted mail useless.

  As a result, the e-mail transmission / reception apparatus has a problem in that the memory is unnecessarily occupied by unnecessary mail that is useless and the memory capacity may be compressed. Further, the user of the e-mail transmission / reception apparatus that has received an unnecessary useless mail has to delete the mail one by one with a cumbersome manual operation, which deteriorates operability. On the other hand, depending on the timing of the mail receiving operation from the e-mail transmission / reception device, the partial mail element is a divided mail which is highly likely to have all of the plurality of partial mail elements in the mail server mailbox. However, if you simply give up on receiving the split mail as a split mail that is not useful, it will repeat the operation of sending it again from the sender, and it will waste time to receive the mail. There is also a problem that it will end up.

(Object of the present invention)
The present invention has been made in view of such circumstances, and when a mail (divided mail) divided into a plurality of partial mail elements is stored in the mail server at the time of mail reception, the partial mail element E-mail transmission / reception device and e-mail that prevent the operation to download from the mail server with respect to the divided mail that has been determined to be more reliable whether it is unnecessary and unnecessary unnecessary mail To provide a receiving method, an e-mail receiving program, and a program recording medium.

  In order to solve the above-mentioned problems, the electronic mail transmitting / receiving apparatus according to the present invention employs the following characteristic configuration.

  (1) An e-mail transmission / reception apparatus that transmits / receives e-mails via a mail server, and stores e-mail transmission / reception apparatuses stored in the e-mail server when receiving mail from the mail server As a result, when it is detected that there is a divided mail divided into a plurality of partial mail elements and that all of the partial mail elements of the divided mail are not present in the mail server, the current time is Wait until the first predetermined elapsed time determined in advance from the transmission time of the divided mail, and then, when the first predetermined elapsed time has elapsed, all of the partial mail elements of the divided mail are the mail Check if it exists in the server. If it does not exist, it will be sent as an irregular split mail from the mail server. Without performing the reception operation of the division mail, e-mail transmission and reception apparatus for performing an instruction to delete the division mail from the mail server.

  According to the electronic mail transmitting / receiving apparatus, electronic mail receiving method, electronic mail receiving program, and program recording medium of the present invention, the following effects can be obtained.

  The first effect is that even when a divided mail in which all of the divided partial mail elements are not arranged for some reason is present in the mail server during the mail receiving operation in the electronic mail transmitting / receiving apparatus, When the predetermined elapsed time has passed after waiting for a predetermined elapsed time from the time when the mail was sent or when it was detected that there was a partial mail with irregular partial mail elements If all the partial mail elements of the split mail are complete, the split mail is downloaded and the reception process is performed, so there is no need to re-send the split mail from the sender. The receiving side can also receive the divided mail more quickly. Furthermore, even when the predetermined elapsed time has elapsed, if the partial mail elements of the divided mail are not uniform, the receiving side does not perform the operation of receiving the irregular and invalid divided mail. Can reliably prevent the pressure on the memory resources of the e-mail transmission / reception apparatus of the e-mail, and the divided e-mails with partial e-mail elements are automatically deleted from the e-mail server. This eliminates the need for manual removal from the system.

  The second effect is that when a divided mail whose partial mail elements are irregular is detected, a predetermined elapsed time for waiting for the reception operation of the divided mail is set by the sender of the divided mail to an arbitrary value. Or it is possible to set a pre-specified value according to the email address and domain of the sender of the split email, so that the human between sending and receiving email accompanying the deletion of the split email In addition to avoiding trouble, it is possible to optimize the time during which the divided mail stays in the mail server.

It is a block block diagram which shows an example of the block configuration of the email transmission / reception apparatus which concerns on this invention. It is a functional block diagram which shows an example of a function structure of the email transmission / reception apparatus shown in FIG. It is a sequence chart for demonstrating the operation | movement sequence at the time of the mail reception between the electronic mail transmission / reception apparatus which concerns on this invention, and a mail server as a 1st operation example. It is a flowchart for demonstrating an example of the flow of a process which analyzes the header data of the received mail in the electronic mail transmission / reception apparatus which concerns on this invention. It is a schematic diagram for demonstrating an example of the mail format preserve | saved at the mail server in the electronic mail transmission / reception apparatus which concerns on this invention. It is a sequence chart for demonstrating the operation | movement sequence at the time of the mail reception between the electronic mail transmission / reception apparatus which concerns on this invention, and a mail server as a 2nd operation example. It is a sequence chart for demonstrating the operation | movement sequence at the time of the mail reception between the electronic mail transmission / reception apparatus which concerns on this invention, and a mail server as a 3rd operation example. It is a table which shows an example of the mail format of the mail for division | segmentation mail abnormality notification transmitted to the sender of the division | segmentation mail used as the deletion object in the email transmission / reception apparatus which concerns on this invention. It is a sequence chart for demonstrating the operation | movement sequence at the time of the mail reception between the electronic mail transmission / reception apparatus which concerns on this invention, and a mail server as a 4th operation example. It is a flowchart for demonstrating an example of the flow of a process which determines the possibility of deletion of a division | segmentation mail in the email transmission / reception apparatus which concerns on this invention. It is a block block diagram which shows the other example of the block configuration of the email transmission / reception apparatus which concerns on this invention. It is a table which shows an example of the mail format which inserted the predetermined elapsed time designation | designated information for the decision | availability determination of the deletion of a division | segmentation mail in the header part of the division | segmentation mail in the electronic mail transmission / reception apparatus which concerns on this invention. It is a table which shows the other example of the mail format of the mail for division | segmentation mail abnormality notifications transmitted with respect to the sender of the division | segmentation mail used as the deletion object in the email transmission / reception apparatus which concerns on this invention. It is a sequence chart for demonstrating the present operation | movement sequence at the time of mail reception between an electronic mail transmission / reception apparatus and a mail server.

  Preferred embodiments of an electronic mail transmitting / receiving apparatus, electronic mail receiving method, electronic mail receiving program, and program recording medium according to the present invention will be described below with reference to the accompanying drawings. In the following description, the e-mail transmitting / receiving apparatus and e-mail receiving method according to the present invention will be described. However, the e-mail receiving method may be implemented as an e-mail receiving program executable by a computer. Alternatively, it goes without saying that the e-mail receiving program may be recorded on a computer-readable recording medium.

(Features of the present invention)
Prior to the description of the embodiments of the present invention, an outline of the features of the present invention will be described first. In the present invention, when the electronic mail transmitting / receiving apparatus receives mail from the mail server, the mail for the electronic mail transmitting / receiving apparatus stored in the mail server is a single mail that forms a single mail. If it is detected that the divided mail divided into multiple partial mail elements is stored, whether all the partial mail elements of the divided mail exist in the mail server (combinable) If all of the partial mail elements of the divided mail are not present in the mail server, the divided mail is not downloaded from the mail server and received. A feature is that all the partial mail elements of the divided mail that are irregular are deleted from the mail server.

  However, if a plurality of partial mail elements that are irregular in the divided mail are simply deleted from the mail server, the remaining divided mail elements are being sent to the mail server (for example, The first partial mail element of the split mail is stored in the mail server, but the second partial mail element is currently being received by the mail server, etc.) Therefore, in order to prevent such a situation, it is also characterized by having a function of deferring the execution of the divided mail. Here, there are various variations in the method for determining whether to perform deletion or hold, and all the divided partial mail elements are divided without pressing the memory resources of the mail server as much as possible. It is characterized in that deletion is put on hold only with respect to proper divided mails that are likely to be collected.

  In addition, it is characterized by notifying the sender of the divided mail and the recipient of the divided mail as a divided mail abnormality notification that the divided mail having a plurality of partial mail elements has been deleted from the mail server. Yes. At this time, it is characterized in that an appropriate amount (a part or all) of mail data (mail body) of the deleted divided mail is included in the notification contents of the divided mail abnormality notification as much as possible.

  Furthermore, when determining whether or not to delete a divided mail in which a plurality of partial mail elements are not aligned, the electronic mail transmitting / receiving apparatus checks the transmission time of the divided mail with the current time, and the current time is If the predetermined elapse time exceeds a predetermined first elapse time from the transmission time of the e-mail, the divided mail is deleted from the mail server, but the elapse time has not elapsed until the first elapse time. Suspends the deletion of the divided mail from the mail server, temporarily terminates the mail reception operation with the mail server, and then, when the first predetermined elapsed time has elapsed, again returns to the mail server. It is characterized by accessing and reconfirming whether or not all the partial mail elements constituting the divided mail are prepared.

  Furthermore, when the e-mail transmitting / receiving apparatus determines whether or not to delete a divided mail in which a plurality of partial mail elements are irregular, when detecting a divided mail in which a plurality of partial mail elements are irregular, While the deletion of the divided mail from the mail server is put on hold, the timer is started and the mail reception operation with the mail server is once ended. Then, the time measured by the timer is set as a second time predetermined. As a comparison result with the predetermined elapsed time, when the time measured by the timer reaches the second predetermined elapsed time, the mail server is accessed again, and all the partial mail elements constituting the divided mail are It is characterized by reconfirming whether or not it is complete.

  Further, the first predetermined elapsed time for collating with the current time and the second predetermined elapsed time for collating with the time measured by the timer are respectively the mail address of the sender of the split mail or the domain of the sender. According to this, it is characterized by setting to a value designated in advance.

  Further, the first predetermined elapsed time for collating with the current time and the second predetermined elapsed time for collating with the time measured by the timer are determined in advance by the e-mail transmitting / receiving device on the split mail receiving side. This is characterized in that it is possible to set not only the value set to the specified value but also the value specified by using the header part of the divided mail on the divided mail transmission side.

  That is, the present invention more specifically has the following mechanism. When the electronic mail transmitting / receiving apparatus receives mail from the mail server, it performs an operation of receiving only the header of the mail to be received before receiving the mail body (mail data) for each case. In the header, as described in RFC (Request For Comment) 2046 recommendation, “identification information whether or not the message is a divided mail”, “divided mail ID (uniquely assigned to each partial mail element fragmented as a divided mail) ID added for identification) ”,“ total number of fragments (total number of fragments) ”,“ division number (indicating the number of partial mail elements corresponding to the partial mail element from which the corresponding partial mail element is fragmented) Number) ”is included.

  When the e-mail transmission / reception device receives only the mail header, it determines whether the mail to be received is a split mail based on the information contained in the header, and if it is not a split mail The mail body (mail data) is received as a normal mail.

  On the other hand, if it is a split mail, the remaining mail in the mail server is targeted and the header-only receiving operation is continued, and the same split as the partial mail element of the split mail first found as the mail to be received A mail having a mail ID is searched as a partial mail element of the divided mail first found, and all mails having the same divided mail ID are extracted as partial mail elements of the divided mail first found. Thereafter, it is confirmed whether or not the total number of partial mail elements of the extracted divided mail is the same as the total number of divisions stored in the header of the first divided mail found.

  If the total number of extracted partial email elements is the same as the total number of divisions stored in the header of the first found segmented email, all of the emails to be received (the first found segmented email) The operation of receiving all mails having the same divided mail ID as that mail, including the mail to be received (the partial mail element of the first divided mail found), by determining that the partial mail elements are prepared. Do.

  On the other hand, if the total number of extracted partial mail elements is less than the total number of divisions stored in the header of the first found divided mail, the partial mail related to the mail to be received (first found divided mail) All elements that have the same split mail ID as the mail, including the mail to be received (partial mail element of the first found split mail), judging that it is a useless mail that does not contain all of the elements The mail is assumed to be deleted from the mail server on the assumption that it is only a part of the partial mail elements constituting the divided mail.

  However, all mails that have the same split mail ID as the mail, including the mail to be received (partial mail element of the first split mail found), are simply assumed to be uneven partial mail elements. If the deletion from the mail server is performed, the remaining partial mail elements are being sent to the mail server (for example, the first partial mail element of the divided mail is the mail server) But the second partial mail element is deleted from the mail server even if it should not be deleted, if the second partial mail element is being received by the mail server) Become. Therefore, it is determined whether or not deletion of mail from the mail server is possible. If deletion is possible, deletion is performed. If deletion is not possible, deletion is carried forward until the next mail reception operation. I will decide.

  In addition, it is possible to give variations to the determination of whether or not to delete a divided mail with uneven partial mail elements from the mail server. By applying such a variation, it is possible to reduce the memory capacity of the mail server as much as possible. It is possible to suppress. For example, when the electronic mail transmitting / receiving apparatus determines whether or not to delete a divided mail in which a plurality of partial mail elements are not uniform, the transmission time of the divided mail is set to an RTC (Real Time Clock) in the electronic mail transmitting / receiving apparatus. ) Is compared with the current time being timed, and if the current time has passed a first predetermined elapsed time that is determined in advance from the transmission time of the divided mail, the mail server of the divided mail Execute deletion of.

  On the other hand, if the current time has not elapsed until the first predetermined elapsed time, the deletion of the divided mail from the mail server is put on hold, and the mail reception operation with the mail server is temporarily terminated. Later, when the first predetermined elapsed time has passed, the mail server is accessed again, and it is confirmed whether or not all the partial mail elements constituting the divided mail are prepared. When a plurality of partial mail elements constituting the divided mail are not aligned, the divided mail is deleted from the mail server for the first time.

  Alternatively, when the e-mail transmitting / receiving apparatus determines whether or not to delete the divided mail whose plural partial mail elements are irregular, when the divided mail whose plural partial mail elements are irregular is detected, While the timer is started while the deletion of the divided mail from the mail server is put on hold, the mail reception operation with the mail server is once terminated, and the time measured by the timer and a predetermined second predetermined elapsed time When the time counted by the timer reaches the second predetermined elapsed time as the collation result, the mail server is accessed again, and whether all the partial mail elements constituting the divided mail are available If the partial mail elements that make up the split mail are not complete at that time, the split mail is not displayed for the first time. To execute the deletion from the mail server.

  Here, as described above, the first predetermined elapsed time for collating with the current time and the second predetermined elapsed time for collating with the time measured by the timer are different from each other as described above. It is possible to set a value specified in advance according to each mail address of the source of the divided mail or according to each domain of the source.

  Furthermore, as described above, the first predetermined elapsed time for collating with the current time and the second predetermined elapsed time for collating with the time measured by the timer are the e-mail transmission / reception on the receiving side of the divided mail as described above. In addition to the case where a value determined in advance by the apparatus is used, it is also possible to set the value specified by using the extension header in the header part of the divided mail on the divided mail transmission side.

  In addition, a message indicating that the partial mail element has been deleted from the mail server is displayed on the display unit of the email transmission / reception apparatus that is about to receive the divided mail as a divided mail abnormality notification, or The e-mail is transmitted to the sender side e-mail transmitting / receiving apparatus that has transmitted the divided mail. In addition, when the divided mail abnormality notification is performed, not only a warning message notifying that the partial mail elements constituting the divided mail are insufficient, but also the header information of the mail for identifying the divided mail to be deleted In addition, in some cases, the mail body included in the partial mail element with the division number “1” of the mail (that is, the first partial mail element of each partial mail element of the fragmented divided mail) is possible. As long as it is added, it is notified.

(Configuration example of embodiment)
Next, an example of the configuration of the electronic mail transmitting / receiving apparatus according to the present invention will be described. FIG. 1 is a block diagram showing an example of a block configuration of an electronic mail transmission / reception apparatus according to the present invention, and shows an example of a hardware configuration of the electronic mail transmission / reception apparatus. 1 includes a main control unit 11 that controls the entire apparatus, an operation unit 12 that is operated by a user, a display unit 13 that displays information on a screen, and an RTC (Real Time) that measures the current time. Clock) 14, a LAN controller 15 for controlling a LAN (Local Area Network) line, a ROM (Read Only Memory) 16 for storing fixed information such as a control program and system data, and various data are temporarily saved. A RAM (Random Access Memory) 17 and a FLASH memory 18 which is a nonvolatile memory are included at least.

  Further, the electronic mail transmitting / receiving apparatus 1 shown in FIG. 1 is described from a functional aspect as shown in FIG. FIG. 2 is a functional block diagram illustrating an example of a functional configuration of the electronic mail transmitting / receiving apparatus 1 illustrated in FIG. 1, and each functional element is realized by a control program stored in the ROM 16. As shown in FIG. 2, an e-mail transmitting / receiving apparatus 1 showing an example of an e-mail transmitting / receiving apparatus according to the present invention includes a LAN controller driver 21, a TCP / IP protocol stack 22, a POP3 client 23, an SMTP client 24, The mail reception application 25 and the mail transmission application 26 are configured to include at least each functional element. The mail reception application 25 includes at least a divided mail determination unit 251 and a divided mail deletion availability determination unit 252. Yes.

  The LAN controller driver 21 is a functional element having a function of driving the LAN controller 15 of FIG. 1, and the TCP / IP protocol stack 22 conforms to the TCP / IP (Transmission Control Protocol / Internet Protocol) protocol. It is a functional element that controls the exchange of electronic mail transmitted and received via a LAN line. The POP3 client 23 is a functional element having a client function of a mail reception protocol POP3 (Post Office Protocol Version 3), and the SMTP client 24 has a client function of a mail transmission protocol SMTP (Simple Mail Transfer Protocol). Functional elements.

  The mail receiving application 25 is a functional element that governs the overall operation of mail reception, and the mail transmission application 26 is a functional element that governs the overall operation of mail transmission. Further, the divided mail determination unit 251 included in the mail receiving application 25 has a function of determining whether the received mail is a divided mail or searching for a divided mail having the same divided mail ID. A functional element that has a function of determining whether or not to delete a divided mail when the mail divided into a plurality of mails does not exist in the mail server. It is.

(Description of operation of embodiment)
(First operation example)
Next, an example of the operation of the electronic mail transmitting / receiving apparatus 1 shown in FIGS. 1 and 2 will be described with reference to the sequence chart of FIG. 3, the flowchart of FIG. 4, and the schematic diagram of FIG. FIG. 3 is a sequence chart for explaining, as a first operation example, an operation sequence at the time of mail reception between the electronic mail transmitting / receiving apparatus 1 and the mail server, and is stored in the mail server (POP3). The mail for the electronic mail transmitting / receiving apparatus 1 is not a divided mail divided into a plurality of partial mail elements for all mails (in this embodiment, five mails), but forms a single mail with one mail. An example of the operation when the mail is a normal mail is shown. FIG. 4 is a flowchart for explaining an example of the flow of processing for analyzing the header data of the mail received by the electronic mail transmitting / receiving apparatus, and shows an operation example of the divided mail determination unit 251.

FIG. 5 is a schematic diagram for explaining an example of a mail format stored in the mail server, and FIG. 5A is a configuration example of a normal mail forming a single mail by one mail. FIG. 5B shows a configuration example of the divided mail divided into a plurality of partial mail elements. As shown in FIG. 5, information for identifying the mail configuration is stored in the mail header. For example, in the case of a normal mail as shown in FIG. 51 is “Content-type: multipart / mixed;…”
Is displayed, and there is no indication of “message / partial” indicating a split mail.

On the other hand, in the case of a divided mail as shown in FIG. 5B, each partial mail element constituting the divided mail (in the example of FIG. 5B, divided into three, partial mail elements 1, 2, and 3). Each of the headers 52, 53, and 54 in the example) is “Content-type: message / partial;
Is displayed, indicating that it is a divided mail.

Further, as shown in FIG. 5B, in the headers 52, 53, 54 of the partial mail elements 1, 2, 3 constituting the divided mail, each corresponding partial mail element is fragmented following the content type. The split number indicating the number of the partial mail element corresponding to the first partial mail element and the total number of fragments indicating the total number of fragmented partial mail elements,
“Number = 1; total = 3;”
“Number = 2; total = 3;”
“Number = 3; total = 3;”
, The total number of partial mail elements (total number of divisions) is 3, and the partial mail elements 1, 2, and 3 are respectively the first, second, and third partial mails of the divided mail. Indicates that the element is hit.

Further, as shown in FIG. 5 (B), in order to specify the divided mail following the division number (number) and the total number of divisions (total), each fragmented partial mail element 1, 2, 3 is uniquely identified. The divided mail ID to be added is in any of the partial mail elements 1, 2, and 3.
"Id =" 123456789ABC ";"
The partial mail elements 1, 2, and 3 are partial mail elements constituting the same divided mail.

  In the sequence chart of FIG. 3, as shown in the state of the mailbox in the sequence chart of FIG. 3, the mail for the electronic mail transmitting / receiving apparatus 1 stored in the mail server (POP3) is all mail ( In this embodiment, for 5 mails), each header has “content type” information as shown in FIG. 5A and is a normal mail that forms a single mail in a single mail. Is shown. In such a case, in the sequence chart of FIG. 3, first, when the e-mail transmitting / receiving apparatus 1 is instructed to receive a mail by a user or at a predetermined time, the e-mail receiving application 25 is activated to After connecting to the server (POP3) (sequence Seq1), a POP3 authentication request including the user name and password is transmitted (sequence Seq2). When the mail server that has received the POP3 authentication request obtains user authentication related to the requesting electronic mail transmitting / receiving apparatus, an OK response is returned (sequence Seq3).

  When the OK response is received, the mail receiving application 25 of the e-mail transmitting / receiving apparatus 1 transmits a mail number confirmation request for inquiring the mail number for the e-mail transmitting / receiving apparatus 1 stored in the mail box to the mail server. (Sequence Seq4). In the mail server that has received the mail number confirmation request, the number of mails for the requesting e-mail transmitting / receiving apparatus 1 stored in the mailbox is confirmed, and the number of confirmed e-mails, for example, 5 is determined as the requesting e-mail. It returns to the transmission / reception apparatus 1 (sequence Seq5).

  The mail receiving application 25 of the electronic mail transmitting / receiving apparatus 1 that has received a notification that the number of mails stored in the mail box of the mail server is, for example, 5 is first prepared in the RAM 17 as preparation for receiving mail. Each flag is cleared and initialized (sequence Seq6). Here, each flag prepared in the RAM 17 refers to various flags referred to by the divided mail determination unit 251 in the mail reception application 25 for use in the divided mail determination process and search process. The number of divided fragments for counting the number of divided partial mail elements, the divided mail search status flag indicating the state during the divided mail search for searching each partial mail element constituting the divided mail, and the divided mail are configured. It is a divisional abnormal state flag indicating that the partial mail element is in an abnormal state that is insufficient. Clearing each flag represents clearing the number of divided fragments to “0”, setting the divided mail search flag to “OFF”, and setting the divided abnormal state flag to “OFF”.

  Thereafter, the mail receiving application 25 of the e-mail transmission / reception device 1 only includes the header data portion in ascending order of the e-mail number out of the number of e-mails for the e-mail transmission / reception device 1 stored in the mailbox. In order to perform reception, a download request for the header data of the first mail # 1, that is, a TOP1 command (header reception (mail # 1)) is sent to the mail server (sequence Seq7), from the mail server mailbox. The header data of the first mail # 1 is downloaded (sequence Seq8).

  When the download of the header data of the first mail # 1 is completed, the mail receiving application 25 of the electronic mail transmitting / receiving apparatus 1 analyzes the acquired header data of the first mail # 1 in the divided mail determination unit 251. (Sequence Seq9). An example of the header data analysis processing of the first mail # 1 in the divided mail determination unit 251 is as shown in the flowchart of FIG. That is, in the flowchart of FIG. 4, it is confirmed whether or not there is a display of “message / partial” indicating a divided mail in the “content type” of the acquired header data of the first mail # 1 (step S1).

  In the case of this operation example, the first mail # 1 is a normal mail, and there is no display of “message / partial” as shown in FIG. 5B, so it is not a divided mail in step S1. As a result (No in step S1), it is next determined whether or not each partial mail element constituting the divided mail is being searched with reference to the divided mail searching state flag (step S12). The split mail search status flag is cleared and set to “OFF” at the stage of sequence Seq6 in FIG. 3 (No in step S12), so the header data is not subjected to subsequent analysis processing. The analysis process is terminated, and the first mail # 1 that is not a divided mail is processed as a normal mail.

  Accordingly, the mail receiving application 25 of the electronic mail transmitting / receiving apparatus 1 transmits a download request for the first mail data, which is a normal mail, that is, a RETR1 command (reception (mail # 1)) to the mail server (sequence Seq10). The first mail data is downloaded from the mail box of the mail server, and the reception process is performed (sequence Seq11).

  When the download of the first mail data is completed and the reception process is completed, the mail reception application 25 of the electronic mail transmitting / receiving apparatus 1 requests the deletion of the first mail data, that is, the DELE1 command (deletion (mail # 1)). ) Is transmitted to the mail server (sequence Seq12). The mail server that received the first mail data deletion request, that is, the DELE1 command (delete (mail # 1)) deleted the first mail data from the mailbox and deleted the first mail data. An OK response indicating this is returned to the requesting electronic mail transmitting / receiving apparatus 1 (sequence Seq13).

  The mail receiving application 25 of the electronic mail transmitting / receiving apparatus 1 stores the mail data for the electronic mail transmitting / receiving apparatus 1 by repeating the download operation of the mail data for the number of mails confirmed in the sequence Seq5, for example, five. Download all the mail data to the e-mail transmission / reception device 1 and perform the reception process, and delete all the e-mail data for the e-mail transmission / reception device 1 stored in the mail server mailbox. .

  That is, when the download operation of the first mail data is completed and the reception process is completed, the mail reception application 25 of the electronic mail transmitting / receiving apparatus 1 downloads the header data of the second mail # 2, that is, TOP2. By sending a command (header reception (mail # 2)) to the mail server (sequence Seq14), the header data of the second mail # 2 is downloaded from the mail server mailbox (sequence Seq15) and downloaded. The header data of the second mail # 2 is analyzed (sequence Seq16).

  As a result of analyzing the header data of the second mail # 2, if it is determined that the mail is not a divided mail but a normal mail, a second mail data download request, that is, a RETR2 command (reception (mail # 2)) Is transmitted (sequence Seq17), the second mail data is downloaded from the mailbox of the mail server, and the reception process is completed (sequence Seq18), then the second mail data deletion request, that is, the DELE2 command By transmitting (delete (mail # 2)) (sequence Seq19), an OK response indicating that the second mail data has been deleted from the mailbox is received from the mail server (sequence Seq20).

  The same downloading operation is repeated for the third and fourth mail data, and the number of mails confirmed in the sequence Seq5, for example, the last fourth previous mail data for five is downloaded. When the reception processing is completed, the mail reception application 25 of the electronic mail transmitting / receiving apparatus 1 mails a download request for header data of the fifth mail # 5, that is, a TOP5 command (header reception (mail # 5)). By transmitting to the server (sequence Seq21), the header data of the fifth mail # 5 is downloaded from the mailbox of the mail server (sequence Seq22), and the header data of the downloaded fifth mail # 5 is analyzed. (Sequence Seq23).

  As a result of analyzing the header data of the fifth mail # 5, when it is determined that the mail is not a divided mail but a normal mail, a fifth mail data download request, that is, a RETR5 command (reception (mail # 5)) Is transmitted (sequence Seq24), the fifth mail data is downloaded from the mailbox of the mail server, and the reception process is completed (sequence Seq25), then the fifth mail data deletion request, that is, the DELE5 command By transmitting (delete (mail # 5)) (sequence Seq26), an OK response indicating that the fifth mail data has been deleted from the mailbox is received from the mail server (sequence Seq27).

  When all the mail data for the number of mails confirmed in the sequence Seq5, for example, 5 mails are downloaded and the reception process is completed, the mail reception application 25 of the electronic mail transmitting / receiving apparatus 1 notifies the mail server of the completion of the mail reception operation. When the OK response indicating that the mail delivery operation end process has been completed is received in the mail server that has been transmitted (sequence Seq28) and received the end notification (sequence Seq29), the connection with the mail server is disconnected (sequence Seq30). .

  As described above, when the email transmission / reception device 1 performs an operation of receiving a mail for the email transmission / reception device 1 from the mail server, the email body (mail data) stored in the mail server is downloaded. Prior to the operation, first, only the header data of the mail is acquired, the “content type” recorded in the header data is analyzed, and the mail forms a single mail instead of a split mail. When it is confirmed that the mail is a normal mail, an operation of downloading the mail body (mail data) of the mail is performed for the first time. Thus, it is possible to reliably prevent invalid mail data from being downloaded from the mail server.

(Second operation example)
Next, another example of the operation of the e-mail transmission / reception apparatus 1 shown in FIGS. 1 and 2 will be described with reference to the flowchart of FIG. 4, the schematic diagram of FIG. 5, and the sequence chart of FIG. . Here, FIG. 6 is a sequence chart for explaining, as a second operation example, an operation sequence at the time of mail reception between the electronic mail transmitting / receiving apparatus 1 and the mail server, and is stored in the mail server (POP3). Among the emails for the electronic mail transmitting / receiving apparatus 1 (five emails in the present embodiment), the third and fifth emails are single emails as shown in FIG. However, the first, second, and fourth mails are divided into a plurality of, for example, three partial mail elements as shown in FIG. 5B. An example of the operation in the case of existing as mail is shown.

  4 and 5 are as described above, FIG. 4 is a flowchart for explaining an example of the flow of mail reception processing in the electronic mail transmitting / receiving apparatus 1, and FIG. 5 is stored in the mail server. It is a schematic diagram for demonstrating an example of the mail format which is.

  Here, in the second operation example shown in FIG. 6, as shown in the state of the mailbox in the sequence chart of FIG. 6, the mail for the electronic mail transmitting / receiving apparatus 1 is mail # 1, # 2,. , # 5, of which the first, second, and fourth mails # 1, # 2, and # 4 are split mails, and the third and fifth mails # 3 , # 5 indicates a case of normal mail.

That is, as shown in FIG. 5B, the first, second, and fourth mails # 1, # 2, and # 4 of the divided mails each have “Content-type: message / partial; ... "
Is displayed to indicate that it is a split mail and the split mail ID is
"Id =" X ";"
It is displayed as a partial mail element forming the same divided mail.

In addition, the division number and the total number of divisions of the first, second, and fourth mails # 1, # 2, and # 4 are as follows:
“Number = 1; total = 3;”
“Number = 2; total = 3;”
“Number = 3; total = 3;”
The total number of fragmented partial mail elements is 3, and each of the first, second, and fourth mails # 1, # 2, and # 4 is the first of the divided mails. It shows that it corresponds to the first, second, and third partial mail elements.

  In the sequence chart of FIG. 6, first, when the e-mail transmitting / receiving apparatus 1 is instructed to receive a mail by a user or at a predetermined time, the e-mail receiving application 25 is activated to start the sequence chart of FIG. As in the case of the sequences Seq1 to Seq5 in FIG. 5, after connecting to the mail server (POP3), a POP3 authentication request is executed, and when authentication is obtained, the mail is sent from the mail server to the electronic mail transmitting / receiving apparatus 1 The number of cases is acquired (sequence Seq31).

  The mail receiving application 25 of the electronic mail transmitting / receiving apparatus 1 that has received a notification that the number of mails stored in the mail box of the mail server is, for example, 5 is first prepared in the RAM 17 as preparation for receiving mail. Each flag (that is, the number of divided fragments, the divided mail searching status flag, and the divided abnormal status flag) is cleared and initialized (sequence Seq32).

  Thereafter, the mail receiving application 25 of the e-mail transmission / reception device 1 only includes the header data portion in ascending order of the e-mail number out of the number of e-mails for the e-mail transmission / reception device 1 stored in the mailbox. In order to perform reception, a download request for the header data of the first mail # 1, that is, a TOP1 command (header reception (mail # 1)) is transmitted to the mail server (sequence Seq33), from the mail server mailbox. The header data of the first mail # 1 is downloaded (sequence Seq34).

  When the download of the header data of the first mail # 1 is completed, the mail receiving application 25 of the electronic mail transmitting / receiving apparatus 1 analyzes the acquired header data of the first mail # 1 in the divided mail determination unit 251. (Sequence Seq35). An example of the header data analysis processing of the first mail # 1 in the divided mail determination unit 251 is as shown in the flowchart of FIG. 4 described above. That is, in the flowchart of FIG. 4, it is confirmed whether or not there is a display of “message / partial” indicating a divided mail in the “content type” of the acquired header data of the first mail # 1 (step S1).

  In the case of this operation example, as described above, the first mail # 1 is a divided mail and has a display of “message / partial” as shown in FIG. Then, it is determined that the message is a divided mail (Yes in step S1), and whether or not each partial mail element constituting the divided mail is being searched is determined with reference to the divided mail searching status flag. Determine (step S2). The split mail search in-progress flag is cleared at the stage of sequence Seq32 in FIG. 6 at the start of connection with the mail server and is in the “OFF” state (No in step S2). Is set to ON, that is, to indicate that the mode has shifted to the mode for searching for the remaining partial mail elements of the divided mail, the divided mail searching state flag is set to ON (step S10).

  Further, information (divided information) related to the divided mail included in the header data of the first mail # 1 is extracted and temporarily saved in the RAM 17 (step S11). Here, the information (divided information) related to the divided mail once saved is the title, the sender, the transmission date and time, the divided mail ID, the total number of divisions, the division number, and the like. Thereafter, the number of partial mail elements out of a plurality of partial mail elements constituting the divided mail indicated by the divided mail ID of the header data (in this operation example, the total number of divisions is three as described above). 6 is incremented with the number of divided fragments cleared at the stage of the sequence Seq32 in FIG. 6, and the number and division number of the mail currently being analyzed (the sequence Seq35 in FIG. 6). In this case, the number “1” indicating the first mail # 1 and the division number “1”) are temporarily saved in association with each other (step S4). As shown in the sequence Seq35 of FIG. 6, when the header data of the first mail # 1 is handled, it is the first partial mail element, and the incremented number of divided fragments is “1”. Become.

  After that, the total number of divisions (three in this operation example) of the header data of the first mail # 1 once saved in the RAM 17 is compared with the incremented number of divided pieces to determine whether they match. That is, regarding the divided mail indicated by the divided mail ID of the header data of the first mail # 1 temporarily saved in the RAM 17 as the partial mail element of the first detected divided mail, a plurality of partial mail elements are included. It is confirmed whether or not all have been detected (step S5).

  The sequence Seq35 in FIG. 6 is a stage in which the header data of the first partial mail element among the divided mails composed of three partial mail elements is handled as the total number of divisions, and the division total number has not yet been reached. Since there is no state (No in Step S5), the process proceeds to Step S6, and the mail whose header data is currently analyzed is stored in the mail server mailbox as the mail for the electronic mail transmitting / receiving apparatus 1. It is confirmed whether it is the last mail (that is, the fifth mail # 5 in this operation example) (step S6).

  The sequence Seq35 in FIG. 6 is a stage in which the header data of the first mail # 1 is handled, and the final mail (fifth mail # 5) has not yet been reached ( In step S6, No), in order to shift to the search operation for the remaining partial mail elements of the divided mail, the analysis processing of the header data of the first mail # 1 first detected as the divided mail is ended.

  Analysis processing of header data of the first mail # 1, that is, header data of the first partial mail element (the first detected partial mail element) of the divided mail with “X” as the divided mail ID 6 is completed, the mail receiving application 25 of the e-mail transmitting / receiving apparatus 1 in the sequence chart of FIG. 6 is stored in the mailbox because the divided mail searching status flag is “ON”. Out of the remaining number of mails for the electronic mail transmitting / receiving apparatus 1 (four in the present operation example), the same divided mail ID “X” as the first partial mail element is attached. Move on to search for the remaining partial mail elements.

  Here, in the case of this operation example, as described above, the next second mail # 2 is' X of the split mail ID of the first mail # 1 first detected as the partial mail element of the split mail. This is a partial mail element of a divided mail having the same divided mail ID as', and the state when the next partial mail element being searched is detected while the remaining partial mail elements constituting the divided mail are being searched. Explains.

  First, the second mail # 2 header data download request, that is, the TOP2 command (header reception (mail # 2)) is transmitted to the mail server (sequence Seq36), and the second mail # 2 is sent from the mail server mailbox. The header data of mail # 2 is downloaded (sequence Seq37).

  When the download of the header data of the second mail # 2 is completed, the mail receiving application 25 of the electronic mail transmitting / receiving apparatus 1 analyzes the acquired header data of the second mail # 2 in the divided mail determination unit 251. (Sequence Seq38). When the flowchart of FIG. 4 is activated as the analysis processing of the header data of the second mail # 2 in the divided mail determination unit 251, the “content type” of the acquired header data of the second mail # 2 is also displayed. It is confirmed whether or not there is a display of “message / partial” indicating a divided mail (step S1).

  In the case of this operation example, the second mail # 2 is also a divided mail as described above, and there is a display of “message / partial” as shown in FIG. Then, it is determined that it is a divided mail (Yes in step S1), and then whether or not each partial mail element constituting the first detected divided mail is in a state of being searched is determined as a divided mail searching state flag. (Step S2).

  The split mail search status flag is set to “ON” during the header data analysis processing of the first mail # 1, that is, when the first partial mail element of the split mail is detected (Yes in step S2). Next, out of the division information extracted and saved from the header data of the first mail # 1, that is, the header data of the first partial mail element of the divided mail, the divided mail ID 'X' is extracted, It is confirmed whether or not the divided mail ID of the second mail # 2 matches the divided mail ID “X” of the first mail # 1, that is, the partial mail element first detected as the divided mail (step). S3).

  If the divided mail ID of the second mail # 2 does not match the divided mail ID 'X' of the first detected partial mail element (No in step S3), the second mail # 2 Although it is a divided mail, at the time of the sequence Seq38, since the partial mail elements constituting the first detected divided mail are being searched, the second mail # 2 is in the currently searching state. Assuming that it does not correspond to the partial mail element constituting the first detected divided mail, the analysis processing of the header data of the second mail # 2 is terminated, and the next third mail # 3 Shift to header data download operation. In other words, even if partial mail elements of a divided mail having a different divided mail ID from the partial mail elements constituting the divided mail currently being searched are mixed in the mail server, the current search state Priority is given to the operation of searching all the partial mail elements constituting the split mail in the above.

  However, in this operation example, as described above, the divided mail ID of the second mail # 2 matches the divided mail ID “X” of the first detected partial mail element (step S3). Next, in order to count how many partial mail elements are detected as the partial mail elements constituting the first detected divided mail, the number of divided fragments is incremented and the current analysis processing is performed. Temporarily stored in a form in which the number of the mail being sent and the division number (in the case of the sequence Seq38 in FIG. 6, the number “2” indicating the second mail # 2 and the division number “2”) are associated with each other ( Step S4). As shown in the sequence Seq38 of FIG. 6, at the time when the header data of the second mail # 2 is handled, it is the second partial mail element, and the incremented number of divided fragments is “2”. Become.

  Thereafter, as in the case of the header data analysis process of the first mail # 1, the total number of divisions of the header data of the first mail # 1 once saved in the RAM 17 (three in this operation example) ) And the incremented number of divided fragments (step S5). At the stage of sequence Seq38 in FIG. 6, the second partial mail element header data is being handled. Since it has not reached (No in step S5), the process proceeds to step S6.

  The sequence Seq38 in FIG. 6 is a stage in which the header data of the second mail # 2 is handled, and the final mail (fifth mail # 5) has not yet been reached ( In step S6, No), in order to shift to the search operation of the remaining partial mail elements of the divided mail, the analysis processing of the header data of the second mail # 2 detected as the divided mail is ended.

  Analysis processing of the header data of the second mail # 2, that is, the second partial mail element (part detected as the second of three mails) of the split mail with “X” as the split mail ID When the analysis process of the header data of the mail element) is completed, in the sequence chart of FIG. 6, the mail receiving application 25 of the electronic mail transmitting / receiving apparatus 1 has the divided mail searching status flag set to “ON”. Of the remaining number of mails stored in the mailbox for the electronic mail transmitting / receiving apparatus 1 (the remaining three in this operation example), the same divided mail ID 'X' as the first partial mail element Moves to search for the last remaining partial mail element with '

  Here, in the case of this operation example, as described above, the next third mail # 3 is a normal mail that forms a single mail by one mail, and is a partial mail element that constitutes a split mail. The situation when a normal mail is detected while searching is described. First, a download request for header data of the third mail # 3, that is, a TOP3 command (header reception (mail # 3)) is transmitted to the mail server (sequence Seq39), and the third from the mailbox of the mail server. The header data of mail # 3 is downloaded (sequence Seq40).

  When downloading of the header data of the third mail # 3 is completed, the mail receiving application 25 of the electronic mail transmitting / receiving apparatus 1 analyzes the acquired header data of the third mail # 3 in the divided mail determination unit 251. (Sequence Seq41). As the analysis process of the header data of the third mail # 3 in the divided mail determination unit 251, when the flowchart of FIG. 4 is activated, the “content type” of the acquired header data of the third mail # 3 is also displayed. It is confirmed whether or not there is a display of “message / partial” indicating a divided mail (step S1).

  In the case of this operation example, the third mail # 3 is a normal mail as described above, and there is no “message / partial” display as shown in FIG. Assuming that it is not a divided mail (No in step S1), it is next determined whether or not each partial mail element constituting the divided mail is being searched with reference to the divided mail searching status flag. (Step S12).

  Since the divided mail search state flag is set to 'ON' during the header data analysis processing of the first mail # 1, that is, when the first partial mail element of the divided mail is detected (Yes in step S12), At present, it is assumed that each partial mail element constituting the divided mail detected first is in a search state, and the process proceeds to step S6.

  The sequence Seq41 in FIG. 6 is a stage in which the header data of the third mail # 3 is handled, and the final mail (fifth mail # 5) has not yet been reached ( In step S6, the header data analysis process for the third mail # 3 is terminated in order to shift to the search operation for the remaining partial mail elements of the divided mail being searched.

  When the partial mail element of the divided mail with “X” as the divided mail ID is being searched, the header data analysis processing of the third mail # 3, that is, the divided mail to be searched When the analysis processing of the normal mail header data which is not related to is completed, in the sequence chart of FIG. 6, the mail reception application 25 of the electronic mail transmitting / receiving apparatus 1 then sets the divided mail search status flag to “ON”. Therefore, out of the remaining number of mails stored in the mailbox for the electronic mail transmitting / receiving apparatus 1 (the remaining two are in this operation example), the same divided mail ID as the first partial mail element The operation proceeds to the operation of searching for the last partial mail element with “X”.

  Here, in the case of this operation example, as described above, the next fourth mail # 4 is “X” of the divided mail ID of the first mail # 1 first detected as the partial mail element of the divided mail. When the last partial mail element of the divided mail having the same divided mail ID as' is detected and the last partial mail element being searched is detected in the state of searching the last partial mail element constituting the divided mail Explaining the situation.

  First, a download request for header data of the fourth mail # 4, that is, a TOP4 command (header reception (mail # 4)) is transmitted to the mail server (sequence Seq42). The header data of mail # 4 is downloaded (sequence Seq43).

  When downloading of the header data of the fourth mail # 4 is completed, the mail receiving application 25 of the electronic mail transmitting / receiving apparatus 1 analyzes the acquired header data of the fourth mail # 4 in the divided mail determination unit 251. (Sequence Seq44). As the analysis process of the header data of the fourth mail # 4 in the divided mail determination unit 251, when the flowchart of FIG. 4 is started, the “content type” of the acquired header data of the fourth mail # 4 is also displayed. It is confirmed whether or not there is a display of “message / partial” indicating a divided mail (step S1).

  In the case of this operation example, as described above, the fourth mail # 4 is a divided mail and has a display of “message / partial” as shown in FIG. Then, it is determined that it is a divided mail (Yes in step S1), and then whether or not each partial mail element constituting the first detected divided mail is in a state of being searched is determined as a divided mail searching state flag. (Step S2).

  The split mail search status flag is set to “ON” during the header data analysis processing of the first mail # 1, that is, when the first partial mail element of the split mail is detected (Yes in step S2). Next, out of the division information extracted and saved from the header data of the first mail # 1, that is, the header data of the first partial mail element of the divided mail, the divided mail ID 'X' is extracted, It is confirmed whether or not the divided mail ID of the fourth mail # 4 matches the divided mail ID “X” of the partial mail element first detected as the first mail # 1, that is, the divided mail (step) S3).

  In this operation example, as described above, the divided mail ID of the fourth mail # 4 matches the divided mail ID 'X' of the partial mail element detected first (Yes in step S3). Next, in order to count how many partial mail elements are detected as the partial mail elements constituting the first detected divided mail, the number of divided fragments is incremented and the analysis process is currently being performed. The mail number and the division number (in the case of the sequence Seq44 in FIG. 6, the number “4” indicating the fourth mail # 4 and the division number “3”) are temporarily saved in association with each other (step S4). ). As shown in the sequence Seq44 of FIG. 6, at the time when the header data of the fourth mail # 4 is handled, it is the third partial mail element, and the incremented number of divided fragments is “3”. Become.

  Thereafter, as in the case of the header data analysis process of the first mail # 1, the total number of divisions of the header data of the first mail # 1 once saved in the RAM 17 (three in this operation example) ) And the incremented number of divided fragments (step S5), and in the sequence Seq44 of FIG. 6, the header data of the last third partial mail element is handled, Since it has reached the state (Yes in step S5), all partial mail elements having the same divided mail ID as 'X' of the divided mail ID of the first detected partial mail element have been detected. As shown in FIG.

  Here, at the stage of the sequence Seq44 in FIG. 6, the fifth mail # 5 still remains in the mail server as a mail that has not been analyzed for the header data of the mail for the electronic mail transmitting / receiving apparatus 1. However, all partial mail elements (three partial mail elements) having the same divided mail ID as 'X' of the divided mail ID of the partial mail element that was in the search state are detected, and the respective parts are detected. Since it has been found that the mail elements are the first mail # 1, the second mail # 2, and the fourth mail # 4 from the mail numbers 1, 2, and 4 sequentially saved in step S4. The header data analysis process is temporarily terminated, and the operation proceeds to the reception operation of the mail body (mail data) related to the divided mail.

  That is, in the flowchart of FIG. 4, the process proceeds to step S8 to clear the number of divided fragments in preparation for the analysis processing of the header data of the next divided mail (step S8), and further, the divided mail searching status flag is set. It is set to “OFF” and initialization is performed (step S9). As a result, the mail receiving application 25 of the electronic mail transmitting / receiving apparatus 1 shifts the split mail search in progress flag from “ON” to “OFF”, and the split abnormal state flag remains “OFF” and is “ON”. It is determined that all the partial mail elements composing the divided mail that was in the search state were detected normally, and proved as each partial mail element composing the divided mail. In order to perform the receiving operation of the mail body (mail data) of the first mail # 1, the second mail # 2, and the fourth mail # 4, the process proceeds to the sequence Seq45 of FIG.

  After shifting to the sequence Seq45, the mail receiving application 25 of the electronic mail transmitting / receiving apparatus 1 respectively includes the first mail # 1, the second mail # 2, and the fourth mail # 4 in step S4 of the flowchart of FIG. The order of the division numbers '1', '2', '3' saved in association with the mail number (in this operation example, as described above, the first mail # 1, second The mail body (mail data) download request (RETR) is sent to the mail server in the order of the second mail # 2 and the fourth mail # 4), and each mail body (mail data) is downloaded. When the reception process is completed, a deletion request (DELE) for each mail is sent to delete each mail from the mail server mailbox. That (sequence Seq45).

  That is, first, a mail data download request for mail # 1 (division number “1”), that is, a RETR1 command (reception (mail # 1)) is sent to the mail server, and mail # 1 (division is sent from the mail server mailbox. Download the mail data of number '1'). When the downloading of the mail data of mail # 1 (division number “1”) is completed and the reception process is completed, a deletion request for mail data of mail # 1 (division number “1”), that is, the DELE1 command (deletion (mail #) 1)) is sent to the mail server, the mail data of mail # 1 (partition number '1') is deleted from the mailbox, and the mail data of mail # 1 (partition number '1') is deleted. An OK response is received from the mail server.

  Next, a mail data download request of mail # 2 (division number “2”), that is, a RETR2 command (reception (mail # 2)) is sent to the mail server, and mail # 2 (division number) is sent from the mail server mailbox. Download the mail data of “2”). When the download of the mail data of mail # 2 (division number “2”) is completed and the reception process is completed, the mail data deletion request of mail # 2 (division number “2”), that is, the DELE2 command (deletion (mail #) 2)) is sent to the mail server, the mail data of mail # 2 (partition number '2') is deleted from the mailbox, and the mail data of mail # 2 (partition number '2') is deleted. An OK response is received from the mail server.

  Finally, a mail data download request for mail # 4 (division number “3”), that is, a RETR4 command (reception (mail # 4)) is sent to the mail server, and mail # 4 (division number) is sent from the mail server mailbox. Download the mail data of '3'). When the download of the mail data of mail # 4 (partition number “3”) is completed, and the three partial mail elements are combined into one mail as mail reception processing, the editing processing into a significant mail is completed. A mail data deletion request for mail # 4 (partition number '3'), that is, a DELE4 command (deletion (mail # 4)) is sent to the mail server, and mail data for mail # 4 (partition number '3') is sent to the mail. In addition to deleting from the box, an OK response indicating that the mail data of mail # 4 (division number “3”) has been deleted is received from the mail server.

  When the reception operation of the valid divided mail including all the partial mail elements is finished, the mail receiving application 25 of the electronic mail transmitting / receiving apparatus 1 next receives the electronic mail transmitting / receiving apparatus still remaining in the mail server mailbox. The operation shifts to mail receiving operation for No.1. In this operation example, the third mail # 3 and the fifth mail # 5 have not yet been downloaded and remain in the mailbox. Here, the third mail # 3 and the fifth mail # 5 are both normal mails, and the third mail is processed by the same sequence as the download operation described in the sequence chart of FIG. In the order of # 3 and fifth mail # 5, the download of the mail data and the mail reception process are carried out sequentially after the download of the respective header data, and then the respective mails in the mailbox are deleted. Processing is instructed (sequence Seq46).

  When all the mail data, for example, five mail data confirmed in the sequence Seq31 are downloaded and the reception process is completed, the mails of the e-mail transmitting / receiving apparatus 1 are the same as in the case of the sequences Seq28 to Seq30 in the sequence chart of FIG. When the reception application 25 transmits a mail reception operation end notification to the mail server and receives an OK response indicating that the mail delivery operation end processing has been completed from the mail server that has received the end notification, the reception application 25 connects to the mail server. Is cut (sequence Seq47).

  As described above, when the email transmission / reception device 1 performs an operation of receiving a mail for the email transmission / reception device 1 from the mail server, the email body (mail data) stored in the mail server is downloaded. Prior to the operation, first, only the header data of the mail is obtained, and the “content type” recorded in the header data is analyzed to confirm that the mail is a split mail. When all of the multiple partial email elements that make up the email are detected, and it is found that the mail body (mail data) that is valid as a divided mail is available on the mail server, the mail of the divided mail Download the main unit (mail data). Thus, the mail server downloads it as a valid split mail only when all the partial mail elements are available, and is ineffective as invalid mail data when the partial mail elements are not aligned. Do not execute the operation that downloads.

(Third operation example)
Next, a different example of the operation of the e-mail transmission / reception apparatus 1 shown in FIGS. 1 and 2 will be described with reference to the flowchart of FIG. 4, the schematic diagram of FIG. 5, and the sequence chart of FIG. . Here, FIG. 7 is a sequence chart for explaining, as a third operation example, an operation sequence at the time of mail reception between the electronic mail transmitting / receiving apparatus 1 and the mail server, and a plurality of parts constituting the divided mail. An example of the operation when the mail elements are irregular is shown.

  That is, in the third operation example, as shown in the mail box of the mail server (POP3) in the sequence chart of FIG. 7, the electronic mail transmission / reception apparatus 1 stored in the mail server (POP3). 3rd, 4th and 5th emails form a single email as shown in FIG. 5 (A) among the emails destined for (5 emails in this embodiment) The remaining first and second mails # 1 and # 2 are divided mails divided into a plurality of, for example, three partial mail elements as shown in FIG. 5B. However, the first and second partial mail elements are present as the first and second mails # 1 and # 2 among the three main divided mails with the total number of divisions. The third partial mail element is the mail server Not be present in the chromatography mailbox, incomplete (partial mail elements irregular state) shows an example of the operation when in the as partial email.

  Thus, as shown in the state of the mailbox in the sequence chart of FIG. 7, the mail is in an incomplete state (partial mail elements are not aligned), as shown in the sequence chart of FIG. 7. If there is a split mail, the e-mail transmitting / receiving apparatus 1 deletes it from the mailbox of the mail server (POP3) without receiving the mail body (mail data) of the partial mail element related to the split mail. The example which operates is shown.

  4 and 5 are as described above, FIG. 4 is a flowchart for explaining an example of the flow of mail reception processing in the electronic mail transmitting / receiving apparatus 1, and FIG. 5 is stored in the mail server. It is a schematic diagram for demonstrating an example of the mail format which is.

  Here, in the third operation example shown in FIG. 7, as described above, there are five mails # 1, # 2,... The second and second mails # 1 and # 2 are the first and second partial mail elements of the split mail composed of three partial mail elements, the third, fourth, and fifth. Mails # 3, # 4, and # 5 are normal mails that form a single mail.

As shown in FIG. 5B, each of the first and second mails # 1 and # 2 of the divided mail has a “content type” of “Content-type: message / partial;
Is displayed to indicate that it is a split mail and the split mail ID is
"Id =" X ";"
It is displayed as a partial mail element forming the same divided mail.

Also, the division number and the total number of divisions of the first and second mails # 1 and # 2 are as follows:
“Number = 1; total = 3;”
“Number = 2; total = 3;”
The total number of fragmented partial mail elements is three, and the first and second mails # 1 and # 2 are the first and second of the divided mails, respectively. Although it corresponds to the partial mail element, it indicates that the third partial mail element does not exist in the mail server mailbox.

  In the sequence chart of FIG. 7, first, when an e-mail transmission / reception apparatus 1 is instructed to receive a mail by a user or at a predetermined time, the e-mail receiving application 25 is activated and the sequence chart of FIG. As in the case of the sequences Seq1 to Seq5 in FIG. 5, after connecting to the mail server (POP3), a POP3 authentication request is executed, and when authentication is obtained, the mail is sent from the mail server to the electronic mail transmitting / receiving apparatus 1 The number of cases is acquired (sequence Seq51).

  The mail receiving application 25 of the electronic mail transmitting / receiving apparatus 1 that has received a notification that the number of mails stored in the mail box of the mail server is, for example, 5 is first prepared in the RAM 17 as preparation for receiving mail. Each flag (that is, the number of divided fragments, the divided mail searching state flag, and the divided abnormal state flag) is cleared and initialized (sequence Seq52).

  Thereafter, the mail receiving application 25 of the e-mail transmission / reception device 1 only includes the header data portion in ascending order of the e-mail number out of the number of e-mails for the e-mail transmission / reception device 1 stored in the mailbox. It will receive. Here, the first mail # 1 and the second mail # 2 are both divided mails, and the first mail # 1 and the second mail # described in the sequence chart of FIG. Each header data is downloaded sequentially in the order of the first mail # 1 and the second mail # 2 by the same sequence as the download operation of No. 2. As the analysis result of each header data, the first partial mail element and the second partial mail element of the divided mail composed of three divided totals are detected, the number of divided fragments is incremented to “2”, and then continued. Thus, in order to search for the last third partial mail element, the analysis of the header data after the third mail # 3 is continued while the divided mail search state flag is set to “ON”. .

  That is, the mail receiving application 25 of the electronic mail transmitting / receiving apparatus 1 first transmits a header data download request of the first mail # 1, that is, a TOP1 command (header reception (mail # 1)) to the mail server ( Sequence Seq53), the header data of the first mail # 1 is downloaded from the mailbox of the mail server (sequence Seq54).

  When the download of the header data of the first mail # 1 is completed, the mail receiving application 25 of the electronic mail transmitting / receiving apparatus 1 analyzes the acquired header data of the first mail # 1 in the divided mail determination unit 251. (Sequence Seq55). In the case of this operation example, as described above, since the first mail # 1 is the first detected divided mail, the divided mail determination unit 251 of the mail receiving application 25 of the electronic mail transmitting / receiving apparatus 1 The first mail # 1 detects that it is the first partial mail element of the divided mail having the divided mail ID “X” and the total number of divided mails, and information about the divided mail (divided information) ) And the correspondence relationship between the mail number and the division number are temporarily saved in the RAM 17, the division mail search in progress flag is set to “ON”, and the number of division fragments is incremented to “1”.

  Thereafter, the mail receiving application 25 of the electronic mail transmitting / receiving apparatus 1 downloads the header data of the second mail # 2 in order to search for the remaining partial mail elements of the divided mail whose divided mail ID is “X”. By sending a request, that is, a TOP2 command (header reception (mail # 2)) to the mail server (sequence Seq56), the header data of the second mail # 2 is downloaded from the mail server mailbox (sequence Seq57).

  When the download of the header data of the second mail # 2 is completed, the mail receiving application 25 of the electronic mail transmitting / receiving apparatus 1 analyzes the acquired header data of the second mail # 2 in the divided mail determination unit 251. (Sequence Seq58). In the case of this operation example, as described above, since the second mail # 2 is a partial mail element of a divided mail having the same divided mail ID 'X' as the first mail # 1, the electronic mail The divided mail determination unit 251 of the mail reception application 25 of the transmission / reception apparatus 1 has the second divided mail ID “X” that is the same as the first mail # 1 that is first detected as the divided mail. The second partial mail element is detected, and the number of divided fragments is incremented to “2” while the divided mail search state flag remains “ON”.

  After that, the mail receiving application 25 of the electronic mail transmitting / receiving apparatus 1 downloads the header data of the third mail # 3 in order to search for the last partial mail element of the divided mail with the divided mail ID “X”. By sending a request, that is, a TOP3 command (header reception (mail # 3)) to the mail server (sequence Seq59), the header data of the third mail # 3 is downloaded from the mail server mailbox (sequence Seq60).

  When downloading of the header data of the third mail # 3 is completed, the mail receiving application 25 of the electronic mail transmitting / receiving apparatus 1 analyzes the acquired header data of the third mail # 3 in the divided mail determination unit 251. (Sequence Seq61). In the case of this operation example, as described above, the third mail # 3 is not a split mail but a normal mail, and the split mail search status flag is “ON”. Since the search is in progress, the third mail # 3, which is a normal mail not related to the divided mail to be searched, is ignored, and the header data download operation for the next fourth mail # 4 is ignored. Migrate to

  However, in this operation example, both the next fourth mail # 4 and the last fifth mail # 5 are normal data, and the divided mail whose search target divided mail ID is “X”. The last third partial mail element cannot be detected. That is, the mail receiving application 25 of the electronic mail transmitting / receiving apparatus 1 downloads the header data of the fourth mail # 4 in order to search for the last partial mail element of the divided mail whose divided mail ID is “X”. That is, by sending a TOP4 command (header reception (mail # 4)) to the mail server (sequence Seq62), the header data of the fourth mail # 4 is downloaded from the mail server mailbox (sequence Seq63).

  When downloading of the header data of the fourth mail # 4 is completed, the mail receiving application 25 of the electronic mail transmitting / receiving apparatus 1 analyzes the acquired header data of the fourth mail # 4 in the divided mail determination unit 251. (Sequence Seq64). In the case of this operation example, since the fourth mail # 4 is also a normal mail, the fourth mail # 4 is ignored, and the header data of the next fifth mail # 5 is downloaded. Transition.

  The mail receiving application 25 of the electronic mail transmitting / receiving apparatus 1 searches for the header data of the fifth mail # 5, that is, TOP5 in order to search for the last partial mail element of the divided mail whose divided mail ID is “X”. By sending a command (header reception (mail # 5)) to the mail server (sequence Seq65), the header data of the fifth mail # 5 is downloaded from the mail server mailbox (sequence Seq66).

  When the download of the header data of the fifth mail # 5 is completed, the mail receiving application 25 of the electronic mail transmitting / receiving apparatus 1 analyzes the acquired header data of the fifth mail # 5 in the divided mail determination unit 251. (Sequence Seq67). In the case of this operation example, the fifth mail # 5 is also a normal mail, but the mail is being searched even though the divided mail search status flag is set to “ON”. This is the last mail for the electronic mail transmitting / receiving apparatus 1 stored in the server mailbox.

  Therefore, as shown in step S6 of the flowchart of FIG. 4, the divided mail determination unit 251 acquires the fifth mail # 5 as the number of mails for the electronic mail transmitting / receiving apparatus 1 in the sequence Seq51 of FIG. If it is determined that it is the last mail among the five mails (Yes in step S6), the last partial mail element constituting the divided mail being searched, that is, the third partial mail element cannot be detected. It is determined that there is an incomplete divided mail (a divided mail whose partial mail elements are not uniform), and the division abnormal state flag is set to “ON” (step S7). Thereafter, in preparation for the analysis processing of the header data of the next divided mail, the number of divided fragments is cleared (step S8), and the divided mail searching status flag is set to “OFF” to perform initialization (step S8). Step S9).

  As a result, the mail receiving application 25 of the electronic mail transmitting / receiving apparatus 1 shifts the divided mail search state flag from “ON” to “OFF” and the divided abnormal state flag is “OFF” in the sequence Seq68 of FIG. Confirmed that it has shifted from 'ON' to 'ON' and the search status of the split mail has been completed, but all the partial mail elements composing the split mail that were in the search state could not be detected Judge that it is. Thus, in such a case, the mail receiving application 25 of the electronic mail transmitting / receiving apparatus 1 makes the first mail # 1 and the second mail # known as the partial mail elements constituting the divided mail. 2. Is it possible to activate the split mail deletion permission determination unit 252 and delete the mail body (mail data) of the mail server 2 from the mailbox of the mail server without performing the download operation to the electronic mail transmitting / receiving apparatus 1 of FIG. It is determined whether or not (sequence Seq68). If it is determined that it can be deleted, the process proceeds to sequence Seq69.

  In the sequence Seq69, the divided mail with the divided mail ID 'X' is assumed to be an invalid mail with partial mail elements being irregular, and the first and second partial mail elements constituting the first and second partial mail elements are included. Mail # 1 and second mail # 2 in that order, the mail data deletion request of mail # 1 (division number '1'), that is, the DELE1 command (deletion (mail # 1)), mail # 2 (division number) '2') mail data deletion request, that is, a DELE2 command (deletion (mail # 2)) is sequentially sent to the mail server, and mail # 1 (division number '1'), mail # 2 (division number '2') ) Is deleted from the mailbox, and an OK response indicating that the mail data of mail # 1 (division number “1”) and mail # 2 (division number “2”) has been deleted, respectively. The sequentially by receiving from the mail server, to verify that the partial write element is removed from all mailbox mail data irregular division mail (sequence Seq69).

  When the deletion operation from the mail server of the first mail # 1 and the second mail # 2 regarding the uneven divided mails is finished, the mail receiving application 25 of the electronic mail transmitting / receiving apparatus 1 next sends the mail of the mail server. The operation shifts to a mail receiving operation for the electronic mail transmitting / receiving apparatus 1 still remaining in the box. In this operation example, the third mail # 3, the fourth mail # 4, and the fifth mail # 5 are still in the mailbox without being downloaded yet.

  Here, the third mail # 3, the fourth mail # 4, and the fifth mail # 5 are all normal mails, and the same sequence as the download operation described in the sequence chart of FIG. The third mail # 3, the fourth mail # 4, and the fifth mail # 5 are sequentially downloaded in the order of the header data and then the mail data is downloaded and the mail is received. The process is executed, and thereafter, the deletion process of each mail in the mailbox is instructed (sequence Seq70).

  When the mail reception operation regarding the number of mails confirmed in the sequence Seq51, for example, all the mail data for five, is completed, the mail reception application of the electronic mail transmitting / receiving apparatus 1 is the same as the case of the sequences Seq28 to Seq30 in the sequence chart of FIG. 25 sends a mail reception operation end notification to the mail server, and disconnects the connection to the mail server upon receiving an OK response indicating that the mail distribution operation end processing has been completed from the mail server that received the end notification. (Sequence Seq71).

  After that, when the mail receiving application 25 of the electronic mail transmitting / receiving apparatus 1 confirms that the division abnormal state flag is in the “ON” state, the divided mail with the divided mail ID “X” to be subjected to the reception process. Because the partial mail elements are not uniform, a divided mail abnormality notification indicating that the partial mail has been deleted without being received is transmitted in a mail format to the sender of the divided mail (sequence) Seq72).

  In this operation example, after completing the receiving operation for all cases and disconnecting from the mail server, it is checked whether the split abnormal state flag is 'ON' or not. In this case, the example in which the divided mail abnormality notification is transmitted to the sender has been described. For example, when it is determined in the sequence Seq68 in FIG. A divided mail abnormality notification may be transmitted to the mail, and after the division mail abnormality notification is transmitted, the division abnormality state flag may be initialized to an “OFF” state. This is a case where the divided mail different from the divided mail ID “X” exists in the mail for the electronic mail transmitting / receiving apparatus 1 still remaining in the mail server mailbox by performing the operation as described above. However, in the subsequent mail reception operation, the divided mail reception process can be performed.

  Also, the split mail error notification sent to the sender of the split mail in order to notify that the split mail with the partial mail element irregularity has been deleted from the mail server is the subject of deletion by the sender of the split mail. In order to make it easy to understand which split mail has become the partial mail element (that is, fragmented split mail with header information or split number '1' of the split mail to be deleted) It is desirable to add and notify as much as possible the mail text included in the first partial mail element).

  Here, the header information of the split mail to be deleted to be added to the split mail abnormality notification is detected first by the split mail determination unit 251 as shown in step S11 of the flowchart of FIG. The division information (title, sender, transmission date / time, division mail ID, division total number, division number, etc.) regarding the division mail included in the header data of the division mail is saved in the RAM 17. Therefore, by using the saved division information, the mail transmission application 26 of the electronic mail transmission / reception apparatus 1 creates, for example, a mail as shown in the table of FIG. What is necessary is just to make it transmit with respect to the transmission source of the said division | segmentation mail. FIG. 8 is a table showing an example of the mail format of the divided mail abnormality notification mail to be transmitted to the sender of the divided mail to be deleted.

  The split mail error notification mail shown in Fig. 8 says, "Since the following split mail that you sent was split into multiple partial mail elements for some reason, the mail did not reach the mail server. In this example, the transmission date and time 311 and the title 312 are described after the warning message 310 indicating that the message has been deleted by the receiver. The split mail abnormality notification mail is not limited to the example of FIG. 8 and notifies the receiving side e-mail transmission / reception device 1 that the split mail that was sent was abnormal and thus was not received. Any content can be used as long as it is possible.

  In addition, the split mail sender that received the split mail error notification mail will be able to easily understand the split mail that has been deleted and has not reached the split mail from the mail server mailbox. Before deleting, for example, the mail corresponding to the first partial mail element, for example, the mail data (the mail body) of the first mail # 1 is downloaded, and the mail transmission application 26 is used for the divided mail abnormality notification. When composing a mail, send the mail data (mail body) of the first mail # 1 as an attached file, or add a part of it to the text of the split mail error notification mail. May be.

  Furthermore, the divided mail abnormality notification is not only transmitted as a divided mail abnormality notification mail to the transmission source of the divided mail, but also displayed on the display unit 13 of the electronic mail transmitting / receiving apparatus 1 which is the divided mail receiving side. It may be displayed so as to notify the user of the e-mail transmitting / receiving apparatus 1 or the display unit 13 of the e-mail transmitting / receiving apparatus 1 without transmitting it to the transmission source of the divided mail. You may make it display on a screen only.

  As described above, when the email transmission / reception device 1 performs an operation of receiving a mail for the email transmission / reception device 1 from the mail server, the email body (mail data) stored in the mail server is downloaded. Prior to the operation, first, only the header data of the mail is obtained, and the “content type” recorded in the header data is analyzed to confirm that the mail is a split mail. If all of the partial mail elements that make up the mail are searched in the mail server, and all of the partial mail elements cannot be detected, the mail is not uniform It is determined that there is invalid mail data in the mail server, and the invalid invalid mail data that make up the split mail Without having to download, perform the operation to be deleted from the mail server. Thus, it is possible to reliably prevent invalid mail data from being downloaded from the mail server to the e-mail transmitting / receiving apparatus 1 like a divided mail in which partial mail elements are irregular. it can.

(Fourth operation example)
Next, further different examples of the operation of the e-mail transmitting / receiving apparatus 1 shown in FIGS. 1 and 2 are shown in the flowchart of FIG. 4, the schematic diagram of FIG. 5, the sequence chart of FIG. 9, and the flowchart of FIG. Will be described. Here, FIG. 9 is a sequence chart for explaining, as a fourth operation example, an operation sequence at the time of mail reception between the electronic mail transmitting / receiving apparatus 1 and the mail server, and a plurality of parts constituting divided mail. An operation example different from the third operation example of FIG. 7 of the operation when the mail elements are irregular is shown. FIG. 10 is a flowchart for explaining an example of the flow of processing for determining whether or not a divided mail can be deleted in the electronic mail transmitting / receiving apparatus 1, and shows an example of the operation of the divided mail deletion determination unit 252.

  In other words, in the fourth operation example, as shown in the mail box of the mail server (POP3) in the sequence chart of FIG. 9, as in the case of FIG. 7 in the third operation example, the mail server ( Of the mails (5 mails in this embodiment) for the electronic mail transmitting / receiving apparatus 1 stored in POP3), the third, fourth, and fifth mails are shown in FIG. Is a normal mail that forms a single mail as shown in FIG. 5, and the remaining first and second mails # 1 and # 2 are a plurality of mails as shown in FIG. It was a divided mail divided into three partial mail elements. Of the three divided mails, the first and second partial mail elements are the first and second mails among the three divided mails. Although it exists as # 1, # 2, the last The third part mail elements not present in the mail server mailbox, incomplete (partial mail elements irregular state) shows an example of the operation when in the as partial email.

  Thus, as shown in the state of the mailbox in the sequence chart of FIG. 9, the mail is in an incomplete state (partial mail elements are not aligned) as mail for the electronic mail transmitting / receiving apparatus 1. Even in the case where there is a divided mail, the electronic mail transmitting / receiving apparatus 1 in the fourth operation example, a specific determination process relating to the deletion feasibility determination of the sequence Seq68 in FIG. 7 of the third operation example. As an example, as illustrated in the flowchart of FIG. 10, the mail data related to the divided mail is immediately determined to be deleteable and is not immediately deleted from the mail server (POP3) mailbox. It is determined whether or not a predetermined condition is established as a deletion suspension condition, and if the deletion suspension condition is established, a deletion operation is performed. It shows the case which operates to hold Dan.

  4 and 5 are as described above, FIG. 4 is a flowchart for explaining an example of the flow of mail reception processing in the electronic mail transmitting / receiving apparatus 1, and FIG. 5 is stored in the mail server. It is a schematic diagram for demonstrating an example of the mail format which is.

  Here, also in the fourth operation example shown in FIG. 9, as in the case of the third operation example, as described above, the mail for the electronic mail transmitting / receiving apparatus 1 is mail # 1, # 2,. # 5, the first and second mails # 1 and # 2 are the first and second partial mail elements of the split mail composed of three partial mail elements, The third, fourth, and fifth mails # 3, # 4, and # 5 are normal mails that form a single mail.

  Therefore, the operations from sequence Seq81 to Seq97 in the sequence chart of FIG. 9 are exactly the same as the operations from sequence Seq51 to Seq67 in the sequence chart of FIG. 7 described as the third operation example. The description will be omitted, and the sequence after the deletion determination operation of the sequence Seq98 will be described.

  In the sequence Seq98 of FIG. 9, the mail receiving application 25 of the electronic mail transmitting / receiving apparatus 1 shifts the split mail search status flag from “ON” to “OFF”, and the split abnormal status flag is changed from “OFF” to “ON”. Confirming that it has shifted to ', the search status of the split mail has ended, but it has been determined that all the partial mail elements that make up the split mail that was in the search state could not be detected To do. Thus, in such a case, the mail receiving application 25 of the electronic mail transmitting / receiving apparatus 1 makes the first mail # 1 and the second mail # known as the partial mail elements constituting the divided mail. The divided mail deletion permission determination unit 252 is activated without performing the download operation of the mail data (mail main body) 2 to determine whether or not the mail data can be deleted from the mail server mailbox (sequence Seq98). ).

  An example of a specific determination method of deletion possibility in the divided mail deletion possibility determination unit 252 is shown in the flowchart of FIG. 10 described above. That is, in the flowchart of FIG. 10, the elapsed time from the transmission time when the target divided mail is transmitted from the transmission source is determined in advance as a predetermined deletion suspension condition for determining whether to delete or temporarily hold. This example illustrates the use of whether or not a first predetermined elapsed time such as X minutes has elapsed, and holds the deletion from the mail server until the first predetermined elapsed time such as X minutes elapses. Shows the case.

  That is, when the flowchart of FIG. 10 is activated, first, information on the transmission date and time described in the header data of the target divided mail is obtained from the header information temporarily saved in step S11 of FIG. The transmission date and time, that is, the transmission time from the transmission source, and the current time measured by the RTC 14 in the electronic mail transmission / reception apparatus 1 are compared (step S21). If the current time measured by the RTC 14 has passed a predetermined first predetermined elapsed time, for example, X minutes from the transmission time from the transmission source (Yes in step S22), deletion of the divided mail is deleted. Outputs permission.

  On the other hand, when the current time measured by the RTC 14 has not reached the first predetermined elapsed time, for example, X minutes, determined in advance from the transmission time from the transmission source (No in step S22), Assuming that deletion is impossible, the deletion of the divided mail is suspended, and the remaining time, for example, Y minutes obtained by subtracting the transmission time from the current time is calculated, and the remaining time Y is saved in the RAM 17 (step S24).

  Note that the first predetermined elapsed time, for example, X minutes, may be set as a fixed value by the e-mail transmission / reception apparatus 1, or prepared in the FLASH memory 18 or the like and the e-mail transmission / reception apparatus 1. The setting value may be held in a format that can be rewritten by the user.

  When the mail receiving application 25 of the electronic mail transmitting / receiving apparatus 1 determines that the mail can be deleted as a result of determining whether the divided mail can be deleted or not in the divided mail deleting permission determining unit 252, the process proceeds to the sequence Seq99 in FIG. Then, as a third operation example, the operations of the sequences Seq69 to Seq72 shown in FIG. 7 are performed to forcibly delete the mail data of the divided mail whose partial mail elements are not uniform from the mail server mailbox, After receiving the remaining mail, disconnect the connection with the mail server, and then indicate to the sender of the split mail that it has been deleted without being sent to the receiver. The division mail abnormality notice is transmitted in the mail format (sequence Seq99).

  On the other hand, as a result of determining whether or not the divided mail can be deleted, the deletion cannot be performed until the remaining time obtained by subtracting the transmission time from the current time, for example, Y minutes has elapsed, and the deletion operation is performed. If it is determined that the mail is suspended, the mail receiving application 25 of the electronic mail transmitting / receiving apparatus 1 moves to the sequence Seq100, and once with the mail server in the same procedure as the sequence Seq27 to Seq30 in FIG. After completing the mail receiving operation, the connection with the mail server is disconnected (sequence Seq100).

  Thereafter, when the remaining time, for example, Y minutes elapses, the mail receiving application 25 of the e-mail transmitting / receiving apparatus 1 automatically performs the same procedure as in the case of the sequences Seq1 to Seq5 in the sequence chart of FIG. After the connection with POP3), a POP3 authentication request is executed, and when authentication is obtained, an operation of acquiring the number of mails for the electronic mail transmitting / receiving apparatus 1 from the mail server is performed, and then the sequence Seq82 When it is detected that all the partial mail elements constituting the divided mail are prepared by repeating the operation of searching for the partial mail elements of the divided mail such as up to Seq97, the divided mail is divided in the same manner as the sequences Seq45 to Seq47 in FIG. Receiving processing of all the partial mail elements that compose the mail (download, partial (Receiving and deleting mail elements such as editing a mail element), and then receiving the remaining normal mail that remains in the mail server, and then disconnecting the mail server. (Sequence Seq101).

  On the other hand, if it is detected that the partial mail elements constituting the divided mail are not aligned even after the remaining time, for example, Y minutes have elapsed, it is determined that the divided mail is an abnormal divided mail. As with the sequence Seq99, the mail data of the divided mails with partial partial mail elements are forcibly deleted from the mail server mailbox, and after receiving the remaining mail, the connection with the mail server is disconnected. The operation is performed, and thereafter, a divided mail abnormality notice indicating that the divided mail has been deleted without being transmitted to the receiving side is transmitted in a mail format to the transmission source of the divided mail (sequence Seq101).

  As described above, when the email transmission / reception device 1 performs an operation of receiving a mail for the email transmission / reception device 1 from the mail server, the email body (mail data) stored in the mail server is downloaded. Prior to the operation, first, only the header data of the mail is obtained, and the "content type" recorded in the header data is analyzed to confirm that the mail is a split mail. As a result of performing an operation to search whether all of the multiple partial mail elements that make up the mail exist in the mail server, all of the multiple partial mail elements that make up the split mail Even if it cannot be detected, it will be deleted from the mail server as long as the predetermined deletion hold condition is satisfied. Pending, at the time the deletion pending condition is not established, the first time, operates to remove the division mail from a mail server as an invalid write data irregular.

  Thus, as if the mail server was in the process of receiving the remaining partial mail elements of the split mail, all the partial mail elements were placed in the mailbox while the deletion hold condition was satisfied. Can be quickly received as an effective divided mail by the e-mail transmission / reception apparatus 1 on the receiving side, but only when the deletion hold condition is not satisfied, Since the divided mail with the irregular mail elements is deleted from the mail server, it is possible to reliably prevent the mail data that is not valid from being downloaded from the mail server from being wastedly downloaded to the electronic mail transmitting / receiving apparatus 1. .

(Description of the effect of this embodiment)
As described in detail above, according to the present embodiment, the following effects can be obtained.

  The first effect is that when there is a divided mail in the mail server where not all of the divided partial mail elements are prepared for some reason, the electronic mail transmitting / receiving apparatus 1 is not effective because the partial mail elements are not aligned. Since the operation of receiving the divided mail that is not present is not performed, it is possible to reliably prevent a situation in which the memory resource of the electronic mail transmitting / receiving apparatus 1 is compressed. Possible causes for the partial mail elements of the split mail to be irregular are, for example, when they are attacked maliciously, or when they are not delivered due to a failure such as a failure on the communication network side for mail delivery, etc. Is done.

  The second effect is that the partial mail elements are not uniform and the divided mail that is not valid is automatically deleted from the mail server, so that the operator does not need to manually delete the divided mail from the mail server. There is in doing. In addition, since a mechanism is used to notify the email sender / receiver of the email that the email has been deleted from the mail server, the split email is known by the sender / receiver user. It does not disappear in the meantime, and the sender and receiver of the divided mail can take some measures.

(Configuration example of other embodiment)
Next, another example of the configuration of the electronic mail transmitting / receiving apparatus according to the present invention will be described. FIG. 11 is a block diagram showing another example of the block configuration of the e-mail transmission / reception apparatus according to the present invention. As a hardware configuration of the e-mail transmission / reception apparatus, the e-mail transmission / reception shown in FIG. The case where RTC14 with which the apparatus 1 was equipped does not exist is shown.

  That is, the electronic mail transmitting / receiving apparatus 1A shown in FIG. 11 includes a main control unit 11 that controls the entire apparatus, an operation unit 12 that is operated by a user, a display unit 13 that displays information on a screen, and a LAN (Local Area Network) line. LAN controller 15 for controlling the memory, ROM (Read Only Memory) 16 for storing fixed information such as control programs and system data, RAM (Random Access Memory) 17 for temporarily storing various data, and nonvolatile memory However, there is no RTC (Real Time Clock) for measuring the current time.

  11 will be described in terms of functional aspects. The configuration is the same as that of FIG. 2 described above, and each functional element is realized by a control program stored in the ROM 16, and the electronic mail. The transmission / reception device 1A includes at least functional elements of a LAN controller driver 21, a TCP / IP protocol stack 22, a POP3 client 23, an SMTP client 24, a mail reception application 25, and a mail transmission application 26. The mail receiving application 25 includes at least a divided mail determination unit 251 and a divided mail deletion availability determination unit 252.

  However, in the electronic mail transmitting / receiving apparatus 1A of FIG. 11 that does not include an RTC that measures the current time, the split mail deletion permission determination unit 252 determines whether or not to delete a split mail based on whether or not a deletion suspension condition is satisfied. In this case, the current time as in steps S21 and S22 in FIG. 10 cannot be used. Therefore, during the mail receiving operation from the mail server of the electronic mail transmitting / receiving apparatus 1A, for example, any partial mail element of the divided mail divided into a plurality of partial mail elements in the header analysis in the sequence 97 of FIG. For example, a timer may be started at the time when it is detected that the divided mail is not uniform. As described above, when the timer is started, the mail reception operation with the mail server is once terminated by the procedure shown in the sequence 27 to Seq30 in FIG. 3 and then connected to the mail server. After that, the electronic mail transmitting / receiving apparatus 1A shifts to a state in which it is monitored whether or not the timer has counted a predetermined second predetermined elapsed time, for example, X ′ minutes.

  Then, when the timer counts to the second predetermined elapsed time, for example, X ′ minutes, the mail receiving application 25 of the electronic mail transmitting / receiving apparatus 1A automatically performs the case of sequences Seq1 to Seq5 in the sequence chart of FIG. If the connection with the mail server (POP3) is performed again in the same procedure as described above, and then the search operation for the divided mail that is not complete is repeated in the procedure such as the sequence Seq82 to Seq97 in FIG. good.

  That is, when the timer counts to the second predetermined elapsed time, for example, X ′ minutes, the mail receiving application 25 of the electronic mail transmitting / receiving apparatus 1A reconnects to the mail server (POP3), and then performs POP3 authentication. When the request is executed and the authentication is obtained, an operation for obtaining the number of mails for the electronic mail transmitting / receiving apparatus 1 from the mail server is performed, and then, for example, divided mails such as sequences Seq82 to Seq97 in FIG. When it is detected that all the partial mail elements constituting the divided mail are prepared, all the parts constituting the divided mail are similar to the sequences Seq45 to Seq47 in FIG. Mail element reception processing (downloading, partial mail element editing processing, etc.) After performing removal processing), further, after performing reception processing of the remaining mail remaining in the mail server, performs the cutting operation of the connection to the mail server.

  On the other hand, if it is detected that the partial mail elements constituting the divided mail are not aligned even when the timer counts to the second predetermined elapsed time, for example, X ′ minutes, the divided mail is an abnormal divided mail. In the same way as the sequence Seq99 in FIG. 9, the mail data of the divided mail whose partial mail elements are not uniform are forcibly deleted from the mail server mailbox and the remaining mail is received. Then, the connection with the mail server is disconnected, and then the split mail error notification indicating that the mail was deleted without being sent to the receiving side is sent to the split mail sender. Send with.

  Thus, in the present embodiment, when it is detected in the mail receiving operation that the partial mail elements constituting the divided mail are not uniform, a timer is used instead of using the RTC that measures the current time. This is a case where the current time cannot be accurately measured by automatically reconnecting with the mail server according to the time measured by the timer and repeating the divided mail search operation. In other words, the same effect as in the case where the RTC exists can be obtained.

(Further different embodiments)
Further, a first example of a different embodiment is a first predetermined process for determining whether or not a divided mail can be deleted in the divided mail deletion determination section 252 when the RTC 14 is provided as in the electronic mail transmitting / receiving apparatus 1 of FIG. A time, for example, X minutes, or a second predetermined elapsed time, for example, X ′ minutes, for determining whether or not to delete a divided mail that is checked against a time measured by a timer when the RTC 14 is not provided as in the electronic mail transmitting / receiving apparatus 1A of FIG. It is about the setting about.

The value of the first predetermined elapsed time, for example, X minutes or the second predetermined elapsed time, for example, X ′ is determined by the electronic mail transmitting / receiving device 1, 1A on the receiving side of the divided mail in each of the above-described embodiments. Although an example of setting is shown, a value specified on the transmission side of the divided mail may be set. That is, as shown in the configuration example of the header part of the split mail in FIG. 12, when creating a split mail on the transmission side, as an extension header of the header part of the split mail, for example,
"X-divmail-susp: 2"
The predetermined elapse time designation information 410 (in this example, 2 minutes is designated as X minutes) for determining whether or not the divided e-mail can be deleted is inserted, and the division e-mail in which the predetermined elapse time designation information 410 is inserted as an extension header is transmitted. You may make it do. FIG. 12 is a table showing an example of a mail format in which predetermined elapse time designation information 410 for determining whether or not a divided mail can be deleted is inserted into the header of the divided mail.

  In a state in which the divided mail in which the predetermined elapsed time specifying information 410 for determining whether or not to delete the divided mail is inserted as an extension header is stored in the mail server mailbox, When downloading the header data of the divided mail from the mail server by the mail receiving operation, the divided mail determination unit 251 of the mail receiving application 25 of the electronic mail transmitting / receiving device 1 or 1A uses the header information in step S11 of FIG. Is stored in the RAM 17 together with the predetermined elapsed time designation information 410 for determining whether or not to delete the divided mail.

  When the split mail deletion enable / disable determination unit 252 with the RTC 14 determines whether or not the split mail can be deleted, the predetermined elapse time designation information 410 saved in the RAM 17 is used to determine whether or not the split mail can be deleted. A first predetermined elapsed time for determination, for example, X minutes, or a second predetermined elapsed time for determining whether or not a divided mail can be deleted is compared with the time measured by a timer when the RTC 14 is not provided, for example, X ′ Set as minutes.

  Thus, in this embodiment, the same effects as those in the above-described embodiments can be obtained, and further, the elapsed time corresponding to the designation from the divided mail transmission side is set to the divided mail. It can be used for determining whether or not deletion is possible, and it is possible to prevent the split mail receiving side from arbitrarily determining the first or second predetermined elapsed time for determining whether or not to delete split mail. Human troubles between sending and receiving emails related to email deletion can be avoided.

  Further, a second example of a different embodiment is that a divided mail abnormality notification mail to be transmitted to the transmission side or an electronic mail transmission / reception apparatus on the reception side when all of the partial mail elements constituting the divided mail are not prepared. This relates to the contents included in each of the divided mail abnormality notifications displayed on the display unit 13 of 1 and 1A.

  In the above-described embodiment, as shown in FIG. 8, the warning text 310, the transmission date and time 311, and the title 312 are included in the divided mail abnormality notification mail transmitted to the transmission side and the divided mail abnormality notification displayed on the screen on the reception side. In this embodiment, as shown in the table of FIG. 13, as shown in the table of FIG. 13, a mail that further includes the divided mail body 313 is transmitted as a divided mail abnormality notification mail. You may make it transmit to the side. FIG. 13 is a table showing another example of the mail format of the divided mail abnormality notification mail transmitted to the sender of the divided mail to be deleted. Similarly, a divided mail abnormality notification that further includes a divided mail body 313 may be displayed on the display unit 13 of the receiving side electronic mail transmitting / receiving apparatus 1 or 1A.

  Here, as the divided mail abnormality notification mail and the divided mail body 313 included in the divided mail abnormality notification, for example, even if the partial mail element is irregular, the first partial mail having a division number of “1”. If the element exists in the mailbox of the mail server, use an appropriate amount (partial or all) of the text information contained in the mail body (mail data) of the first partial mail element Anyway. In other words, the first partial mail element among the multiple partial mail elements constituting the divided mail is highly likely to contain the main body constituting the main part of the divided mail. It is likely that it will be easier to recognize what type of email was.

  Therefore, when the first partial mail element exists, the mail receiving application 25 of the e-mail transmitting / receiving apparatuses 1 and 1A receives the first first mail from the mail server prior to the deletion operation from the mail server. When downloading the mail data (mail body) of the partial mail element, temporarily saving it in the RAM 17, and creating the split mail abnormality notification mail to be transmitted to the transmission side or the split mail abnormality notification to be displayed on the reception side. , A warning sentence 310, a transmission date and time 311, a title 312, and an appropriate amount of text information (one data) included in the mail body (mail data) of the first partial mail element temporarily saved in the RAM 17. Part or all) may be added as the text 313.

  Thus, in the present embodiment, it is possible to determine the content of the deleted divided mail relatively easily by referring to the divided mail abnormality notification mail or the divided mail abnormality notification including the text 313. it can.

  In a third example of the different embodiment, the first predetermined elapsed time for determining whether or not to delete a divided mail, for example, X minutes or the second predetermined elapsed time, for example, X ′, is used as the transmission source address or transmission source of the divided mail. The value is set in advance according to the domain.

  In the first place, if any of the partial mail elements that make up the split mail do not reach the mail server (POP3) and become irregular, the split mail may be “a malicious attack” or “for mail delivery”. For example, the first predetermined elapsed time, for example, X minutes or the second predetermined elapsed time, for example, X ′ for determining whether or not to delete the divided mail depending on the transmission source domain. In the case of receiving mail within the intranet with high reliability, the first predetermined elapsed time for determining whether or not to delete the divided mail, for example, X minutes or the second predetermined elapsed time, for example, X ′ is used as much as possible. On the other hand, if it is received from the external Internet, the first predetermined elapsed time for determining whether or not the divided mail can be deleted, for example, X minutes or the second It may be set so that to extend the constant time elapsed for example X 'min. Alternatively, when registering a mail address of a mail transmission / reception destination in the address book of the electronic mail transmission / reception devices 1 and 1A, a first predetermined elapsed time for determining whether or not each divided mail can be deleted according to each mail address For example, the setting for X minutes or the second predetermined elapsed time, for example, X ′ may be distributed.

  Thus, the value designated in advance according to the destination domain and mail address is set to the first predetermined elapsed time for determining whether or not to delete the divided mail, for example, X minutes or the second predetermined elapsed time, for example, X ′ minutes. In the present embodiment to be set, it is possible to optimize the residence time in which mail remains in the mailbox of the mail server as much as possible, and to improve the memory efficiency of the mail server.

The configuration of the preferred embodiment of the present invention has been described above. However, it should be noted that such examples are merely illustrative of the invention and do not limit the invention in any way. Those skilled in the art will readily understand that various modifications and changes can be made according to a specific application without departing from the gist of the present invention.
For example, the embodiment of the present invention can be expressed as the following configuration in addition to the configuration (1) in the means for solving the problems.
(2) An e-mail transmission / reception apparatus that transmits / receives mail via a mail server, the mail for the e-mail transmission / reception apparatus stored in the mail server when receiving mail from the mail server The timer is started when it is detected that there is a divided mail divided into a plurality of partial mail elements and that all of the partial mail elements of the divided mail are not present in the mail server. Then, the timer waits until a predetermined second elapsed time elapses, and then, when the second predetermined elapsed time elapses, all of the partial mail elements of the divided mail are sent to the mail server. If it does not exist, the divided mail from the mail server is regarded as an irregular divided mail. Without performing the reception operation of Le, electronic mail transmission and reception apparatus for performing an instruction to delete the division mail from the mail server.
(3) If the first predetermined elapsed time or the second predetermined elapsed time is used, the source of the divided mail in which it is detected that all of the partial mail elements are not present in the mail server is the divided mail. The electronic mail transmitting / receiving apparatus according to (1) or (2), which is set to a time arbitrarily specified by a header portion of
(4) The first predetermined elapsed time or the second predetermined elapsed time, the mail address of the transmission source of the divided mail in which it is detected that all of the partial mail elements are not present in the mail server, or The electronic mail transmission / reception apparatus according to (1) or (2), wherein the electronic mail transmission / reception apparatus is set to a time designated in advance according to each domain of the divided mail transmission source.
(5) An e-mail receiving method in an e-mail transmitting / receiving apparatus for transmitting / receiving e-mail via a mail server, and the e-mail stored in the mail server when a mail receiving operation is performed from the mail server When it is detected that there is a divided mail divided into a plurality of partial mail elements as mail for the transmission / reception device, and all of the partial mail elements of the divided mail are not present in the mail server, The current time waits until the first predetermined elapsed time determined in advance from the transmission time of the divided mail, and then when the first predetermined elapsed time elapses, Check whether all the mails exist in the mail server. The without performing the division mail receiving operation from the mail server, e-mail receiving method for performing an instruction to delete the division mail from the mail server.
(6) An e-mail receiving method in an e-mail transmitting / receiving apparatus that transmits / receives e-mail via a mail server, and the e-mail stored in the e-mail server when receiving mail from the e-mail server When it is detected that there is a divided mail divided into a plurality of partial mail elements as mail for the transmission / reception apparatus, and that all of the partial mail elements of the divided mail are not present in the mail server , Start a timer, wait until the second predetermined elapsed time determined by the timer elapses, and then, when the second predetermined elapsed time elapses, all of the partial mail elements of the divided mail Is not present in the mail server, and if it does not exist, the mail is regarded as an irregular divided mail. Without performing the division mail receiving operation from Rusaba, e-mail receiving method for performing an instruction to delete the division mail from the mail server.
(7) When the first predetermined elapsed time or the second predetermined elapsed time is determined, the source of the divided mail in which it is detected that all of the partial mail elements are not present in the mail server is the divided mail The e-mail receiving method according to the above (5) or (6), which is set at a time arbitrarily designated by the header part of the above.
(8) The first predetermined elapsed time or the second predetermined elapsed time based on the email address of the transmission source of the divided emails detected that all of the partial email elements are not present in the email server, or The e-mail receiving method according to (5) or (6), wherein the e-mail receiving method is set to a time designated in advance according to each domain from which the divided mail is sent.
(9) An e-mail receiving program in which the e-mail receiving method according to any one of (5) to (8) is implemented as a program executable by a computer.
(10) A program recording medium in which the electronic mail receiving program of (9) is recorded on a computer-readable recording medium.

DESCRIPTION OF SYMBOLS 1 E-mail transmission / reception apparatus 1A E-mail transmission / reception apparatus 11 Main control part 12 Operation part 13 Display part 14 RTC
15 LAN controller 16 ROM
17 RAM
18 FLASH memory 21 LAN controller driver 22 TCP / IP protocol stack 23 POP3 client 24 SMTP client 25 Mail receiving application 26 Mail sending application 51 Header 52 Header 53 Header 54 Header 251 Split mail determination unit 252 Split mail deletion enable / disable determination unit 310 Warning text 311 Transmission date and time 312 Title 313 Text 410 Predetermined elapsed time designation information

Claims (8)

An e-mail transmission / reception device that transmits / receives mail via a mail server,
When a mail reception operation from the mail server is performed, there is a divided mail divided into a plurality of partial mail elements as a mail for the electronic mail transmitting / receiving device stored in the mail server, and When it is detected that all of the partial mail elements of the divided mail do not exist in the mail server, the current time waits until the first predetermined elapsed time determined in advance from the transmission time of the divided mail. After that, when the first predetermined elapsed time has passed, it is confirmed whether or not all the partial mail elements of the divided mail are present in the mail server. Does not receive the split mail from the mail server as an irregular split mail, and does not receive the split mail from the mail server. It is one that you want to delete,
The electronic mail transmitting / receiving apparatus according to claim 1, wherein the first predetermined elapsed time is set to a time arbitrarily specified by a transmission source of the divided mail by a header portion of the divided mail. An e-mail transmission / reception device that transmits / receives mail via a mail server,
When a mail reception operation from the mail server is performed, there is a divided mail divided into a plurality of partial mail elements as a mail for the electronic mail transmitting / receiving device stored in the mail server, and When it is detected that all of the partial mail elements of the divided mail are not present in the mail server, a timer is started, and the timer waits until a second predetermined elapsed time determined in advance has elapsed, Thereafter, when the second predetermined elapsed time has elapsed, it is confirmed whether all of the partial mail elements of the divided mail are present in the mail server. as irregular division mail, without the division mail receiving operation from the mail server, and deletes the partial email from the mail server There than,
The electronic mail transmitting / receiving apparatus according to claim 2, wherein the second predetermined elapsed time is set to a time arbitrarily specified by a transmission source of the divided mail by a header portion of the divided mail .   Based on the first predetermined elapsed time or the second predetermined elapsed time, it is detected that the partial mail elements are not present in the mail server. The e-mail transmitting / receiving apparatus according to claim 1, wherein the e-mail transmitting / receiving apparatus is set to a time designated in advance according to each of the transmission source domains. An e-mail receiving method in an e-mail transmission / reception apparatus for transmitting / receiving e-mails via a mail server, for the e-mail transmission / reception apparatus stored in the mail server when a mail reception operation is performed from the mail server If it is detected that there is a divided mail divided into a plurality of partial mail elements and that all of the partial mail elements of the divided mail are not present in the mail server, the current time is , Until the first predetermined elapsed time determined in advance from the transmission time of the divided mail, and then, when the first predetermined elapsed time has elapsed, all of the partial mail elements of the divided mail are Check if it exists in the mail server, and if it does not exist, Without performing the division mail receiving operation from the mail server, it is one that deletes the split mail from the mail server,
The e-mail receiving method according to claim 1, wherein the first predetermined elapsed time is set to a time arbitrarily specified by a sender of the divided mail by a header portion of the divided mail. An e-mail receiving method in an e-mail transmission / reception apparatus for transmitting / receiving e-mails via a mail server, for the e-mail transmission / reception apparatus stored in the mail server when a mail reception operation is performed from the mail server When it is detected that there is a divided mail divided into a plurality of partial mail elements, and that all of the partial mail elements of the divided mail are not present in the mail server, the timer is Start up and wait until the second predetermined elapsed time determined by the timer elapses, and then when the second predetermined elapsed time elapses, all of the partial mail elements of the divided mail are It is confirmed whether it exists in the mail server. If it does not exist, the mail Without performing the division mail receiving operation from server, from the mail server it is one that deletes the split mail,
The e-mail receiving method according to claim 2, wherein the second predetermined elapsed time is set to a time arbitrarily specified by a sender of the divided mail by a header portion of the divided mail . Based on the first predetermined elapsed time or the second predetermined elapsed time, it is detected that the partial mail elements are not present in the mail server. email receiving method according to claim 4 or 5, characterized in that to set the time that is specified in advance according to each sender domain. The email receiving method according to any one of claims 4 to 6, e-mail receiving program characterized by being implemented as a program executable by a computer. A program recording medium, wherein the electronic mail receiving program according to claim 7 is recorded on a computer-readable recording medium.

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