JP2000101634A - Mail delivery device and mail delivery method - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To solve the problem of garbled characters caused by RFC mismatch between a sending client and a receiving client. SOLUTION: Incoming mail and conversion conditions are retained for each mail account, and in response to a request from an arbitrary mail account, the conversion conditions and incoming mail of the mail account are read, and the incoming call is read in accordance with the conversion conditions of the mail account. The mail is converted and delivered to the mail account. If the conversion condition is set to, for example, convert the entire subject to half-width alphabet spelled in Roman when the subject of the mail includes two-byte characters, the subject can be prevented from being garbled on a client computer that does not support RFC1522.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mail delivery apparatus and a mail delivery method, and more particularly, to one of IP (Internet Protocol) protocols corresponding to a network layer of an OSI (Open System Interconnection) basic reference model. Is a mail delivery protocol (POP3 or IMA)
The present invention relates to a mail delivery device and a mail delivery method for delivering an electronic mail to a mail client using P4). POP3 is an abbreviation of Post Office Protocol ver.
MAP4 is Internet Massage Access Protocol ver.4
Is an abbreviation for

[0002]

2. Description of the Related Art The U.S. Department of Defense Advanced Research and Planning Agency (DARP)
A: Wide area packet communication network (ARPANET: Established by Defense Advanced Research Project Agency)
The purpose of the Advanced Research Project Agency Network) was not to centralize the computer in one place, but to decentralize the risk by decentralized management in various places, and the research was mainly for military use, Its great advantage (the ability to interconnect all computers on a network independent of computer architecture) spontaneously encourages the construction of a variety of non-military networks, which, as a matter of course, are interconnected. As a result, a large-scale global network called the "Internet" has emerged.

The first of useful technologies realized by the Internet is a seamless information browsing system using WWW (Word Wide Web), and the second is electronic mail (so-called Internet mail, generally E-mail). Internet mail is much more ubiquitous than traditional e-mail that depends on a specific network OS, and can be transmitted to any other party with a mail account. , Is one of the indispensable means of communication. As described above, there are two types of e-mail: Internet mail and conventional e-mail. Hereinafter, unless otherwise specified, e-mail and Internet mail are treated as synonyms.

As shown in FIG. 7, the electronic mail system includes a network 1 (strictly, a TCP / IP-based network; typically, the Internet), a mail transmission server (also referred to as an SMTP server) 2, and a mail reception server ( POP3 server) 3 and client computers 4 to 6 (three in the figure, but this number is an example), and comprises an SMTP server and a POP3 server.
The server function is software called MTA (Mail Transport Agent), and the mail client function is MU.
It is provided by software called A (Mail User Agent).

[0005] An outline of the flow from transmission to reception of an e-mail is as follows. An e-mail transmitted from a certain client computer 4 is a mail account of a sender, for example, a domain “bbb” corresponding to “aaa@bbb.co.jp”. .Co.jp ", is resent by the SMTP server 2 over the network 1, and after appropriate routing, finally, to the recipient's mail account, for example," sato @ casi ".
o. co. jp ", the domain" casio. c
o. jp "is delivered to the mailbox (Note 1) of the POP3 server 3.

Note 1: The mailbox is an account "sa" provided in a large-scale storage medium of the POP3 server 3.
to @ casio. co. jp "is a dedicated mail storage area, and corresponds to a post office box in general mail.

[0007] The received mail in the mailbox is stored in the account "sato@casio.co.j" of the mail.
The user having p "is downloaded from the mailbox to the client computer 5 (the client computer operated by the user) by the legitimate login to the POP3 server 3, and then deleted from the mailbox. Although it is possible to leave the information in the POP3 server 3 in the first place, in order to avoid pressure on the storage capacity of the POP3 server 3, the manner of using the e-mail is to always delete it.

FIG. 8 shows a client computer and a PO.
It is a timeline of a POP3 protocol exchanged between P3 servers. In this example, the account "sat
o @ casio. co. jp "is a domain" c "
asio. co. jp ", a series of steps from accessing the POP3 server, downloading the first electronic mail from its own mailbox, and deleting it is shown.

In FIG. 8, first, POP3 of the server
After establishing a session between the client computer and the POP3 server by connecting to a port (port 110 according to the definition of RFC1700) and establishing a session between the client computer and the POP3 server, "USER" of the POP3 protocol is used.
Sato "command and“ P ”of the POP3 protocol.
ASS abcde "command.
ER "and" PASS "are command names, and" sato "is" sato @ casio. co. jp "is the registered user name, and" abcde "is the registered password.

[0010] Next, the POP3 server performs authentication based on the user name and the password, and when the POP3 server evaluates that the account is valid, opens the mailbox of the account and determines the number of received mails and the total mail size. Investigate and notify the client computer of the information. The notification message shown in the figure is “+ OK sat
o's mailbox has 2 message
(S) (320 octets) ", meaning that two e-mails have arrived in the mailbox with the user name" sato "and the total size is 320
Octet (7 bits × 320 bytes) ”.

When the number of received mails of the notification message is one or more, the client computer
A "LIST" command of the P3 protocol is issued, and the head number (number 1) of the size list for each mail returned from the POP3 server in response to this command is set to the argument n.
And issues a "RETR n" command of the POP3 protocol. The POP3 server delivers a mail header and a message body (hereinafter, referred to as “mail entity”) of list number n in response to the “RETR n” command,
Upon receiving (downloading) the mail entity, the client computer receives the POP3 protocol “DE”.
An "LEn" command is issued to request deletion of the nth mail, and a "QUIT" command is issued to end the session.

FIG. 9 is a data list at the time of mail distribution including a specific example of the mail entity. In the list, L1
L25 indicates a line number, (S) indicates data transmitted from the client computer, and (C) indicates response data from the POP3 server. The mail header is from L12 to L14, followed by one blank line consisting of only a line feed code, followed by a message body (L16 to L20), and terminated by a dummy line (L21) consisting of only a period (.).

By the way, since the message body shown in the figure is composed of only half-width alphabets (single-byte characters), the meaning can be understood as it is. However, if the message body contains two-byte characters or binary data like Japanese. It becomes a list of unclear symbols and becomes unreadable. This was an unavoidable limitation due to the development environment of Internet mail (1-byte character environment in English-speaking countries). However, it is inconvenient in view of the nature of e-mail, which involves exchanging information with an unspecified number of users worldwide, across language boundaries. Therefore, according to the definition of RFC1468 in June 1998, two-byte If characters or binary data are included, use JIS Kanji code (iso-2022-j
p) was sent in 7 bits, and it was developed to decode (decode) it on the client side and play it back as before. That is, in RFC1468, the mail header includes a “Content-Type header” and a “Content
It has been decided to add a t-Transfer-Encoding header to specify a decoding method to be used on the receiving side.

For example, when a text document is sent using JIS kanji code (iso-2022-jp) of 7 bits, Content-Type: text / plain; charset = "ISO-2022-JP" Content-Transfer-Encoding: 7bit Or HTML (Hyper Text Markup Lang)
uage) format, add Content-Type: text / html; charset = "ISO-2022-JP" Content-Transfer-Encoding: 7bit. The difference between the two is “Content-Type
Header ". That is," text / plain "for a pure text document and" text / html "for an HTML format. In particular, when sent in the HTML format, the size and color of a character You can freely select fonts and font types, and you can send documents with good appearance and good design, so you can deliver mails that are far more expressive than pure text documents only. it can.

[0015] RFC1468 is a definition for two-byte characters in a message body, and does not take into account the subject (Subject header) of a mail header. For this reason, for the time being, the practice of "letting the subject not be written in Japanese and spelling it in English or Roman alphabets" continued, but today's RFC1522 was formulated because of its inconvenience. In this rule, JIS kanji code is used for the subject, for example, Subject: Thank you for today. Is: Subject: =? ISO-2022-JP? B? GyRCS1xGfCRPJCpIaCRsGyhK? = =? ISO-2022-JP? B? GyRCJDUkXiRHJDckPyEjGyhC? = Content-Type: text / plain; charset = "ISO-2022-JP" Content-Transfer -Encoding: Sended as a 7-bit code string, and this is now decoded on the receiving side.

[0016]

By the way, the above-mentioned RF
C (Request For Comments) is an Internet research and development institution, IETF (Internet Engineering Task
Force) is a group of documents (TCP / IP standard) that are indispensable for the development of technology related to the Internet, but their descriptions are not mandatory.

Therefore, MTA, MUA, and the like may not always conform to all RFCs depending on the development time and the development concept. Particularly, in the case of a client computer without a dedicated manager, The old version of the MUA may be used forever. For example, if a client computer with a MUA that does not support RFC1522 receives an email that contains 2-byte characters in the subject, the subject may be garbled. . MUs that do not support RFC1468
When a client computer having A receives a mail including a 2-byte character in the text, the text is garbled.

Further, as a code / encoding method of the attached file, RFC1341 / 13 in June 1992
42 (Note 2) is defined in this RFC1341.
When a mail with an attached file is received by a client computer that has an MUA that does not support / 1342, a part of the text (the part where the binary data of the attached file is converted into a readable character string and embedded) is garbled. There was a point.

Note 2: An agreement to convert binary data into readable characters using a predetermined encoding method, and to reproduce the original binary data using the same method. MIME (Mu
ltipurpose Internet Mail Extensions). The MIME method includes BASE64 for Windows (registered trademark), UENCODE for UNIX, and Ma.
BinHex for CINTOSH (registered trademark) and the like. RFCs 1341/1342 are subsequently
It was revised to 45-2049.

The above problem is, in short, an RFC of the MUA mounted on the client computer on the mail receiving side.
The point is that the application status (the type of mailer and its version) cannot be grasped on the mail sending side. For this reason, all RF
C-compliant mail, for example, mail containing 2-byte characters in the subject or body, mail with attached files, or HTM
Even if a mail in the L format or the RTF format is sent, there is a disadvantage that some or all of the mail cannot be read unless the receiving side supports all RFCs.

Therefore, the present invention provides an R
To solve the problem of garbled characters due to RFC mismatch between the sending client and the receiving client by registering the FC support status in the server, processing the incoming mail based on the registration information, and delivering it to the receiving client With the goal.

[0022]

According to a first aspect of the present invention, there is provided an e-mail delivery device, comprising: a first holding unit for holding incoming mail for each mail account; a second holding unit for holding conversion conditions for each mail account; A search means for searching for a conversion condition of the mail account in response to a request from the mail account, and reading an incoming mail of the mail account in response to a request from an arbitrary mail account; When the conversion condition of the account is found, a distribution means for converting the incoming mail in accordance with the conversion condition and delivering the converted mail to the mail account is provided. Claim 2
2. The mail delivery device according to claim 1, wherein one of the conversion conditions includes two characters in the subject of the mail.
When a byte character is included, the condition is a condition indicating that the entire subject is to be converted into Roman alphabet spelling of a half-width alphabet. According to a third aspect of the present invention, there is provided the mail delivery device according to the first aspect, wherein one of the conversion conditions is that the body of the mail is in an HTML format, a rich text format, or another format with format information. It is a condition indicating that the whole is converted into a text format. According to a fourth aspect of the present invention, there is provided the mail delivery device according to the first aspect, wherein one of the conversion conditions is a condition indicating that if the mail has an attached file, the attached file is deleted. Features.
According to a fifth aspect of the present invention, in the mail distribution apparatus according to the first aspect, when one of the conversion conditions includes an attached file in the mail, the attached file is deleted and the name of the attached file is changed. It is characterized by the condition indicating that it is inserted into the text. According to a sixth aspect of the present invention, in the mail distribution apparatus of the first aspect, the mail distribution apparatus further includes a WWW server that publishes an HTML document for setting the conversion condition on a network. The mail distribution method according to claim 7, wherein the first step of storing incoming mails for each mail account, the second step of storing conversion conditions for each mail account, and the step of responding to a request from any mail account. A third step of searching for a conversion condition of the mail account; reading out an incoming mail of the mail account in response to a request from an arbitrary mail account; and when the conversion condition of the mail account is searched in the third step Converting the incoming mail in accordance with the conversion condition and delivering the mail to the mail account. An eighth aspect of the present invention is a storage medium storing a program for realizing the first holding unit, the second holding unit, the search unit, and the distribution unit according to the first aspect.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings, taking a mail distribution system connected to the Internet as an example. In FIG. 1, reference numeral 10 denotes the Internet, 11 denotes a WWW server, 12 denotes a mail server (SMTP server and POP3 server) equipped with MTA, 13 denotes a database functioning as a second holding unit described in the gist of the invention, and 14 to 16 denote databases. These are first to third client computers each equipped with a MUA.
Needless to say, the number of client computers is an example.

FIG. 2 is a block diagram common to the WWW server 11 and the mail server 12. If described as a WWW server 11 for convenience, 11a is a CPU, 11b is a CP
RAM serving as working memory of U11a, 11c
Is an OS or WWW server program (SMTP / POP3 mail server program for mail server 12)
11d is a We in HTML format.
b public storage area containing the document (mail server 1
In the case of 2, a second storage unit having a mail box storing incoming mails for each mail account), a communication interface unit 11e for performing data communication with the Internet 10, and a bus 11f connecting each unit. The CPU 11a of the mail server 12 functions as a search unit and a distribution unit described in the gist of the invention, and the first storage unit 11c of the mail server 12 functions as the first holding unit.

Here, the MUAs mounted on the first and second client computers 14 and 15 correspond to all RFCs.
, But the third client computer 1
It is assumed that the MUA mounted on 6 supports only some RFCs. That is, the e-mail transmitted from the first client computer 14 (or the second client computer 15) is, for example, an e-mail including a 2-byte character in the subject or the body, and in some cases, an e-mail with an attached file. In some cases, the mail is in HTML format or RTF format in some cases, but the third client computer 16 has a problem that such a mail cannot be received as it is.

In the present embodiment, such a problem is solved by providing the following technical items. (1) Mail server 12: As described above, it is a server that also serves as an SMTP server and a POP3 server. The same domain as the mail server 12 (for example, “casio.c
o. jp "), the e-mail transmitted via the mail server 12 (the SMTP server) is sent to the mail server 1 when the destination POP3 server (destination domain is" casio.co.jp ").
2 POP3 server) and, for example, "s
ato @ casio. co. The e-mail addressed to “jp” is delivered to the mailbox of the mail server 12 (of the POP3 server).

(2) WWW server 11: WWW server 1
One basic function is to provide a WWW service for publishing an HTML document to a client computer connected to the Internet 10. There are two types of WWW services: static HTML document publication and so-called active HTML document publication whose contents dynamically change in response to client operations. The WWW server 11 of the present embodiment Provide the latter service (referred to as "dynamic service" for convenience).

FIG. 3 is a conceptual diagram of a dynamic service according to the present embodiment.
The URL of the WWW server 11 (Uniform Re
source location), the WWW server software 21 first transmits a predetermined root document (so-called homepage) to the WWW browser 20, and responds to a click on a link location appropriately set in the root document by For example, a “mail reception option setting page” as shown in FIG. 4 is transmitted.

In the mail receiving option setting page, H
Several input items designed in TML notation are provided. The items include, for example, a text box 31 for inputting a registrant's e-mail address (e-mail account), and double-byte characters (two-byte characters) in the subject. ), A check box 33 for allowing the body to be in HTML format, a check box 34 for allowing the body to be in rich text (RTF) format, and an option for allowing the attached file. A button 35, an option button 36 for disallowing the attached file, a check button 37 for permitting the insertion of the name of the attached file in the text, and the like.

The send button 38 at the bottom of the page is a so-called submit button (HTML notation: <INPUT TYPE
= "submit" VALU = "send">), and when this button is pressed, the input data of each of the above items is
1 to a CGI (Common Gateway Interface) 22. The stop button 39 at the bottom of the page is a so-called reset button (HTML notation: <INPUT TYPE = "reset" VALU = "stop">). Pressing this button clears the input data of each item described above. It is supposed to be.

The CGI 22 is a WWW server program 2
1 is a dedicated program for interfacing with the database 13 and the CGI 22 according to the present embodiment.
Receives transmission data from the WWW browser 20 (transmission data when the transmission button 38 is pressed) and stores it in a table of the database 13.

FIG. 5 is a conceptual diagram of a table in the database 13. This table is conveniently labeled "ADRE
Many records with six fields named "S", "Subject", "HTML", "RTF", "Attachment" and "File name" (one record is shown in the figure)
And the data stored in each field is as follows.

(A) ADRS field: The input data (mail address of the registrant) of the text box 31 is stored. (B) Subject field: The value of the check box 32 (True when inputting full-width characters in the subject is permitted, False when not permitting). (C) HTML field: The value of the check box 33 (True when the HTML format is permitted in the text, False when not permitted) is stored. (D) RTF field: the value of the check box 34 (True to permit the rich text format in the text)
e, False if not permitted) is stored. (E) Attached field: The value of the option group including the option buttons 35 and 36 (“0” when the attached file is permitted, “1” when the attached file is not permitted) is stored. (F) File name field: The value of the check button 37 (True when permitting insertion of the attached file name into the text, False when not permitted) is stored.

For example, in the input state of FIG.
Is pressed, the values shown in FIG. 5 are stored in the table of the database 13 (ADSRS=sato@casio.co.j).
p, Subject = True, HTML = True, RFT = T
(rue, attachment = 0, file name = False).

Next, the operation will be described. FIG. 6 is a flowchart showing the main part processing of the POP3 server program of the mail server 12. This flow chart first
USER command from client computer and P
Upon receiving an ASS command, an authentication process is performed (S1),
It is determined whether the registered e-mail account is valid (S2). If the authentication result is NG, the process is terminated. If the authentication result is OK, the fact is notified to the client computer, a LIST command from the client computer is accepted, the mailbox of the mail client is opened, and the total number of incoming mails is counted. Execute processing for notifying the client computer of the size (S
3).

Next, when there is an incoming mail (S4),
The table of the database 13 is searched, and the mail account (for example, “sato@casio.co.j”) is searched.
A record having an ADRS field in which data matching p ") is found, and data of all fields of the record are extracted (S5), and then the incoming mail is read from the mailbox (S6). It is determined whether or not there is a "conversion condition" of the mail based on the data extracted from the table (S7).

Here, the conversion condition is the RF applied to the MUA of the client computer on the mail receiving side.
The following conditions for matching C are referred to. (A) First conversion condition: a conversion condition that becomes “Yes” when the value of the subject field of the table is False (when double-byte characters are not permitted). If the first conversion condition is "Yes", the subject of the incoming mail is converted into Roman alphabet spelling of half-width alphabet (S8). (B) Second conversion condition: a conversion condition that becomes “Yes” when the value of the HTML field of the table is False (when the HTML format is not permitted). If the second conversion condition is "Yes", the body of the incoming mail is converted from HTML to text (S8). (C) Third conversion condition: a conversion condition that becomes “Yes” when the value of the RTF field of the table is False (when the rich text format is not permitted). If the third conversion condition is “Yes”, the body of the incoming mail is converted from rich text to text (S8). (D) Fourth conversion condition: a conversion condition that becomes “Yes” when the value of the attached field of the table is “1” (when the attached file is not permitted). If the fourth conversion condition is “Yes”, the code of the attached file is removed from the message body (S8). (E) Fifth conversion condition: a conversion condition that becomes “Yes” when the value of the file name field of the table is True (when the file name is inserted into the text). If the fifth conversion condition is "Yes", the file name of the attached file is inserted into an appropriate place in the mail text (S8).

Now, when all the conversion conditions are "none", that is, the subject field = True (allow double-byte characters) HTML field = True (permit HTML format) RTF field = True (permit rich text format) Yes) Attachment field = "0" (permits attachments) File name field = False (does not insert the file name in the body) If all the above conversion processes (S8) are passed, the PETR command and DE
After executing the processing of the LE command (S9, S10), the above processing is sequentially performed on the remaining incoming mail (S9).
11) When the remaining incoming mail is exhausted, the QUIT command from the client computer is processed (S1).
2) Then terminate the program.

Therefore, when all the conversion conditions are "absent", the incoming mail is kept almost intact (the changed part is only the route information added to the mail header by the mail server 12) and the receiving client computer is kept. However, if at least one of the conversion conditions is “Yes”, the conversion process (S8) according to the conversion condition is performed, and as a result, the incoming mail is not in its original form, but is received by the receiving client computer. It will be delivered after being converted to a form that conforms to RFC.

As described above, according to the present embodiment, the WWW server 11 is accessed from any client computer that can connect to the Internet, and FIG.
Open the "E-mail reception option setting page" in the WWW browser 20, enter required data in each item of the page, and press the send button 38 to set option settings relating to a specific e-mail account, that is, the subject of the received e-mail. Allow / Do not allow full-width characters in HTML Allow / or do not allow HTML format in text Allow / or do not allow rich text format in text Allow / or do not allow attached file Name of attached file in text Inserting / not inserting can be registered in the database 13. And
The mail server 12 requested to deliver the mail addressed to the mail account searches the database 13 to determine whether or not the option is set. If the option is set, the mail server 12 performs a required conversion process and then delivers the mail. The mail converted according to the above option setting is delivered to the client computer on the side.

Therefore, if the above option setting is adapted to the RFC of the MUA of the receiving client computer, for example, a client computer which does not support RFC1522 does not receive a mail including 2-byte characters in the subject, and Does not receive an email that contains 2-byte characters in the body of a client computer that does not support RFC1468,
Since a mail with an attached file is not received by a client computer that does not support 41/1342, a particularly advantageous effect is obtained in that the garbled problem caused by the RFC mismatch between the sending client and the receiving client can be reliably avoided.

Further, the main functions of the above embodiment (first holding means, second holding means, search means and distribution means)
Is a hardware asset, including a microcomputer,
Although it is functionally realized by organic combination with software assets such as an OS and various programs, general-purpose hardware assets can be used. Typically, O
It can be said that it is concentrated on S and various programs. Therefore, the present invention provides a floppy disk storing all or a main part of the OS and various programs,
It includes recording media such as MOs, CDs, hard disks, semiconductor memories, and the like (including those that are on a distribution channel itself, and those that are on a network and provide only recorded contents).

[0043]

According to the first to sixth and seventh aspects of the present invention, incoming mail and conversion conditions for each mail account are held, and the mail account is converted in response to a request from an arbitrary mail account. In addition to reading the conditions and the incoming mail, the incoming mail is converted according to the conversion conditions of the mail account and delivered to the mail account. Therefore, if the conversion conditions include, for example, 2-byte characters in the mail subject, Convert the entire subject to half-width Roman alphabet spelling, or convert the entire body to text when the body of the mail is in HTML, Rich Text, or other formats with formatting information, or If there is an attached file, delete the attached file, or If there is a setting to delete the attached file when there is a file and to insert the name of the attached file in the body, in the case of, it is possible to avoid garbled characters in the subject on the RFC1522 non-compliant client computer, In addition, in the case of (1) and (2), it is possible to avoid garbled characters in the body of the client computer that does not support RFC1341 / 1342, and in the case of (2), the receiving side can know what file is attached. Therefore, the RFC of the sending client and the receiving client
The problem of garbled characters due to the mismatch can be reliably avoided. According to the sixth aspect of the present invention, in the mail delivery device according to the first aspect, a WWW server for publishing the HTML document for setting the conversion condition on a network is included, so that the conversion can be performed regardless of location and time. You can set conditions.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a network configuration according to an embodiment;

FIG. 2 is a block diagram of a server (WWW server or mail server).

FIG. 3 is a schematic diagram of information transmission between a WWW browser and a database.

FIG. 4 is a display state diagram of a WWW setting screen according to the embodiment.

FIG. 5 is a table structure diagram of a database.

FIG. 6 is a flowchart at the time of mail distribution according to the embodiment;

FIG. 7 is a diagram of a conventional network configuration.

FIG. 8 is a timeline at the time of mail distribution.

FIG. 9 is a source list of an electronic mail including a mail header and a message body.

[Explanation of symbols]

 11a CPU (search means, distribution means) 11d second storage unit (first storage means) 13 database (second storage means)

Claims (8)

[Claims] A first holding unit for holding incoming mail for each mail account; a second holding unit for holding conversion conditions for each mail account; A search means for searching for a conversion condition; reading an incoming mail of the mail account in response to a request from an arbitrary mail account; if the search means finds the conversion condition of the mail account, And a delivery means for converting the incoming mail and delivering the mail to the mail account according to the following. 2. The method according to claim 1, wherein one of the conversion conditions is a condition indicating that the whole subject is converted into half-width alphabet spelled in Roman characters when the subject of the mail includes double-byte characters. The mail delivery device described. 3. One of the conversion conditions is a condition indicating that the entire text is converted to a text format when the text of the mail is in an HTML format, a rich text format, or another format information format. The mail delivery device according to claim 1, wherein: 4. The mail delivery device according to claim 1, wherein one of the conversion conditions is a condition indicating that, when the mail has an attached file, the attached file is deleted. 5. The method according to claim 1, wherein one of the conversion conditions is a condition indicating that, when there is an attached file in the mail, the attached file is deleted and the name of the attached file is inserted into the body. The mail delivery device according to claim 1, wherein 6. HTML for setting the conversion condition
2. The mail delivery device according to claim 1, further comprising a WWW server that publishes the document on a network. 7. A first step for storing incoming mail for each mail account, a second step for storing conversion conditions for each mail account, and a conversion condition for the mail account in response to a request from an arbitrary mail account. A third step of searching for an incoming mail of the mail account in response to a request from an arbitrary mail account, and if the conversion condition of the mail account is searched in the third step, A fourth step of converting the incoming mail in accordance with and delivering the mail to the mail account. 8. A storage medium storing a program for realizing the first holding means, the second holding means, the search means and the distribution means according to claim 1.