JP2000148609A - Mail system, mail client, mail server, and mail transmission and reception method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve security by preventing a user from referring to an account for registration previously stored by a mail client, and allowing the user to obtain a mail from a mail server through a network by using an account for connection different from the account for registration. SOLUTION: This system is constituted of an account-storing part 2d, in which a specific account for registration is stored so as to be prohibited from being referred to or rewritten by a user, a connecting part for executing connection with a mail server 4 by using the account for registration, a mail information controlling part for requesting connection via a network to the mail server 4 by using an account for connection and for obtaining and/or writing mail information, an account storing part 7a for storing the account for registration specific to a mail client 2, a certifying part 6b for certifying the account for registration stored in the account storing part 2d and the account storage part 7a, an issuing part 6c for issuing the account for connection, and a mail information storing part 7a for storing the mail information and the account for connection which corresponds to the account for registration.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method in which a user obtains mail from a server via a network by using a connection mail ID / password different from a registration mail ID / password stored in a terminal device in advance. Accordingly, the present invention relates to a mail system, a mail client, a mail server, and a mail sending / receiving method with improved security.

[0002]

2. Description of the Related Art Conventionally, fixed terminals such as personal computers (hereinafter, referred to as PCs) are often used as terminal devices (hereinafter, referred to as mail clients) in a mail system. A so-called registration account (hereinafter referred to as a registration mail ID, which is registration network information stored in the mail server in advance, so that the user can connect to the mail server using the mail client.
It is called a password. ) Must be obtained online or offline from the provider and registered each time the user connects to the mail server.

[0003]

When the mail client is a PC, the user needs to be familiar with the PC. Therefore, it is very difficult to immediately receive network services.

In addition, since the registration mail ID / password is stored in the mail client in advance, if the registration mail ID / password is used as it is, unless the rewriting work in the mail client can be easily performed, it is very difficult to secure. There is a problem of danger.

Therefore, the present invention prevents a user from referring to a registration account stored in a mail client in advance, and sends a mail from a mail server via a network using a connection account different from the registration account. It is an object of the present invention to provide a mail system, a mail client, a mail server, and a mail sending / receiving method with improved security by acquiring the mail system.

[0006]

In order to solve the above-mentioned problems, a mail system according to the present invention comprises: a mail server for storing mail information; and a mail server connected to the mail server via a network. In a mail system comprising a mail client for acquiring and / or writing, the mail client stores a unique registration account in a state where the user cannot refer to and rewrite the account, and the mail client account storage means; Connecting means for connecting to the mail server using a registration account, obtaining means for obtaining a connection account issued from the mail server, and using the connection account obtained by the obtaining means via the network Request connection to the above mail server and obtain the above mail information And / or writing mail information control means for a mail client, wherein the mail server includes a mail server account storage means for storing a registration account unique to the mail client, and a mail client account storage means. When there is a connection request from the mail client using the registration account stored in the storage unit, the registration account stored in the mail client account storage unit and the mail server account storage unit are stored. Authentication means for authenticating the registered account, issuing means for issuing the connection account, and mail information for storing the mail information in association with the registration account stored in the mail server account storage means Storage means and the connection account A connection account storage means for and storing association in the registration account stored in the account memory means for the mail server,
When a connection request is made from the mail client via the network using the connection account, a search is made for a registration account corresponding to the connection account stored in the connection account storage means, and the mail information storage is performed. And mail server mail information control means for providing and / or writing the mail information using the registration account stored in the mail server account storage means searched by the means.

In this mail system, by using a connection account associated with a unique registration account that the user cannot refer to or rewrite,
Get mail information from mail server via network.

Further, the mail client according to the present invention connects to a mail server that stores mail information received via a network and stores the mail information of the user, and obtains and / or obtains the mail information from the mail server. Alternatively, in a mail client to be written, a mail client account storage unit that stores a unique registration account in a state in which the user cannot refer to and rewrite the registration account, and a connection that connects to the mail server using the registration account. Means, acquisition means for acquiring a connection account issued from the mail server, and a connection request to the mail server via the network using the connection account acquired by the acquisition means, and the mail information Mail client mail to get and / or write Characterized in that it comprises an information control means.

In this mail client, mail information is obtained from a mail server via a network by using a connection account that is associated with a unique registration account that cannot be referenced and rewritten by a user.

The mail server according to the present invention stores mail information, and in a mail server for providing the mail information to a connected mail client, stores a registration account unique to the mail client. When there is a connection request from the mail client using the mail server account storage means and the registration account stored in the mail client account storage means, the mail client account storage means stores the connection request. An authentication unit for authenticating a registration account and a registration account stored in the mail server account storage unit; an issuance unit for issuing the connection account; and storing the mail information in the mail server account storage unit. Corresponds to the stored registration account Mail information storage means for storing and storing, the connection account storage means for storing the connection account in association with the registration account stored in the mail server account storage means, When a connection request is received from the mail client via a network, a search is made for a registration account corresponding to the connection account stored in the connection account storage means, and the mail searched by the mail information storage means A mail server mail information control means for providing and / or writing the mail information using the registration account stored in the server account storage means.

In this mail server, mail information is obtained from the mail server via a network by using a connection account associated with a unique registration account that the user cannot refer to and rewrite.

Further, the mail sending / receiving method according to the present invention provides a mail server comprising: a mail server that stores mail information; and a mail client that connects to the mail server via a network to obtain and / or write the mail information. In the transmission / reception method, the mail client stores a unique registration account in a state where it cannot be referenced and rewritten by a user. The mail server stores a registration account unique to the mail client. Then, the connection to the mail server is performed using the registration account. In the mail server, when there is a connection request from the mail client using the registration account stored in the mail client, the mail client The registration account stored by Authenticates the connection account and the registration account stored in the mail server, issues the connection account after this authentication, and obtains the connection account issued by the mail server in the mail client, and The server stores the mail information in association with the registration account stored in the mail server, and stores the connection account in association with the registration account stored in the mail server. The server searches for a registration account corresponding to the connection account stored in the mail server when the connection request is received from the mail client via the network using the connection account, and the server searches the registration account. The registered account stored in the above mail server There and providing and / or write the mail information.

In this mail sending / receiving method, mail information is obtained from a mail server via a network by using a connection account that is associated with a unique registration account that cannot be referenced and rewritten by a user.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

A mail system according to an embodiment to which the present invention is applied can be constructed using, for example, the Internet. First, a mail system according to a first embodiment of the present invention is shown in FIG.

The mail system 1 is, as shown in FIG.
For example, Personal Digital Assist
portable terminal 2 which is a tent (hereinafter, referred to as PDA)
, An access point 3, a mail server 4, a mail spool 5, an application server 6, a database 7, a gateway 8, and a personal computer (PC) 9.

The portable terminal 2 includes a wireless communication unit 2a having a function of communicating with a wireless communication network, a mail transmission / reception unit 2b for controlling transmission / reception of mail information via the network, and an application having functions such as a browser and a mailer. Part 2
c and the unique registration account are stored in a state where the user cannot refer to and rewrite the account (hereinafter, the unique registration account stored in such a state is referred to as the mobile terminal registration mail ID / password). .) Account storage unit 2d.

Here, the registration mail ID / password refers to registration network information stored in the mail server 4 in advance so that the user can connect to the mail server 4 using the portable terminal 2. . The portable terminal registration mail ID / password refers to a registration mail ID / password stored in advance in the portable terminal 2 which cannot be directly referenced and rewritten by the user himself / herself.

The access point 3 is a connection point at which a user can connect to the Internet.

The mail server 4 stores the mail client 2 in the user file 7a of the database 7 searched by the search unit 6d of the application server 6, which will be described later.
And a unique registration account (hereinafter, the unique registration account stored in such a state is referred to as a server registration mail ID / password). A mail server mail information control unit 4a for providing and / or writing is provided.

The mail server 4 has a computer
Transmis, a method of network communication
Sion Control Protocol / Int
A simple mail transfer protocol (SimpleMas) used for transferring e-mail in an Ethernet Protocol (hereinafter referred to as TCP / IP) network.
il Transfer Protocol) (hereafter, il Transfer Protocol)
It is called SMTP. ) Function and Post used for transfer of mail information from mail server to mail client
Office Protocol (hereinafter referred to as POP) function and Internet Message A
access protocol (hereinafter referred to as IMAP) function.

The mail spool 5 includes a mail storage unit 5a for storing received mail information.

The application server 6 includes an Internet mail receiving unit 6a for storing mail information received via the Internet, and a portable terminal when a connection request from the portable terminal 2 to the application server 6 via the access point 3 is received. An authentication unit 6b that authenticates whether the mobile terminal registration mail ID / password stored in 2 and the server registration mail ID / password stored in the database 7 are the same registration mail ID / password. A connection account (hereinafter referred to as a connection mail ID / password) from the database 7 later.
Mail ID / password issuing unit 6c for issuing
And the PC 9 using the connection mail ID and password.
And a search unit 6d that searches the database 7 for a server registration mail ID and password corresponding to the connection mail ID and password when the user requests connection to the application server 6 via the gateway 8.

Here, the connection mail ID / password is a PC using World Wide Web (WWW) mail client search and / or browsing software (WWW browser). ID and password used when connecting to the application server 6 via the Internet.

The connection mail ID and password are as follows:
The change may be made by the user using the mobile terminal 2.

The database 7 associates the connection mail ID / password with the server registration mail ID / password, and further associates the server registration mail ID / password with the mail information and stores the user file 7a or the like as a table. It has.

The database 7 also includes a user file 7a for storing user-specific information such as a user's birthday and telephone number as a table in association with the connection mail ID and password.

Here, the server registration mail ID / password cannot be directly referred to and / or rewritten by the user himself, but the person managing the application server 6 can refer to and / or rewrite as necessary. Refers to the registration mail ID and password.

More specifically, as shown in FIG. 2, the database 7 stores a connection mail ID / password and a server registration mail ID / password issued when there is a connection request from the portable terminal 2 to the mail server 4. A password is associated with the mail ID and password for registration, and the mail information stored in the mail spool 5 is stored in association with a so-called table.

That is, the database 7 stores a connection mail ID and password issued when a connection request is made from the portable terminal 2 to the mail server 4, that is, A (1),
A (2) ... A mail ID for connection that stores A (N)
A password storage unit 11, a server registration mail ID / password corresponding to each connection mail ID / password,
That is, a registration mail ID / password storage unit 12 for storing B (1), B (2)... B (N), and mail information corresponding to the registration mail ID / password, that is, C (1) ), C (2)... C (N).

Here, the case where the server registration mail ID / password and the mail information are set in one-to-one correspondence with each connection mail ID / password has been described. Good. That is, a plurality of server registration mail IDs / passwords and mail information may be set in one connection mail ID / password.

As shown in FIG. 3, the database 7 may store user-specific information as a table in association with the connection mail ID / password.

That is, the database 7 stores the connection mail ID / password storage section 11 described above and user-specific information corresponding to each connection mail ID / password, that is, D (1), D (2),. A user-specific information storage unit 15 for storing D (N), and a server registration mail ID / password corresponding to each set of a connection mail ID / password and user-specific information, that is, B (1) ,
B (2) ... E-mail ID for registration that stores B (N)
Password storage unit 12 and mail information corresponding to the registration mail ID and password, that is, C (1), C
(2)... Mail information storage unit 13 for storing C (N)
And may be composed of

Here, the case where the mail ID / password for server registration and the mail information are set one-to-one for each set of the mail ID / password for connection and the information unique to the user is shown. This may be one-to-many. That is, each set of the connection mail ID / password and the user-specific information includes a plurality of server registration mails I
D. Password and mail information may be set.

The gateway 8 is a device for converting a protocol so that mail information can be exchanged between different mail systems.

The PC 9 includes a device having the same function as the portable terminal 2 described above.

The mail system 1 configured as described above performs the following processing.

First, as a premise, a server system dedicated to the portable terminal 2 is constructed, and the server system manages the terminal device 2.

Next, in the first embodiment, a series of processes from when the portable terminal 2 or the PC 9 connects to the mail spool 5 via the application server 6 and when mail information is obtained from the mail spool 5 will be described. 4 is shown in FIG.

In step S1 of FIG.
Is powered on and the application server 6
When the user can communicate with the application server, the user operates the WWW application of the application unit 2c, and obtains a "connection mail ID and password for connecting to the application server via the Internet using a PC." Select the "Publish" application.

The portable terminal 2 transmits an application start request message to the application server 6 when an item necessary for issuing a connection mail ID and password is input by the user.

Here, the necessary items refer to user-specific information, such as the user's telephone number, for specifying the user by the application server 6.

In step S2, upon receiving the application activation request message, the application server 6 transmits a response message to the portable terminal 2.

In step S 3, the mobile terminal 2 transmits to the application server 6 the user previously stored in the mobile terminal 2, the mobile terminal registration mail ID / password and the connection mail ID / password issuance request message.

The application server 6 stores the mobile terminal registration mail ID / password and the connection mail ID / password.
When the password issuance request message is received, the e-mail ID / password for mobile terminal registration and the administrator of the application server 6 stored in the database 7 make the e-mail ID / password for server registration the same e-mail ID / password for registration. Authenticate whether it is a password.

In step S 4, after this authentication, the application server 6 searches the database 7 for a connection mail ID and password corresponding to the requested portable terminal 2 and issues it to the portable terminal 2. A password issuance process is performed, and the connection mail ID and password are transmitted to the mobile terminal 2.

The application server 6 registers the issued connection mail ID and password in the database 7.

The PC 9 acquires mail information from the mail spool 5 by using the connection mail ID and password received by the portable terminal 2 as described below.

Hereinafter, a case where the user connects to the application server 6 via the Internet will be described.

In step S5, the PC 9 transmits to the application server 6 a connection mail ID / password and a mail information acquisition request message requesting acquisition of mail information using the connection mail ID / password. .

In step S 6, the application server 6 determines that the administrator of the application server 6 corresponding to the received connection mail ID / password searches the database 7 for the server registration mail ID / password. A password search message is sent to the database 7.

In step S7, the database 7
Performs a registration mail ID / password search end process of transmitting the searched server registration mail ID / password to the application server 6 when this search is completed, and sends the server registration mail ID / password to the application server 6. Send.

The application server 6 stores the received server registration mail ID / password and the database 7
Is authenticated as to whether the server registration mail ID and password stored in the server are the same registration mail ID and password.

In step S8, if the authentication is successful, the application server 6 sends an authentication response message to the PC 9.

In step S9, the portable terminal 2
By performing the OP protocol processing or the like, the mail information stored in the mail spool 5 is obtained and / or written.

As described above, according to the mail system 1 of the first embodiment of the present invention, a connection request is issued from the terminal device other than the portable terminal 2 used in the mail system 1 to the access point 3 shown in FIG. Even the connection can be refused. Further, according to the mail system 1 according to the first embodiment of the present invention, the user cannot refer to and rewrite the registration mail ID / password registered in the mobile terminal 2 in advance, so that the security can be improved. The mail information can be obtained from the mail server 4 via the Internet in a state where the information has been improved.

Therefore, according to the mail system 1 according to the first embodiment of the present invention, the mail ID and password for connection adopted in the mail system 1 according to the first embodiment of the present invention are used. The connection through the access point 3 of the terminal device that is not used can be rejected.

In the first embodiment, a PC is used as a fixed terminal for acquiring mail information from the mail spool 5 via the Internet, but a terminal dedicated to the mail system 1 may be used in addition to the PC. Good.

The portable terminal 2 may be directly connected to a public network or the like without having a wireless function.

Further, the mail server 4 and the application server 6 may be configured as one server.

Finally, FIG. 5 shows a mail system according to a second embodiment of the present invention.

As shown in FIG. 5, the mail system 30 comprises a portable terminal 2, an access point 3, a mail server 4, a mail spool 5, an application server 6, a database 7, and a PC 9. I have.

That is, the mail system 30 is different from the mail system 1 in that the PC 9 is not connected to the application server 6 via the Internet but is connected to the application server 6 via a public network.

The mail system 30 having the above configuration is
The processing described below is performed.

First, similarly to the mail system 1 according to the first embodiment of the present invention, a server system dedicated to the portable terminal 2 is constructed as a premise, and the server system manages the terminal device 2.

Next, a series of processes from the connection of the portable terminal 2 or the PC 9 to the mail spool 5 via the application server 6 to the acquisition of mail information from the mail spool 5 will be described in a second embodiment. 6 is shown in FIG.

In step S11 of FIG. 6, when the power of the portable terminal 2 is turned on and communication with the application server 6 is possible, the user
By operating the WWW application of the application unit 2c, "an Internet connection ID / password for connecting to the Internet via a public network using a PC, and a connection mail ID for connecting to an application server via the public network"・ Issue with password "application.

The portable terminal 2 transmits an application start request message to the application server 6 by inputting the items required for issuing these IDs and passwords to itself.

Here, necessary items refer to user-specific information such as a user's telephone number.

In step S12, upon receiving the application activation request message, the application server 6 transmits a response message to the portable terminal 2.

In step S13, the portable terminal 2
A mobile terminal registration e-mail ID stored in advance
The password, the connection mail ID / password issuance request message, and the Internet connection ID / password issuance request message are transmitted to the application server 6.

The application server 6 stores the mobile terminal registration mail ID / password and the connection mail ID / password.
Upon receiving the password issue request message and the Internet connection ID / password issue request message,
The administrator of the application server 6 stored in the database 7 authenticates whether the mobile terminal registration mail ID / password and the server registration mail ID / password are the same registration mail ID / password.

In step S14, after this authentication, the application server 6
Connection ID / password issuance processing of retrieving the connection mail ID / password corresponding to the password from the database 7 and issuing it to the portable terminal 2, and an Internet connection ID for connecting to the Internet via a public network.
・ Password is retrieved from database 7 and portable terminal 2
Then, an Internet connection ID / password issuance process is issued to the mobile terminal 2 to transmit the connection mail ID / password and the Internet connection ID / password.

The application server 6 registers the issued connection mail ID and password in the database 7.

In step S 15, the PC 9 transmits the Internet connection ID and password issued via the access point 3 to the application server 6 to connect to the Internet.

The application server 6 performs connection authentication processing to determine whether the received Internet connection ID / password is a correct Internet connection ID / password.

In step S 16, if the connection authentication is successful, the application server 6 sends a connection authentication response message to the PC 9.

When the PC 9 connects to the Internet,
As described below, the mail information is acquired from the mail spool 5 by using the connection mail ID and password received by the mobile terminal 2.

Hereinafter, a case where the user connects to the application server 6 via the Internet will be described.

In step S17, the PC 9 connects the connection mail ID / password and the connection mail ID / password.
An e-mail information acquisition request message for requesting e-mail information acquisition using a password is transmitted to the application server 6.

In step S 18, the application server 6 determines that the administrator of the application server 6 corresponding to the received connection mail ID / password searches the database 7 for the server registration mail ID / password. A password search message is sent to the database 7.

At step S19, the database 7
Performs a registration mail ID / password search end process of transmitting the searched server registration mail ID / password to the application server 6 when this search is completed, and sends the server registration mail ID / password to the application server 6. Send.

The application server 6 stores the received server registration mail ID / password and the database 7
Is authenticated as to whether the server registration mail ID and password stored in the server are the same registration mail ID and password.

In step S20, if the authentication is successful, the application server 6 sends an authentication response message to the PC 9.

In step S21, the portable terminal 2
The mail information stored in the mail spool 5 is obtained and / or written by performing POP protocol processing and the like.

As described above, according to the mail system 30 of the second embodiment of the present invention, a connection request from the terminal device other than the portable terminal 2 used in the mail system 1 to the access point 3 shown in FIG. Even the connection can be refused. Further, according to the mail system 1 according to the first embodiment of the present invention, the user cannot refer to and rewrite the registration mail ID / password registered in the mobile terminal 2 in advance, so that the security can be improved. The mail information can be obtained from the mail server 4 via the Internet in a state where the information has been improved.

Therefore, according to the mail system 30 of the second embodiment of the present invention, the mail ID and password for connection adopted in the mail system 30 of the second embodiment of the present invention are used. The connection through the access point 3 of the terminal device that is not used can be rejected.

In the second embodiment, the PC is used as the fixed terminal for acquiring the mail information from the mail spool 5 via the public network.
A dedicated terminal or the like may be used.

Further, the portable terminal 2 may be directly connected to a public network or the like without having a wireless function.

Further, the mail server 4 and the application server 6 may be configured as one server.

[0091]

As described above, according to the mail system, the mail client, the mail server, and the mail sending / receiving method according to the present invention, a unique registration account that cannot be referenced and rewritten is not disclosed to the user. Since it is possible to obtain mail information from a mail server via the Internet, security performance can be improved. Therefore, the mail system according to the present invention,
According to the mail client, the mail server, and the mail sending / receiving method, the connection from the mail client can be rejected.

Further, according to the mail system, the mail client, the mail server and the mail sending / receiving method according to the present invention, when the user purchases the mail client, the mail information or the like can be immediately obtained without complicated settings. Can be.

[Brief description of the drawings]

FIG. 1 is a block diagram of a mail system according to a first embodiment of the present invention.

FIG. 2 is a diagram for explaining a table stored in a database showing a relationship between a connection mail ID / password, a server registration mail ID / password, and mail information.

FIG. 3 is a diagram for explaining a table stored in a database showing a relationship between a connection mail ID / password, user-specific information, a server registration mail ID / password, and mail information.

FIG. 4 is a process transition diagram showing a series of processes until mail information is acquired in the first embodiment of the present invention.

FIG. 5 is a block diagram of a mail system according to a second embodiment of the present invention.

FIG. 6 is a process transition diagram showing a series of processes until mail information is acquired in the second embodiment of the present invention.

[Explanation of symbols]

1 mail system, 2 mobile terminal, 3 access point, 4 mail server, 5 mail spool, 6 application server, 7 database, 8 gateway, 9 PC

Claims (9)

[Claims] 1. A mail server for storing mail information,
In a mail system comprising a mail client connected to the mail server via a network to acquire and / or write the mail information, the mail client cannot reference and rewrite a unique registration account by a user. Mail client account storage means stored in a state; connection means for connecting to the mail server using the registration account; acquisition means for acquiring a connection account issued from the mail server; Means for requesting a connection to the mail server via the network using the connection account obtained by the means, and obtaining and / or writing the mail information. Specific to the above mail client A mail server account storing means for storing a registration account; and a mail client using the registration account stored in the mail client account storing means, for receiving a connection request from the mail client. An authentication unit for authenticating the registration account stored in the account storage unit and the registration account stored in the mail server account storage unit; an issuing unit for issuing the connection account; A mail information storage unit that stores the mail server in association with the registration account stored in the mail server account storage unit; and a mail server that associates the connection account with the registration account stored in the mail server account storage unit. Connection account storage means for storing When a connection request is made from the mail client via the network using a connection account, a search is made for a registration account corresponding to the connection account stored in the connection account storage means, and the mail information storage means is searched. A mail server mail information control means for providing and / or writing the mail information by using the registration account stored in the mail server account storage means retrieved by the mail system. 2. When the mail client requests connection to the mail server using the registration account stored in the mail client account storage means, the mail client account storage means stores the request. After authenticating the registered account and the registered account stored in the mail server account storage unit, the connection account is issued,
2. The mail system according to claim 1, wherein the connection account is rewritten by a user. 3. The authentication means includes: a registration account stored in the mail client account storage means; a registration account stored in the mail server account storage means; and unique information of the mail client. 2. The mail system according to claim 1, wherein the e-mail system authenticates the following. 4. The mail system according to claim 1, wherein said mail information storage means stores network information, telephone information, and said mail information. 5. The mail server according to claim 1, further comprising an association storage unit configured to associate and store the registration account stored in the mail server account storage unit with the unique information of the mail client. The mail system according to claim 1, wherein 6. The mail server rejects issuing and / or rewriting of the connection account to the mail client in which the mail client account storage unit does not store a registration account. The mail system according to claim 1, wherein 7. A mail client which accumulates mail information received via a network and stores the mail information of a user and obtains and / or writes the mail information from the mail server. Mail client account storage means for storing the registration account of the user in a state in which it cannot be referenced and rewritten by the user, connection means for connecting to the mail server using the registration account, and issuance from the mail server Acquiring means for acquiring the connection account obtained, and a mail client for making a connection request to the mail server via the network using the connection account acquired by the acquisition means, and acquiring and / or writing the mail information. Mail information control means. That e-mail client. 8. A mail server for storing mail information and providing the mail information to a connected mail client, comprising: mail server account storage means for storing a registration account unique to the mail client; When there is a connection request from the mail client using the registration account stored in the mail client account storage means, the registration account stored in the mail client account storage means and the mail server Authentication means for authenticating the registration account stored in the account storage means, issuance means for issuing a connection account, and associating the mail information with the registration account stored in the mail server account storage means Mail information storage means for storing A connection account storage unit for storing the connection account in association with a registration account stored in the mail server account storage unit; and a connection request from the mail client via the network using the connection account. In this case, the registration account corresponding to the connection account stored in the connection account storage unit is searched, and the registration stored in the mail server account storage unit searched by the mail information storage unit is performed. A mail server for providing and / or writing the mail information by using a mail account. 9. A mail server for storing mail information,
In a mail sending and receiving method comprising a mail client connecting to the mail server via a network to acquire and / or write the mail information, the mail client cannot reference and rewrite a unique registration account by a user. The mail server stores a registration account unique to the mail client, the mail client uses the registration account to connect to the mail server, and the mail server stores the mail When a connection request is received from the mail client using the registration account stored in the client, the registration account stored in the mail client and the registration account stored in the mail server are authenticated. After this authentication, the connection A count is issued, the mail client obtains a connection account issued from the mail server, and the mail server stores the mail information in association with the registration account stored in the mail server. And storing the connection account in association with the registration account stored in the mail server, wherein the mail server uses the connection account and receives a connection request from the mail client via the network. Searching for a registration account corresponding to the connection account stored in the mail server, and providing and / or providing the mail information using the registration account stored in the mail server searched by the mail server. A mail sending and receiving method characterized by writing.