Patent Publication Number: US-2009228562-A1

Title: Mail sending and receiving apparatus, method, computer-readable medium and system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2008-012087, filed on Jan. 23, 2008, the entire contents of which are incorporated herein by reference. 
     FIELD 
     The present embodiment discussed herein is directed to mail sending and receiving programs, mail sending and receiving apparatuses, and mail sending and receiving systems for sending and receiving e-mails. 
     BACKGROUND 
     The present techniques relate to mail sending and receiving programs, mail sending and receiving apparatuses, and mail sending and receiving systems for sending and receiving e-mails. Particularly, the present techniques relate to a mail sending and receiving program, a mail sending and receiving apparatus, and a mail sending and receiving system with which it is possible to manage a mail account shared by a plurality of users. 
     With popularization of e-mails, state institutions, local governments, private companies, and other organizations have been using more and more e-mails for sending and receiving information to and from within and outside the organizations. 
     These organizations use mail addresses of the organization for contacting to the organization as a whole or mail addresses of subgroups of the organization (e.g., a department, a division, and a project team) for contacting to the subgroups (hereunder called representative addresses) in addition to personal mail address of persons in charge. 
     Regarding to this, a technique to transfer an e-mail directed to a representative address to registered multiple addresses as a broad cast mail are known (e.g., refer to Japanese Laid-open Patent Publication No. 2002-82876). This allows confirming and sharing the content of the e-mail received at the representative address throughout the subgroup. 
     There is a webmail software (hereunder, called “web mail” to read electronic mails on a browser software instead of on a mailer software. Using a webmail can ensure security, because all messages are managed by a server-side. 
     SUMMARY 
     An embodiment of the invention provides a method to facilitate sending and receiving e-mails, the method including: reading mail information from a mail-information memory regarding accessible e-mail accounts to which an authenticated user is permitted to have access; providing the mail information specific to a first one of the accessible email accounts; receiving a switching instruction to switch to a second one of the accessible email accounts; and automatically providing the mail information specific to the second one of the accessible email accounts upon accepting the switching instruction. The method may further include: accepting a reply instruction for creating a reply mail relative to an e-mail read at the second one of the accessible email accounts; and setting a reply address for the reply email to be the address associated with the second one of the accessible email accounts. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram showing an overview of an embodiment; 
         FIG. 2  is a diagram showing the system configuration according to the embodiment; 
         FIG. 3  is a diagram showing the hardware configuration of a mail server; 
         FIG. 4  is a block diagram showing functions of the mail server; 
         FIG. 5  is a diagram showing the data structure of an association table; 
         FIG. 6  is a diagram showing the data structure of a group table; 
         FIG. 7  is a diagram showing the data structure of an address table; 
         FIG. 8  is a diagram showing the data structure of a mail opening table; 
         FIG. 9  is a flowchart showing the procedure of a mailbox process; 
         FIG. 10  is a sequence diagram showing the procedure of a process for reading an e-mail in a mail system; 
         FIG. 11  is an illustration showing a log-in screen; 
         FIG. 12  is an illustration showing a post-log-in screen; 
         FIG. 13  is an illustration showing an account display screen for a personal address; 
         FIG. 14  is an illustration showing an account display screen for a representative address; and 
         FIG. 15  is an illustration showing a reply-mail creating screen. 
     
    
    
     DESCRIPTION OF EMBODIMENT 
     Now, an embodiment will be described with reference to the drawings. 
       FIG. 1  is a diagram showing an overview of the embodiment. A mail sending and receiving apparatus shown in  FIG. 1  sends and receives e-mails. Furthermore, the mail sending and receiving apparatus manages a plurality of mail accounts. A mail sending and receiving apparatus  1  is implemented by a computer functioning as described below according to a mail sending and receiving program. The mail sending and receiving apparatus  1  sends and receives e-mails and manages a plurality of mail accounts. The mail sending and receiving apparatus  1  includes switching-instruction accepting unit  1   a , mail-information providing unit  1   b , mail-information storage unit  1   c.    
     The switching-instruction accepting unit  1   a  accepts a switching instruction for switching an account for which mail information is provided by the mail-information providing unit  1   b  from one account to another. The switching instruction is issued by a user who reads e-mails in order to switch e-mails displayed on a display screen  3 . 
     The mail-information providing unit  1   b  reads mail information from the mail-information storage unit  1   c , and provides the mail information that has been read for each of account for management of e-mails. On the basis of the mail information provided by the mail-information providing unit  1   b , the content of e-mails and other information of an account that the user wishes to use for reading are displayed on a display screen on which the user can read e-mails. 
     The mail-information providing unit  1   b  switches the account for which mail information is read from the mail-information storage unit  1   c  and is provided from one account to another account according to the switching instruction accepted by the switching-instruction accepting unit  1   a . Accordingly, the mail information provided by the mail-information providing unit  1   b  is switched from that of the one account to that of the other account according to the switching instruction. Thus, it is possible to switch the content displayed on the display screen  3  according to the switching instruction by the user, for example, between a mail account screen A showing e-mails sent to a personal mail account and a mail account screen B showing e-mails sent to a representative mail account. 
     The mail-information storage unit  1   c  stores mail information relating to e-mails. The mail information includes a body, a source address, a destination address, a date and time of sending, and so forth for each e-mail. The content and other information of e-mails are displayed on the display screen  3  on the basis of the mail information. 
     With the mail sending and receiving apparatus  1  described above, the mail-information storage unit  1   c  stores mail information. The mail-information providing unit  1   b  reads mail information and provides the mail information that has been read for each account. The switching-instruction accepting unit  1   a  accepts a switching instruction. According to the switching instruction, the mail-information providing unit  1   b  switches the account of mail information to another account. 
     Accordingly, it is possible to switch an e-mail account for which mail information is provided by the mail server  100  among a plurality of accounts according to a switching instruction by the user. This facilitates reading and other management operations involving e-mails at a plurality of mail accounts by the user. 
     Now, the embodiment will be described in detail with reference to the drawings. 
       FIG. 2  is a diagram showing the system configuration of the embodiment. A mail system shown in  FIG. 2  is a system for sending and receiving e-mails within an organization  30  and between the inside of the organization  30  and the outside (terminal apparatuses  21 ,  22 ,  23 , . . . ) of the organization  30 . 
     The scope of an organization is defined as appropriate. In the case of a company, for example, a department may be considered as an organization, or the entire company may be considered as an organization. Similarly, in the case of a local government, for example, a section may be considered as an organization, or the entire government may be considered as an organization. 
     In the mail system according to this embodiment, terminal apparatuses  31 ,  32 , . . . are connected via a local area network (LAN)  10  to a mail server  100  for sending and receiving e-mails. Furthermore, the mail server  100  is connected to external terminal apparatuses  21 ,  22 ,  23 , . . . via the Internet  20 . 
     The mail server  100  sends and receives e-mails within the organization  30  and between the inside and outside of the organization  30 . Furthermore, the mail server  100  manages e-mail accounts within the organization  30 . 
     The mail server  100  has a function of storing internal mails created by users inside the organization  30  by using browsers on the terminal apparatuses  31 ,  32 , . . . . Furthermore, the mail server  100  has a function of receiving e-mails sent from the outside to the inside of the organization  30  via the Internet  20  and storing the e-mails. These functions are implemented by a mail-opening-information storage unit  140 , which will be described later. 
     Furthermore, the mail server  100  has a function of allowing users as recipients of e-mails, stored in the mail-opening-information storage unit  140 , to perform operations on the e-mails as Web mails in accordance with requests from the users by using browsers on terminal apparatuses  31 ,  32 , . . . . When a user wishes to read e-mails, the user is requested to enter a user ID and a password from a browser on one of the terminal apparatuses  31 ,  32 , . . . , and the user is allowed to read internal mails written to the user from the inside of the organization  30  and external mails sent to the user from the outside of the organization  30  only when the user ID and password match authentication information registered in advance. On occasion of reading e-mails, the mail server  100  sends via the LAN  10  information representing the content of e-mails relevant to the user&#39;s reading request to the browser of one of the terminal apparatuses  31 ,  32 , . . . (e.g., the terminal apparatus  31 ) that the user is operating. Upon receiving the information representing the content of the e-mail, the terminal apparatus  31  displays the content of the e-mails on the browser of the terminal apparatus  31 . 
     Furthermore, the mail server  100  has a function of sending e-mails created by using the browsers of the terminal apparatuses  31 ,  32 , . . . to the outside via the Internet  20 . On occasion of sending of an e-mail, the mail server  100  accepts a user&#39;s request for creating and sending an e-mail according to the Hypertext Transfer Protocol (HTTP), and sends the e-mail to a destination (e.g., a user of the terminal apparatus  21 ) specified by the user according to the Simple Mail Transfer Protocol (SMTP), the Post Office Protocol (POP)/Internet Message Access Protocol (IMAP). 
     In this embodiment, e-mails that are stored under management by the mail server  100  and that can be operated on browsers by users within the organization  30  only from the terminal apparatuses  31 ,  32 , . . . within the organization  30  are referred to as “Web mails”. Within the organization  30 , the users can read external mails sent from the outside of the organization  30  to the mail server  100  as well as internal mails as Web mails. 
     Furthermore, the users belonging to the organization  30  may be allowed to read e-mails on the mail system by connecting to the mail server  100  from external terminal apparatuses (not shown) outside the organization  30  via the Internet  20 . Also in this case, similarly to the case of using the terminal apparatuses  31 ,  32 , . . . inside the organization  30 , the users belonging to the organization  30  undergo authentication for log in based on user IDs and passwords by using terminals located outside the organization  30  and connected to the Internet  20 . Thus, the users belonging to the organization  30  can read e-mails received at a representative address even when the users are outside the organization  30 . 
     E-mails that are created at the terminal apparatuses  31 ,  32 , . . . inside the organization  30  and exchanged among the users inside the organization  30  are referred to as “internal mails”. On the other hand, e-mails exchanged between users inside the organization  30  and the outside of the organization  30  via the Internet  20  and the mail server  100  are referred to as “external mails”. 
     In this embodiment, “e-mails” include both internal mails and external mails, and also include Web mails. 
     That is, an internal mail is created on the browser at one of the terminal apparatuses  31 ,  32 , . . . inside the organization  30 . The internal mail that has been created is stored in the mail server  100  as a Web mail, and only a user who has logged in by using an account within the organization  30  set as a destination of the internal mail is allowed to read the Web mail. 
     When an external mail is sent from the inside to the outside of the organization  30 , a user creates the external mail by using the browser at one of the terminal apparatuses  31 ,  32 , . . . , and in response to a sending instruction by the user, the external mail is sent temporarily from the mail server  100  via the Internet  20  to a mail server (not shown) that manages e-mails of a user at the destination. Then, for example, the external mail is sent from the mail server that manages e-mails of the user at the destination to one of the external terminal apparatuses  21 ,  22 ,  23 , . . . used by the user at the destination. 
     As an example, description will be given in the context of a case where a user of the terminal apparatus  31  sends an external mail to a user of the external terminal apparatus  21  by using a mail address corresponding to a mail account managed by the mail server  100 . In this case, according to a user&#39;s operation performed by using the browser at the terminal apparatus  31 , upon creation of an e-mail addressed to the user of the terminal apparatus  21 , the terminal apparatus  31  sends a body of the e-mail and a mail address of the user of the terminal apparatus  21  at the destination to the mail server  100  via the LAN  10 . Upon receiving the mail address of the user of the terminal apparatus  21  at the destination and the mail body from the terminal apparatus  31 , the mail server  100  sends the e-mail created by the user of the terminal apparatus  31  and including the mail body to the destination mail address. 
     On the other hand, when an external mail sent from the outside of the organization  30  via the Internet  20  is received by the mail server  100 , similarly to the case of an internal mail, the external mail is stored at the mail server  100  as a Web mail, and only a user who has logged in by using an account within the organization  30  set as a destination of the external mail is allowed to read the Web mail on the browser at one of the terminal apparatuses  31 ,  32 , . . . inside the organization  30 . 
     As described above, the mail server  100  sends information of documents created by users within the organization  30  by using the terminal apparatuses  31 ,  32 , . . . as external mails to the outside of the organization  30 , and provides Web mails so that the users within the organization  30  can read e-mails by using the browsers running on the terminal apparatuses  31 ,  32 , . . . and so that other users within the organization  30  can perform operations involving the e-mails created. As described above, the mail server  100  according to this embodiment sends and receives e-mails to and from the inside and outside of the organization  30 , and manages received e-mails. With the mail server  100  according to this embodiment, it is possible to send an e-mail to addresses including destinations both inside and outside the organization  30 . 
     Furthermore, in this embodiment, external mails received from the outside of the organization  30  and internal mails are managed at the mail server  100  simply on the basis of source addresses without particular distinction between the external mails and the internal mails, and both the external mails and the internal mails are displayed simultaneously on occasion of a user&#39;s operation at one of the terminal apparatuses  31 ,  32 , . . . . Alternatively, however, as needed, external mails and internal mails may be managed distinctly, and may also be displayed distinctly. Yet alternatively, the mail server  100  may be configured to deal with only external mails or only internal mails. 
     Furthermore, although the mail server  100  has the function of managing Web mails in this embodiment, without limitation to the embodiment, an independent apparatus different from the mail server  100 , such as a server dedicated for Web mails, may have a function of managing Web mails, or an apparatus having another function, such as a server, may also have a function of managing Web mails. 
     The terminal apparatuses  21 ,  22 ,  23 , . . . are computers provided outside the organization  30  so that users outside the organization  30  can send e-mails, receive e-mails, and perform other operations involving e-mails. Each of the terminal apparatuses  21 ,  22 ,  23 , . . . has a function of sending and receiving e-mails. 
     The terminal apparatuses  31 ,  32 , . . . are computers provided inside the organization  30  so that users inside the organization  30  can use Web mails provided by the mail server  100 . Each of the terminal apparatuses  31 ,  32 , . . . has a function of using Web mails provided by the mail server  100 , and a function of operating the mail server  100  to send e-mails to and receive e-mails from the outside of the organization  30  via the Internet  20 . 
     Next, the hardware configuration of the mail server  100  will be described. 
       FIG. 3  is a diagram showing the hardware configuration of the mail server  100 . The mail server  100  as a whole is controlled by a central processing unit (CPU)  101 . The CPU  101  is connected to a random access memory (RAM)  102 , a hard disk drive (HDD)  103 , a graphic processor  104 , an input interface  105 , and a communication interface  106 . 
     The RAM  102  temporarily stores at least part of an operating system (OS) program and application programs executed by the CPU  101 . Furthermore, the RAM  102  stores various types of data needed for processing by the CPU  101 . The HDD  103  stores the OS and application programs. 
     The graphic processor  104  is connected to a monitor  11 . The graphic processor  104  displays images on a screen of the monitor  11  according to instructions from the CPU  101 . The input interface  105  is connected to a keyboard  12  and a mouse  13 . The input interface  105  sends signals sent from the keyboard  12  or the mouse  13  to the CPU  101  via a bus  107 . 
     The communication interface  106  is connected to networks such as the LAN  10  and the Internet  20 . The communication interface  106  sends data to and receives data from other computers via these networks. 
     The processing functions according to this embodiment can be implemented by the hardware configuration described above. 
     Next, the module configuration of the mail server  100  will be described. 
       FIG. 4  is a block diagram showing the functions of a mail server. 
     The mail server  100  sends and receives e-mails, and manages a plurality of accounts. For the purpose of management of a plurality of accounts, the mail server  100  includes a switching-request accepting unit  111 , a mail-information providing unit  112 , an authentication unit  113 , an account determining unit  114 , a reply-instruction accepting unit  115 , a source-address setting unit  116 , a mail-information storage unit  130 , a mail-opening-information storage unit  140 , and an account-information storage unit  150 . 
     Furthermore, the mail server  100  is connected via the LAN  10  to the terminal apparatus  31 , at which a user reads e-mails, and is connected via the Internet  20  to external terminal apparatuses  21 ,  22 ,  23 , . . . (see  FIG. 2 ). 
     The switching-instruction accepting unit  111  accepts a switching instruction for switching an account for which mail information is provided by the mail-information providing unit  112  from one account to another account. The switching instruction is input by the user performing operation on the browser at the terminal apparatus  31 . The switching instruction input to the terminal apparatus  31  is sent from the terminal apparatus  31  to the mail server  100  via the LAN  10 . When the user inputs the switching instruction, the user specifies an account for switching. The operation for switching will be described later in detail with reference to  FIGS. 13 and 14 . 
     The mail-information providing unit  112  reads mail information from the mail-information storage unit  130 . Furthermore, for each account for management of e-mails, the mail-information providing unit  112  provides the mail information that has been read via the LAN  10  to the terminal apparatus  31  where the user reads e-mails. 
     According to the switching instruction accepted by the switching-instruction accepting unit  111 , the mail-information providing unit  112  switching the account for which mail information is read from the mail-information storage unit  130  and is provided to another account specified in the switching instruction. 
     The mail-information providing unit  112  provides the terminal apparatus  31  via the LAN  10  with unopened mail information and opened mail information indicating whether any unopened mail exists in the accounts other than the account for which mail information is provided by the mail-information providing unit  112 . 
     At this time, the mail-information providing unit  112  first reads mail opening information from the mail-opening-information storage unit  140 . Then, the mail-information providing unit  112  generates unopened mail information and opened mail information with reference to the mail opening information read from the mail-opening-information storage unit  140  to indicate whether any unopened mail exists in the accounts determined by the account determining unit  114 . Then, the mail-information providing unit  112  provides the unopened mail information and opened mail information generated. 
     On the basis of the unopened mail information and opened mail information, information indicating whether any unopened mail exists is displayed on the browser of the terminal apparatus  31 . The display of information regarding unopened mails and opened mails will be described later in detail with reference to  FIGS. 12 to 14 . 
     The authentication unit  113  performs authentication of a user on the basis of an account ID such as a user ID and a password associated with the account ID input to the terminal apparatus  31 . Upon successful authentication, the mail server  100  permits log in by the user using the terminal apparatus  31 , and provides mail information on the basis of the account corresponding to the account ID used for authentication. Thus, the user can read, by using the terminal apparatus  31 , e-mails sent to the account corresponding to the account ID. 
     The account determining unit  114  reads account information from the account-information storage unit  150 , and with reference to the account information, determines accounts at which the user authenticated by the authentication unit  113  is allowed to read e-mails. 
     The reply-instruction accepting unit  115  accepts from the terminal apparatus  31  an instruction for creating a reply mail to an e-mail read at an account for which mail information is provided by the mail-information providing unit  112 . 
     The source-address setting unit  116  sets the mail address of the account at the source of the reply instruction for the e-mail as a source address of the reply mail based on the reply instruction accepted by the reply-instruction accepting unit  115 . The display on the browser of the terminal apparatus  31  and user&#39;s operation for setting the source address will be described later in detail with reference to  FIG. 15 . 
     The mail-information storage unit  130  stores mail information relating to e-mails. The mail information includes mail bodies and header information of internal mails created on the browsers of terminal apparatuses inside the organization  30  via the LAN  10 , such as the terminal apparatus  31 , and external mails sent from the outside of the organization  30  via the Internet  20  connected to the mail server  100 . The header information includes information indicating a source address, a destination address, a date and time of sending, and so forth. 
     The account-information storage unit  150  stores account information identifying accounts at which users are allowed to read e-mails. The account information storage unit  150  includes an association-information storage unit  151 , a group-information storage unit  152 , and an address-information storage unit  153 . The association-information storage unit  151  stores an association table  151   a  (see  FIG. 5 ). The group-information storage unit  152  stores a group table  152   a  (see  FIG. 6 ). The address-information storage unit  153  stores an address table  153   a  (see  FIG. 7 ). 
     The mail-opening-information storage unit  140  stores mail opening information indicating whether each e-mail has been opened at the log-in account. The mail-opening-information storage unit  140  stores a mail opening table  140   a  (see  FIG. 8 ). 
     The terminal apparatus  31  is connected to the mail server  100  via the LAN  10 . The terminal apparatus  31  displays information relating to e-mails based on mail information provided from the mail server  100  according to user&#39;s operations. Furthermore, the terminal apparatus  31  outputs a switching instruction to the mail server  100  according to a user&#39;s operation. 
     In this embodiment, the mail server  100  has the functions described above. Without limitation to the embodiment, however, an independent apparatus different from the mail server  100 , such as a dedicated server, may have all the functions described above. Yet alternatively, each of a plurality of apparatuses including the mail server  100  may have part of the functions described above so that the plurality of apparatuses as a whole has the functions described above. 
     Next, an association table used in the mail server  100  according to this embodiment will be described. 
       FIG. 5  is a diagram showing the data structure of an association table. The association table  151   a  shown in  FIG. 5  is created and managed by the mail server  100 . The association table  151   a  stores association information indicating corresponding relationship between individual users belonging to the organization  30  and individual groups of the organization  30 . 
     The association table  151   a  includes “user ID” indicating an identifier (ID) assigned to each user in the organization  30 , “user name” indicating a name of the user, “group ID” indicating an ID assigned to a group to which the user belongs, and “status” indicating the validity of the user ID. The items of information in each row are associated with each other to constitute association information. Although not shown in  FIG. 5 , the association information also includes a password used for authentication of the user in combination with the user ID. 
     The user ID is a code assigned to each user for identification of the user in the mail system, such as the mail server  100 . Thus, an arbitrary text string can be used as the user ID as long as the user ID allows unique identification of the user. The user name is a name of a user who belongs to the organization  30  and who uses the mail system. 
     The group ID is a code assigned to each group for identification of the group in the mail system. Thus, similarly to the user ID, an arbitrary code can be used as the group ID as long as the group ID allows unique identification of the group. 
     The status indicates the validity of the user ID. A “valid” status indicates that the user ID is usable. On the other hand, an “invalid” status indicates that the use of the user ID has been invalidated. 
     Each user can belong to one or more groups. In this embodiment, when a user belongs to a plurality of groups, a plurality of pieces of association information is created for the user, for example, as shown in the first and second rows from the top of the association table  151   a  shown in  FIG. 5 , so that the same user ID is associated with different group IDs individually in the pieces of association information. 
     Next, a group table used by the mail server  100  according to this embodiment will be described. 
       FIG. 6  is a diagram showing the data structure of a group table. The group table  152   a  shown in  FIG. 6  is created and managed by the mail server  100 . The group table  152   a  stores group information indicating information regarding each group of the organization  30 . 
     The group table  152   a  includes “group ID” indicating an ID of each group of the organization  30 , “group name” indicating a name of the group, “representative account ID” indicating a representative account ID for identifying a mail address assigned to the group, and “status” indicating the validity of the group ID. The items of information in each row are associated with each other to constitute group information. 
     As described earlier, the group ID is a code assigned to each group for identification of the group in the mail system. The group name is a name of each group of the organization  30  that uses the mail system. 
     The representative account ID is a code assigned to each group in order to associate the group with a representative address assigned to the group. Thus, similarly to the group ID, an arbitrary text string can be used as the representative account ID as long as the representative account ID allows unique identification of the group. 
     The status indicates the validity of the group ID. A “valid” status indicates that the group ID is usable. On the other hand, an “invalid” status indicates that the use of the group ID has been invalidated. 
     Next, an address table used by the mail server  100  according to this embodiment will be described. 
       FIG. 7  is a diagram showing the structure of an address table. The address table  153   a  shown in  FIG. 7  is created and managed by the mail server  100 . The address table  153   a  stores address information indicating address information of each user and each group of the organization  30 . 
     The address table  153   a  includes “account ID” indicating a user ID of a user having a mail address or a group ID of a group having a mail address, “name” indicating a name of the user or group, and “address” indicating the mail address assigned to the user or group. The items of information in each row are associated with each other to constitute address information. 
     The account ID is a code assigned to each user and each group in order to associate each user with a mail address assigned to the user and each group with a representative mail address assigned to the group in the address table  153   a . The name is a name of the user or group. The address is the mail address assigned to the user or the representative mail address assigned to the group. 
     In this embodiment, each group can have one representative address. Without limitation, however, each group may have two or more representative addresses assigned thereto. In this case, a plurality of pieces of address information is created for the same group, so that the same account ID (representative address ID) is associated with different representative mail addresses in the individual pieces of address information. 
     E-mails received at personal addresses and e-mails received at representative addresses are managed and stored in the mail-information storage unit on an account-by-account basis. When a user issues a request for reading e-mails from one of the terminal apparatuses  31 ,  32 , . . . that the user uses to the mail server  100 , on the basis of the association information, group information, and address information shown in  FIGS. 5 to 7 , for each account at which the user is allowed to read e-mails, mail information is provided to the terminal apparatus that the user uses, and mail bodies, the presence or absence of unopened mails, the number of unopened mails, and so forth are displayed on the browser on an account-by-account basis (see  FIGS. 12 to 15 ). 
       FIG. 8  is a diagram showing the data structure of a mail opening table. The mail opening table  140   a  shown in  FIG. 8  is created and managed by the mail server  100 . The mail opening table  140   a  stores mail opening information indicating whether each e-mail received by the mail server  100  has been opened by each user, and a date and time of opening by each user. As described earlier, e-mails include both internal mails and external mails. 
     The mail opening table  140   a  includes “mail number” indicating a number uniquely assigned to each e-mail for identification of the e-mail, “user ID” indicating a user who opened the e-mail, and “date and time of opening” indicating whether the e-mail identified by the mail number has been opened at the account corresponding to the user ID and a date and time of opening. The items of information in each row are associated with each other to constitute mail opening information. 
     The mail number is a number uniquely assigned to each e-mail received by the mail server  100  for the purpose of identification of the e-mail by the mail server  100 . The mail number of an external mail is assigned at the time of reception of the external mail by the mail server  100  via the Internet  20 . The mail number of an internal mail is assigned at the time of storage at the mail server  100  of the internal mail sent via the LAN  10  to the mail server  100  after the internal mail is created at one of the terminal apparatuses  31 ,  32 , . . . . 
     The user ID indicates a user who is opened the e-mail identified by the mail number. More specifically, a mail address to which the e-mail identified by the mail number is addressed is obtained, and a user corresponding to the mail address is recorded. The date and time of opening indicates whether the e-mail identified by the mail number has been opened by the user identified by the user ID, and a date and time of opening by the user. 
     Each time an external mail sent from the outside of the organization  30  is received and each time an internal mail is created inside the organization  30 , the mail server  100  creates mail opening information as shown on each row of the mail opening table  140   a . Since the e-mail is not yet opened at this time, “not yet opened” is set as the date and time of opening. 
     The mail opening information is created individually for each e-mail opened and for each account corresponding to a destination of the e-mail. That is, if an e-mail has a plurality of destination addresses, the mail opening information is created for each user to which the e-mail is addressed, for example, as in the mail opening information on the fifth and sixth rows of the mail opening table  140   a  shown in  FIG. 8 . 
     Furthermore, if an e-mail is addressed to a representative address (e.g., the e-mail identified by the mail number “01100002” on the second to fourth rows from the top of the mail opening table  140   a ), mail opening information is created for the group corresponding to the representative address (e.g., the group identified by the user ID “6”), and mail opening information is created for each of a plurality of users belonging to the group corresponding to the representative address (e.g., three users identified by the user IDs “1”, “2”, and “6”). 
     Then, each time a user logs in to the mail system and reads an e-mail, the mail server  100  obtains a date and time of opening (and minute and second, hereinafter the same throughout this specification), and the date and time of opening obtained is written as the date and time of opening in mail opening information corresponding to the mail number assigned to the e-mail read by the user and the user ID indicating the account of the user who opened the e-mail. In the case of an e-mail addressed to a group, if the e-mail has not been opened by all the users but has been opened by some users, “partially opened” is set as the date and time of the opening of the e-mail addressed to the group (e.g., the second row from the top of the mail opening table  140   a ). Then, when the e-mail has been opened by all the users to which the e-mail is addressed, similarly to the case of a personal user ID, a date and time of opening is written as the date and time of opening corresponding to the user ID of the group for the e-mail. 
     The mail opening information maintains records as to whether each e-mail managed by the mail server  100  has been opened by each user. Thus, with the mail server  100  according to this embodiment, it is possible to manage whether each e-mail has been read by each user. 
     Next, the procedure of a process executed by the mail system according to this embodiment will be described. First, a mailbox process that is executed when a user checks received e-mails in the mail server  100  according to this embodiment will be described. 
       FIG. 9  is a flowchart showing the procedure of the mailbox process. 
     Upon receiving an e-mail operation request sent from one of the terminal apparatuses  31 ,  32 , . . . (e.g., the terminal apparatus  31 ) used by a user belonging to the organization  30 , the mail server  100  according to this embodiment executes the mailbox process to provide the terminal apparatus with information of e-mails addressed to the user so that the information is displayed on the browser of the terminal apparatus. 
     In step S 11 , upon receiving an e-mail reading request from the user of the terminal apparatus  31 , the CPU  101  of the mail server  100  performs account authentication regarding the user ID of the personal account of the user via the LAN  10 . Upon successful account information, the user is allowed to log in to the mail system by the authenticated account. 
     In step S 12 , the CPU  101  accepts a user&#39;s instruction for selecting an account at which the user wishes to read e-mails, sent from the terminal apparatus  31 . Thus, the e-mail account at which the user wishes to read e-mails among the personal address and representative address is reported from one of the terminal apparatuses  31 ,  32 , . . . to the mail server  100 . 
     In step S 13 , the CPU  101  determines whether an operation end instruction sent from one of the terminal apparatuses  31 ,  32 , . . . has been accepted. If an operation instruction has not been accepted, the process proceeds to step S 14 . On the other hand, if an operation end instruction has been accepted, the process is exited. 
     In step S 14 , on the basis of the selecting instruction accepted in step S 12 , the CPU  101  obtains an account ID (see  FIG. 7 ) corresponding to the e-mail account selected by the user. Thus, when the user has selected to read e-mails at the personal address on the browser of one of the terminal apparatuses  31 ,  32 , . . . , an account ID corresponding to the personal address is obtained. On the other hand, when the user has selected to read e-mails at the representative address, an account ID corresponding to the representative address is obtained. 
     In step S 15 , the CPU  101  obtains mail information corresponding to the account ID obtained in step S 14 . 
     In step S 16 , the CPU  101  sends the mail information obtained in step S 15  to one of the terminal apparatuses  31 ,  32 , . . . at the source of the reading request from the user. 
     In step S 17 , the CPU  101  determines whether the user has created a reply mail on one of the terminal apparatuses  31 ,  32 , . . . at the account selected in step S 12 . If the user has created a reply mail, the process proceeds to step S 18 . On the other hand, if the user has not created a reply mail, the process proceeds to step S 12 . 
     In step S 18 , as a reply address that serves as a source of the reply mail (reply source) created by the user, the CPU  101  sets the mail address of the account ID obtained, which is the address of the account selected in step S 12 . This will be described later in detail with reference to  FIG. 15 . Thus, when the user replies to an e-mail at the personal address, the user creates a reply mail in which the personal address is set as a reply address. On the other hand, when the user replies to an e-mail at the representative address, the user creates a reply mail in which the representative address is set as a reply address. 
     In the embodiment described above, the mail server  100  sets a reply address before a user creates a reply mail. Without limitation, however, the mail server  100  may automatically change a reply address to a mail address of a corresponding account after a user creates a reply mail and issues a sending instruction, and then send the reply mail to a destination. Yet alternatively, instead of automatically changing the reply address, the mail server  100  may display an alert message or a confirmation message for the user or send an alert message or a confirmation message to a third party in a case where the destination address of the e-mail received does not coincide with the reply address of the reply mail created by the user. Furthermore, these schemes may be used in combination with each other. 
     Next, a process that is executed a user reads e-mails in the mail system according to this embodiment will be described. 
       FIG. 10  is a sequence diagram showing the procedure of the process executed when a user reads e-mails in the mail system. 
     In the mail system according to this embodiment, when a user in the organization  30  reads a Web mail by using one of the terminal apparatuses  31 ,  32 , . . . inside the organization  30  (e.g., the terminal apparatus  31 ), the following procedure is executed. The Web mail may be either an external mail sent to a personal user or group in the organization  30  from one of the terminal apparatuses  21 ,  22 ,  23 , . . . outside the organization  30  or an internal mail created for a personal user or group in the organization  30  at one of the terminal apparatuses  31 ,  32 , . . . inside the organization  30  (e.g., the terminal apparatus  31 ). 
     In step S 101 , the terminal apparatus  31  accepts input of an account ID and a password by a user in the organization  30 , and sends the account ID and the password to the mail server  100  via the LAN  10 . 
     In step S 202 , upon receiving the account ID and password sent from the terminal apparatus  31 , the mail server  100  performs account authentication on the basis of the account ID and password received in order to check the validity of the user. 
     In step S 203 , the mail server  100  obtains account information indicating an account associated with the account ID of the user who has logged in from the association-information storage unit  151 , the group-information storage unit  152 , and the address-information storage unit  153  of the account-information storage unit  150 . Thus, accounts at which the user who has logged in is allowed to read e-mails are identified. 
     In step S 204 , the mail server  100  sends information indicating the status of e-mails received at the accounts at which the user is allowed to read e-mails to the terminal apparatus  31  via the LAN  10 . The information indicating the status of e-mails includes mail opening information (see  FIG. 8 ). 
     In step S 105 , when the user has performed an operation on the browser to issue an instruction for reading e-mails at the user account corresponding to the personal address, the terminal apparatus  31  sends a user-account reading request to the mail server  100  via the LAN  10 . 
     In step S 206 , upon receiving the user-account reading request from the terminal apparatus  31 , the mail server  100  obtains mail information of the user account relevant to the user&#39;s request from the mail-information storage unit  130 . The mail information that is obtained is mail information of e-mails sent to the personal account of the user who has logged in. The mail information also includes data such as mail information of e-mails sent by the user in the past, the body of an e-mail being created, and so forth at the personal account of the user. 
     In step S 207 , the mail server  100  sends the mail information of the user account obtained in step S 206  to the terminal apparatus  31  via the LAN  10 . Upon receiving the mail information, the terminal apparatus  31  displays the content of e-mails and so forth on the browser. 
     In step S 108 , when the has performed an operation on the browser to issue an instruction for reading e-mails at a representative account corresponding to a representative address, the terminal apparatus  31  sends a representative-account reading request to the mail server  100  via the LAN  10 . 
     In step S 209 , upon receiving the representative-account reading request from the terminal apparatus  31 , the mail server  100  obtains mail information of the representative account relevant to the user&#39;s request from the mail-information storage unit  130 . The mail information that is obtained is mail information of e-mails sent to the representative address of the user who has logged in. The mail information also includes data such as mail information of e-mails sent by the user in the past, the body of an e-mail being created, and so forth at the representative account. 
     In step S 210 , the mail server  100  sends the mail information of the representative account obtained in step S 209  to the terminal apparatus  31  via the LAN  10 . Upon receiving the mail information, the terminal apparatus  31  displays the content of e-mails and so forth on the browser. 
     In step S 111 , upon receiving when the user has performed an operation on the browser to issue an instruction for creating a reply mail for an e-mail at the representative account, the terminal apparatus  31  sends a request for creating a reply mail at the representative account to the mail server  100  via the LAN  10 . 
     In step S 212 , upon receiving the representative-account reply-mail creating request sent from the terminal apparatus  31 , the mail server  100  sets the mail address of the representative account (representative address), which is the account specified in the reading request in step S 108 . Thus, the user creates a reply mail in which the representative address is set as a source address by the browser on the terminal apparatus  31 . 
     When the user creates a reply mail for an e-mail received at the personal address, similarly, the personal address is set as a reply address. 
     Next, display screens displayed on the browsers of the terminal apparatuses  31 ,  32 , . . . when the mailbox process is executed will be described. 
       FIG. 11  is an illustration showing a log-in screen. A log-in screen  350  shown in  FIG. 12  is an example of a log-in screen displayed on a browser on a monitor (not shown) connected to one of the terminal apparatuses  31 ,  32 , . . . (e.g., the terminal apparatus  31 ) operated by a user inside the organization  30  when the user performs a log-in operation for logging into the mail system in order to read e-mails. 
     The log-in screen  350  includes an ID input field  351   a , a password input field  351   b  for accepting input of a password, a log-in button  351   c  for accepting an operation for causing the mail server  100  to execute account authentication for log in when the ID and password input to the ID input field  351   a  and the password input field  351   b  are valid, and a clear button  351   d  for accepting an operation for canceling information that has been input when the ID and password input to the ID input field  351   a  and the password input field  351   b  are not valid. 
     A user who logs into the mail system inputs a user ID assigned in advance to the ID input field  351   a  and a password associated with the user ID to the password input field  351   b , and then operates the log-in button  351   c . Accordingly, the mail server  100  executes account authentication, so that the user is allowed to log into the mail system. 
       FIG. 12  is an illustration showing a post-log-in screen. A post-log-in screen  360  shown in  FIG. 12  is an example of a post-log-in screen displayed on the browser on the monitor (not shown) connected to one of the terminal apparatuses  31 ,  32 , . . . (e.g., the terminal apparatus  31 ) operated by the user in the organization  30  immediately after the user logs into the mail system to read e-mails. 
     The post-log-in screen  360  includes account selecting buttons  361   a ,  361   b , and  361   c  for accepting an operation for selecting an account, a close button  361   d  for accepting an operation for quitting reading e-mails, a folder display area  362  for displaying the status of e-mail folders at accounts at which the user is allowed to perform operations, and an account-information display area  363  for displaying the status of reception of e-mails at the account that the user has logged into. 
     In the folder display area  362 , accounts at which the user is allowed to read e-mails (e.g., “personal”, “B section”, and “C subsection”), and folders at the accounts (e.g., “inbox”, “sent items”, “deleted items”, “forms”, and “complaints”) are displayed. 
     In the folder display area  362 , for each of the personal and representative addresses corresponding to the accounts at which the user is allowed to read e-mails, the number of unopened (unread) mails at the account is displayed on a folder-by-folder basis. 
     More specifically, referring to  FIG. 12 , “Inbox (10)” for the personal address indicates that 10 unopened mails exist in the inbox folder of the personal address. Furthermore, “Inbox (25)” for the B section indicates that 25 unopened mails exist in the user&#39;s account at the representative address of the B section. The mail server  100  can determine whether each e-mail has been opened or not with reference to the mail opening information stored in the mail opening table  140   a  (see  FIG. 8 ). 
     In the account-information display area  363 , the mail address of the account that the user has logged into, and the status of reception at the mail address, such as the number of unopened mails and the amount of storage currently used, are displayed. For example, in the case where the user has logged in with the personal address, the status of reception at the personal address is displayed in the account-information display area  363 . 
     The user who has logged into the mail system can recognize the presence or absence of unopened mails and the number of unopened mails at each account with reference to the folder display area  362 . In the case where the user reads e-mails at an account having any unopened mail, the user can switch to account display screens  370  and  380 , which will be described later in detail with reference to  FIGS. 13 and 14 , by operating one of the account selecting buttons  361   a ,  361   b , and  361   c  corresponding to an account at which the user wishes to read e-mails. If the user does not wish to read e-mails at any of the accounts, the user can log out of the mail system by operating the close button  361   d.    
       FIG. 13  is an illustration showing an account display screen for a personal address. The account display screen  370  shown in  FIG. 13  is an example of an account display screen displayed on the browser on the monitor (not shown) connected to one of the terminal apparatuses  31 ,  32 , . . . (e.g., the terminal apparatus  31 ) operated by the user inside the organization  30 , showing e-mails received at the personal address. 
     Similarly to the post-log-in screen  360 , the account display screen  370  includes account selecting buttons  371   a ,  371   b , and  371   c , a close button  371   d , and a folder display area  372 . Furthermore, in the account display screen  370 , a list display area  373  for displaying a list of e-mails in a folder selected in the folder display area  372 , a body display area  374  for displaying the body of an e-mail selected in the list display area  373 , and a reply button  375  that is operated by the user when the user creates a reply to the e-mail displayed in the body display area  374  are provided. 
     In  FIG. 13 , the account selecting button  371   a , corresponding to the personal account, is displayed in white. On the other hand, the other account selecting buttons  371   b  and  371   c  are displayed as shaded. This indicates that the account of e-mails displayed in the list display area  373  is the personal account. The user can switch the e-mails displayed to e-mails of other accounts corresponding to the account selecting buttons  371   b  and  371   c  by operating the account selecting buttons  371   b  and  371   c . Furthermore, the user can log out of the mail server and close the display of e-mails by operating the close button  371   d.    
     When the user wishes to create a reply mail to an e-mail viewed at the personal account displayed in the body display area  374 , the user operates the reply button  375  to open a reply-mail creating screen  390 , which will be described later in detail with reference to  FIG. 16 . 
       FIG. 14  is an illustration showing an account display screen for a representative address. The account display screen  380  shown in  FIG. 14  is an example of an account display screen displayed on the browser on the monitor (not shown) connected to one of the terminal apparatuses  31 ,  32 , . . . (e.g., the terminal apparatus  31 ) operated by the user inside the organization  30 , showing e-mails received at the representative address of the B section, which is one of the representative addresses. 
     Similarly to the account display screen  370  shown in  FIG. 13 , the account display screen  380  includes account selecting buttons  381   a ,  381   b , and  381   c , a close button  381   d , a folder display area  382 , a list display area  383 , a body display area  384 , and a reply button  385 . 
     In  FIG. 14 , the account selecting button  381   b , corresponding to the representative account of the B section, is displayed in white. On the other hand, the other account selecting buttons  381   a  and  381   c  are displayed as shaded. This indicates that the account of e-mails displayed in the list display area  383  is the representative account of the B section. The user can switch the e-mails displayed to e-mails of other accounts corresponding to the account selecting buttons  381   a  and  381   c  by operating the account selecting buttons  381   a  and  381   c . Furthermore, the user can log out of the mail server and close the display of e-mails by operating the close button  381   d.    
     When the user wishes to create a reply mail to an e-mail viewed at the representative account displayed in the body display area  384 , the user operates the reply button  385  to open a reply-mail creating screen  390 , which will be described later in detail with reference to  FIG. 15 . 
       FIG. 15  is an illustration showing a reply-mail creating screen. A reply-mail creating screen  390  shown in  FIG. 15  is an example of a reply-mail creating screen displayed on the browser on the monitor (not shown) connected to one of the terminal apparatuses  31 ,  32 , . . . (e.g., the terminal apparatus  31 ) operated by the user inside the organization  30  when the user creates a reply mail to an e-mail that the user has read. 
     The reply-mail creating screen  390  includes a close button  391 , a source-address input field  392  for accepting input of a sender address at the source of the reply mail (reply source), a body input area  393  for accepting input of a body of the reply mail, and a send button  394  that is operated by the user when sending the reply mail that has been created. 
     Referring to  FIG. 13  or  14 , when the user has read the e-mail displayed in the body display area  374  or  384  and then wishes to create a reply mail to the e-mail, the user operates the reply button  375  or  385  to open the reply-mail creating screen  390  on the browser at the terminal apparatus  31 . The user can create a reply mail to the e-mail by entering a mail body in the body input area  393 . 
     In the source-address input field  392 , the mail address of the account at which the e-mail to which a reply mail is being created was read is input in advance. More specifically, for example, as shown in  FIG. 14 , when the user creates a reply mail to an e-mail read at a representative account, as shown in  FIG. 15 , the representative address, i.e., the mail address of the representative account at which the e-mail was read, is input as a source address. When the user creates a reply mail to an e-mail read at the personal account as shown in  FIG. 13 , the personal address, i.e., the mail address of the personal account at which the e-mail was read, is input as a source address. 
     Thus, an appropriate source address is set to the reply mail created by the mail system. Accordingly, it is possible to prevent a mistake of sending an e-mail in which another account of the user is set as a source address (sender). This serves to prevent corresponding leakage of a personal address to the outside. For example, it is possible to prevent it from being accidentally known to the outside which user in the organization  30  sent the e-mail, so that personal information can be protected. 
     Furthermore, users registered at the mail server  100  can readily share information regarding e-mails addressed to a representative address, which has not been possible in existing Web mail systems. 
     Furthermore, in addition to information displayed in existing systems when a user has logged in to a personal account, it is possible to visually recognize the status of reception of e-mails at a representative address. 
     As described above, since it is possible to perform switching of e-mail information provided among a plurality of accounts according to a switching instruction by the user, it is possible to perform switching of display regarding e-mails among the plurality of accounts according to a switching instruction by the user at a terminal apparatus inside the organization  30 . This facilitates user&#39;s reading of e-mails at a plurality of mail accounts. 
     Furthermore, since the presence or absence of any unopened mails and the number of unopened mails are displayed in the post-log-in screen  360  and the account display screens  370  and  380  even for an account different from an account for which mail information is displayed, without selecting all the accounts one by one, it is possible to determine whether mail information of other accounts should be displayed. This serves to reduce user&#39;s tasks for mail management. 
     Hereinabove, a mail sending and receiving program, a mail sending and receiving apparatus, and a mail sending and receiving system according to an embodiment of the present invention have been described. Although the above description explains the principle of the present invention merely, the present invention is not limited to the exact exemplary configurations and applications described above. It is to be understood that various modifications and alternatives can be conceived by those skilled in the art. All corresponding modifications, alternatives, and equivalents are considered as falling in the scope of the present invention as claimed and its equivalents. The configuration of individual parts can be replaced with arbitrary configurations having similar functions. Furthermore, arbitrary configurations or steps may be added when embodying the present invention. Furthermore, the present invention covers a combination of arbitrary two or more configurations (features) of the embodiments described above. 
     The above processing functions can be implemented by a computer. In that case, a program defining processing for intended functions of the mail server  100  is provided. The processing functions are implemented on a computer by executing the program on the computer. 
     The program defining the processing can be recorded on a computer-readable medium. The computer-readable medium is, for example, a magnetic recording medium, an optical disc, a magneto-optical recording medium, or a semiconductor memory. The magnetic recording medium is, for example, an HDD, an FD (flexible disk), or an MT (magnetic tape). The optical disc is, for example, a DVD (digital versatile disc), a DVD-RAM, a CD-ROM (compact disc read-only memory), or a CD-R (recordable)/RW (rewritable). The magneto-optical recording medium is, for example, an MO (magneto-optical disk). 
     In order to distribute the program, for example, a portable recording medium having the program recorded thereon, such as a DVD or CD-ROM, is sold. Alternatively, the program may be stored at a server computer and transferred from the server computer to another computer via a network. 
     For example, a computer that executes the program installs the program recorded on the portable recording medium or transferred from the server computer on a storage device of its own. Then, the computer reads the program from the storage device and executes processing according to the program. Alternatively, the computer may read the program directly from the portable recording medium and execute processing according to the program. Yet alternatively, the computer may execute processing according to the program each time upon receiving the program from the server computer.