JP4844527B2 - Communication system, information processing apparatus, and program - Google Patents

Description

  The present invention relates to a communication system including a plurality of server devices that function as mail servers.

Japanese Patent Application Laid-Open No. 2004-228561 discloses a technique for making a call via a PhoneGate server in order to enable a call by an Internet telephone between terminals having only a private IP address. That is, in such a situation, since each terminal cannot directly access the counterpart terminal, each terminal uploads its own call data to the PhoneGate server. As a result, the PhoneGate server acquires the call data generated at each terminal, and the call is established when each terminal downloads and plays the call data from the PhoneGate server.
JP 2004-172771 A

By the way, even in communication between mail servers that perform transmission / reception of e-mails, a situation may occur in which direct access from the transmission source mail server to the transmission destination mail server is not possible.
However, the configuration described in Patent Document 1 described above relates to the Internet telephone, and since it is assumed that each terminal and the PhoneGate server are always connected, communication is performed only when necessary like a mail server. It cannot be applied directly to the environment.

  The present invention has been made in view of these problems, and an object of the present invention is to make it possible to send an electronic mail to a mail server in which access from an external network is restricted.

The communication system of the first configuration made to achieve the above object is configured such that a plurality of server devices functioning as mail servers and a relay device that relays communication between server devices can communicate with each other. is there.

  Then, the server device periodically transmits communication means for periodically communicating with the relay device, and mail transmitting means for requesting the relay device to relay the electronic mail when transmitting the electronic mail to another server device. With.

  In addition, when the relay device is requested to relay an e-mail from the server device, the communication with the relay device by the requesting server device and the communication with the relay device by the server device to which the e-mail is transmitted overlap. Adjusting means for adjusting to be performed at the timing, and relay means for relaying the e-mail transmitted from the requesting server apparatus to the destination server apparatus at the timing adjusted by the adjusting means, Is provided.

  According to such a communication system, an e-mail can be transmitted to a server apparatus in which access from an external network is restricted by a NAT (Network Address Translation), a firewall, or the like.

Further, in the communication system having the second configuration , when the server device is requested to relay the e-mail, the adjustment unit matches the timing of communication that the destination server device periodically performs with respect to the relay device. The transmission timing is notified to the requesting server device, and the mail transmission means transmits an e-mail to the relay device at the transmission timing notified from the relay device.

  According to such a communication system, the e-mail from the request source server apparatus is relayed to the transmission destination server apparatus using the communication periodically performed by the transmission destination server apparatus to the relay apparatus as it is. Can do.

In the communication system of the third configuration , the mail transmission means requests the relay device to relay the email at the transmission time when transmitting the email with the specified transmission time to another server device. Then, the adjustment means adjusts so that when the server device requests relay of the e-mail at the transmission time, the destination server device communicates with the relay device at a timing matched with the transmission time. To do.

According to such a communication system, an e-mail from a request source server device can be relayed to a destination server device at a specified transmission time.
Further, in the communication system of the fourth configuration , the adjustment unit is configured to communicate with the relay device from at least one of the request source server device and the transmission destination server device at the adjusted timing. The readjustment is performed so that the communication with the relay device by the requesting server device and the communication with the relay device by the destination server device are performed at overlapping timings.

  According to such a communication system, when the e-mail cannot be relayed for some reason, the e-mail is not transmitted due to a temporary cause because the relay is tried again.

Next, an information processing apparatus having a fifth configuration is used as a server apparatus in a communication system configured such that a plurality of server apparatuses functioning as mail servers and a relay apparatus that relays communication between server apparatuses can communicate with each other. It is The information processing apparatus includes a periodic communication unit that periodically communicates with the relay apparatus, and a mail that requests the relay apparatus to relay the e-mail when the e-mail is transmitted to another server apparatus. Transmitting means.

According to such an information processing apparatus, the communication system having the first configuration can be constructed, and thereby the above-described effects can be obtained.
Next, an information processing apparatus having a sixth configuration is used as a relay apparatus in a communication system in which a plurality of server apparatuses functioning as mail servers and a relay apparatus that relays communication between server apparatuses can communicate with each other. It is When the server device is requested to relay an email, the information processing device performs communication between the requesting server device to the relay device and communication between the email destination server device to the relay device. An adjustment unit that adjusts to be performed at an overlapping timing, and a relay that relays an e-mail transmitted from the request source server device to the destination server device at the timing adjusted by the adjustment unit Means.

According to such an information processing apparatus, the communication system having the first configuration can be constructed, and thereby the above-described effects can be obtained.
Next, a program having a seventh configuration functions as a server device in a communication system in which a plurality of server devices functioning as mail servers and a relay device that relays communication between server devices are configured to communicate with each other. It is for making it happen. The program includes a periodic communication unit that periodically communicates with the relay device, and a mail transmission unit that requests the relay device to relay the e-mail when the e-mail is transmitted to another server device. As a computer to function.

According to such a program, it is possible to cause the computer to function as the information processing apparatus having the fifth configuration , thereby obtaining the effects described above.
Next, a program having an eighth configuration functions as a relay device in a communication system in which a plurality of server devices that function as mail servers and a relay device that relays communication between server devices can communicate with each other. It is for making it happen. In this program, when the server device requests relaying of the email, the communication to the relay device by the requesting server device and the communication to the relay device by the server device to which the email is transmitted are duplicated. As an adjustment unit that adjusts to be performed at the timing, and a relay unit that relays an e-mail transmitted from the request source server device to the destination server device at the timing adjusted by the adjustment unit Make the computer work.

According to such a program, it is possible to cause the computer to function as the information processing apparatus having the sixth configuration , thereby obtaining the effects described above.

Embodiments to which the present invention is applied will be described below with reference to the drawings.
[1. overall structure]
FIG. 1 is a block diagram illustrating a schematic configuration of a communication system according to an embodiment.

As shown in the figure, this communication system is configured such that a plurality of mail servers 10, 10,... And an authentication server 30 are capable of data communication via the Internet 50.
[1-1. Role of mail server and authentication server in communication system]
Here, first, main roles of the mail server 10 and the authentication server 30 in this communication system will be briefly described. Details of each content will be described later.

<Role of mail server>
In order to have the authentication server 30 prove that it is a legitimate mail server, an inquiry is made to the authentication server 30 at the time of activation.
Inquires the authentication server 30 periodically.
-Send and receive e-mail to and from other mail servers 10.
-Inquires the authentication server 30 at the time of mail transmission and obtains permission for mail transmission.
-E-mail reservation transmission (transmission at the transmission time specified by the user).

<Role of authentication server>
-Authentication of the mail server 10 is performed. And the mail transmission of the mail server 10 which passed authentication is permitted, and the mail transmission of the mail server 10 which is unsuccessful is prohibited.
-DNS (Domain Name System) solution of the mail server 10 is performed. That is, the mail server 10 makes an inquiry to the authentication server 30 to know the destination IP address when sending an electronic mail to another mail server 10. A detailed description of DNS resolution will be omitted.
In a state where both the transmission side mail server 10 and the reception side mail server 10 have a session with the authentication server 30, the electronic mail from the transmission side mail server 10 is relayed and transmitted to the reception side mail server 10. Specifically, when the sending mail server 10 sends an e-mail to the receiving mail server 10, if the sending mail server 10 makes a DNS resolution inquiry to the authentication server 30, the sending mail server 10 asks the sending mail server 10. The receiving side mail server 10 notifies the authentication server 30 to make an inquiry in accordance with the next timing for making an inquiry to the authentication server 30. However, in the case of reserved transmission mail, the inquiry time of the receiving mail server 10 is designated. For example, in the case of an e-mail reserved for transmission at 10:00, it is determined that an inquiry at 9:59 is unnecessary, and an inquiry is specified at the next inquiry so that an inquiry is made at 10:00.
If the inquiry from at least one of the transmission side mail server 10 and the reception side mail server 10 does not come at the specified time, the inquiry time is reset. However, if there is no improvement even after a certain period of time has elapsed since the first designated time, the process ends.

[1-2. Mail server configuration]
Next, the configuration of the mail server 10 will be described.
In this communication system, each mail server 10 includes a relatively small number of terminal devices (for example, personal computers) existing in a small network (local area) constructed by a general household or SOHO (Small Office / Home Office). Functions as a mail server. In this embodiment, a multifunction machine having a mail server function in addition to a telephone (voice communication) function, a scanner function, a printer function, a copy function, an Internet facsimile function, and the like is used as the mail server 10.

FIG. 2 is a block diagram showing a schematic configuration of the mail server 10 which is a multifunction machine.
As shown in the figure, the mail server 10 includes a control unit 11, a sound input unit 15, a sound output unit 16, a communication unit 17, an operation unit 18, a display unit 19, an image reading unit 20, an image printing unit 21, and a storage unit. 22 is provided.

The control unit 11 is mainly configured by a microcomputer including a CPU 12, a ROM 13, a RAM 14, and the like, and comprehensively controls each unit constituting the mail server 10.
The sound input unit 15 inputs sound from a microphone provided in a handset (not shown) included in the mail server 10 and outputs the sound to the control unit 11.

The sound output unit 16 outputs sound from a speaker (not shown) provided in the handset or the mail server 10 based on a command from the control unit 11.
The communication unit 17 performs data transmission / reception processing via the communication cable in a state where the communication cable (LAN cable) is connected. That is, for data communication with an external device, for example, with a terminal device (not shown) in the LAN, other mail server 10 or authentication server 30 connected via the Internet 50 Data communication is possible between the two.

  The operation unit 18 is for inputting a command by an external operation from the user, and includes various operation buttons (not shown). Then, the operation unit 18 outputs the content of the external operation performed with the operation button to the control unit 11.

  The display unit 19 is for displaying various types of information to the user, and includes a liquid crystal display (not shown). And the display part 19 displays information, such as a message and an image, based on the instruction | command from the control part 11. FIG.

The image reading unit (scanner) 20 reads an image of a document set at a predetermined document reading position based on a command from the control unit 11 and generates image data representing the image.
The image printing unit (printer) 21 prints a color image on a printing medium such as paper based on a command from the control unit 11. Examples of the image printed by the image printing unit 21 include an image read by the image reading unit 20, an image received by a facsimile function, and an image received from an external device such as a terminal device.

  The storage unit 22 stores various data in a hard disk (not shown) or a memory in which stored information cannot be rewritten. Specifically, a program for causing the CPU 12 to execute processing (FIGS. 8 to 10) described later is stored in the hard disk. In addition, in a memory in which stored information cannot be rewritten, an ID (identification information of the mail server 10, for example, a manufacturing number or a MAC address) and a password are stored in advance as information unique to each mail server 10. Among these, at least the password cannot be read from the outside of the mail server 10.

[1-3. Configuration of authentication server]
Next, the configuration of the authentication server 30 will be described.
FIG. 3 is a block diagram illustrating a schematic configuration of the authentication server 30.

As shown in the figure, the authentication server 30 includes a control unit 31, a communication unit 35, and a storage unit 36.
The control unit 31 is configured mainly with a microcomputer including a CPU 32, a ROM 33, a RAM 34, and the like, and comprehensively controls each unit configuring the authentication server 30.

The communication unit 35 performs data transmission / reception processing via the Internet 50.
The storage unit 36 stores various data in a hard disk (not shown) or a memory in which stored information cannot be rewritten. Specifically, a program for causing the CPU 12 to execute processing (FIGS. 11 to 13) described later is stored in the hard disk.

  Further, in the memory in which stored information cannot be rewritten, the ID and password of each mail server 10 (stored in each mail server 10 as information of a plurality of mail servers 10 managed by the authentication server 30). The same information as the ID and password is stored in advance. In the present embodiment, as described above, a multifunction machine having a mail server function is used as the mail server 10, and such a mail server 10 is a management target of the authentication server 30. Specifically, for example, a case where the information of each mail server 10 is managed by the authentication server 30 operated by the manufacturer of the mail server (multifunction machine) 10 can be considered.

  Furthermore, a registration server database (registration server DB), which is a database for registering and managing information related to the mail server 10 to be managed, is stored in the hard disk (storage means capable of rewriting stored information) of the storage unit 36. Has been.

  This registration server database is for registering only the mail servers 10 that are reliable (for example, do not transmit spam mail) among the mail servers 10 to be managed. Specifically, the authentication server 30 registers information (server information) regarding the mail server 10 in the registration server database by receiving a registration request from the mail server 10 to be managed. After that, when it is found that the mail server 10 whose server information is registered in the registered server database has transmitted junk mail, the server information of the mail server 10 is deleted from the registered server database. Specifically, it can be realized by automatically deleting it based on the notification from the mail server 10 that received the junk mail, or by the administrator of the authentication server 30 deleting it artificially.

The server information includes the ID and IP address of the mail server 10.
[2. Processing realized in communication system]
Next, processing realized by the communication system of this embodiment will be described.

  As described above, in this communication system, each mail server 10 functions as a mail server for a relatively small number of terminal devices existing in a small-scale network constructed by a general household or SOHO. In such a mail server 10, a private IP address is used instead of a global IP address, and it is considered that access from an external network is restricted by a NAT, a firewall, or the like. In this case, a direct session from a mail server 10 (hereinafter also referred to as “transmitting mail server”) 10 to a mail server 10 (hereinafter also referred to as “receiving mail server”) as an email transmission destination. I can not put up. Therefore, in the communication system of the present embodiment, it is possible to send and receive e-mail between the mail servers 10 even in such an environment.

Here, an outline of mail transmission / reception processing performed in the communication system will be described.
[2-1. Email transmission / reception processing example (1)]
First, a mail transmission / reception process when a session can be established from the sending mail server 10 to the receiving mail server 10 and when the sending mail server 10 transmits a normal e-mail that is not a reserved sending mail is shown in FIG. 4 will be described.

  The sending mail server 10 that is going to send an e-mail makes an authentication request (e-mail sending request) to the authentication server. Then, the authentication server 30 transmits an authentication OK authentication result to the transmission side mail server 10.

  Then, the authentication server 30 notifies the transmission side mail server 10 of transmission permission. Thereby, the transmission side mail server 10 directly transmits an electronic mail to the reception side mail server 10, and the reception side mail server 10 receives the electronic mail.

[2-2. Email transmission / reception processing example (2)]
Next, a mail transmission / reception process when a session can be established from the transmission side mail server 10 to the reception side mail server 10 and the transmission side mail server 10 transmits a reserved transmission mail will be described with reference to FIG. explain.

  The sending mail server 10 that is going to send an e-mail makes an authentication request (e-mail sending request) to the authentication server. Then, the authentication server 30 transmits an authentication OK authentication result to the transmission side mail server 10.

  Thereafter, when the transmission time specified by the reserved transmission mail comes, the authentication server 30 notifies the transmission side mail server 10 of transmission permission. Thereby, the transmission side mail server 10 directly transmits an electronic mail to the reception side mail server 10, and the reception side mail server 10 receives the electronic mail.

[2-3. Email transmission / reception processing example (3)]
Next, regarding a mail transmission / reception process when a session cannot be established from the sending mail server 10 to the receiving mail server 10 and the sending mail server 10 transmits a normal e-mail that is not a reserved sending mail, This will be described with reference to FIG.

  The sending mail server 10 that is going to send an e-mail makes an authentication request (e-mail sending request) to the authentication server. Then, the authentication server 30 transmits an authentication OK authentication result to the transmission side mail server 10.

  Then, the authentication server 30 designates a transmission time that matches the inquiry time from the reception side mail server 10 to the transmission side mail server 10. As a result, the transmission side mail server 10 and the reception side mail server 10 can establish a session to the authentication server 30 at the same time. At this time, the electronic mail transmitted by the transmission side mail server 10 is converted into the authentication server. 30 can be relayed and received by the receiving mail server 10.

[2-4. Email transmission / reception processing example (4)]
Next, a mail transmission / reception process when the transmission side mail server 10 transmits a reserved transmission mail when a session cannot be established from the transmission side mail server 10 to the reception side mail server 10 will be described with reference to FIG. explain.

  The sending mail server 10 that is going to send an e-mail makes an authentication request (e-mail sending request) to the authentication server. Then, the authentication server 30 transmits an authentication OK authentication result to the transmission side mail server 10.

  Then, the transmission side mail server 10 specifies the transmission time specified by the reserved transmission mail to the authentication server 30. At the time of an inquiry from the receiving mail server 10, the authentication server 30 notifies the receiving mail server 10 to establish a session at the transmission time. As a result, the transmission side mail server 10 and the reception side mail server 10 can establish a session to the authentication server 30 at the same time. At this time, the electronic mail transmitted by the transmission side mail server 10 is converted into the authentication server. 30 can be relayed and received by the receiving mail server 10.

[3. Processing executed by control unit]
Next, the specific content of the process which the mail server 10 and the authentication server 30 perform in the communication system of this embodiment is demonstrated.

[3-1. Registration request processing]
First, registration request processing executed by the CPU 12 of the mail server 10 will be described with reference to the flowchart of FIG. This registration request process is started when the mail server 10 is activated.

When starting the registration request process, the CPU 12 first performs a process of establishing a session with the authentication server 30 in S101.
Subsequently, in S102, a registration request, which is a request for registering its own server information in the registration server database, is made to the authentication server 30. At this time, its own ID is transmitted to the authentication server 30. Thereby, the authentication server 30 starts a registration process (FIG. 11) described later.

  Subsequently, in S103, challenge / response authentication processing is performed with the authentication server 30. Specifically, the authentication server 30 transmits a challenge code to the mail server 10 that is the registration request source. Then, the registration request source mail server 10 synthesizes the received challenge code and the password stored in advance according to a specific algorithm, creates a response, and transmits the response to the authentication server 30. The authentication server 30 also creates a response in the same manner from the transmitted challenge code and the password stored in advance for the mail server 10 and matches the response received from the mail server 10. Authentication OK (success).

  Subsequently, in S104, it is determined whether or not its own server information is registered in the registration server database. Specifically, when registration OK information is transmitted from the authentication server 30, it is determined that it is registered, and when error information is transmitted, it is determined that it is not registered. The registration OK information and error information are transmitted based on the processing of S404 and S405 in the registration processing (FIG. 11) described later.

  If it is determined in S104 that the server information is not registered in the registered server database, the process proceeds to S105, and error processing such as displaying an error message on the display unit 19 is performed. Thereafter, the process proceeds to S106.

On the other hand, if it is determined in S104 that its own server information is registered in the registration server database, the process proceeds to S106 as it is.
In S106, processing for disconnecting the session with the authentication server 30 is performed. Thereafter, the registration request process ends.

  Thus, each mail server 10 registers its own server information in the registration server database by making a registration request to the authentication server 30 at startup. As a result, the authentication server 30 can perform name resolution for requests from other mail servers 10. That is, the mail server 10 can receive an e-mail by authentication at the time of activation.

[3-2. Inquiry processing]
Next, inquiry processing executed by the CPU 12 of the mail server 10 will be described with reference to the flowchart of FIG. This inquiry process is started when the mail server 10 is activated, and the processes of S202 to S209 are performed each time the inquiry timing comes (S201: YES), as will be described later.

  When starting the inquiry process, the CPU 12 first determines whether or not the timing for making an inquiry to the authentication server 30 has arrived in S201, and proceeds to S202 if it is determined that the timing for making an inquiry has come. Note that the timing for inquiring may be, for example, a certain time after the previous communication or every predetermined time.

In S202, a process for establishing a session to the authentication server 30 is performed.
Subsequently, in S203, it is determined whether or not a session time notification is received from the authentication server 30. The notification of the session time is performed based on the processes of S512 and S519 in the mail transmission process (FIG. 12) described later.

  If it is determined in S203 that a session time notification has been received from the authentication server 30, the process proceeds to S204, and the inquiry timing (inquiry schedule is set so that the authentication server 30 is inquired at the notified session time. Time). Thereafter, the process proceeds to S205.

On the other hand, if it is determined in S203 that the notification of the session time has not been received from the authentication server 30, the process proceeds to S205 as it is.
In S205, it is determined whether or not an e-mail (e-mail from the sending mail server 10 relayed by the authentication server 30) has been received. The electronic mail is transmitted based on the process of S517 in the mail transmission process (FIG. 12) described later.

If it is determined in S205 that an e-mail has been received, the process proceeds to S206, and an e-mail receiving process is performed. Thereafter, the process proceeds to S207.
On the other hand, if it is determined in S205 that no e-mail has been received, the process proceeds to S207.

In S207, it is determined whether or not other information (information other than the session time notification and received mail) has been received.
If it is determined in step S207 that other information has been received, the process proceeds to step S208, and processing corresponding to the received information is performed. Thereafter, the process proceeds to S209.

On the other hand, if it is determined in S207 that no other information has been received, the process proceeds to S209.
In S209, a process for disconnecting the session with the authentication server 30 is performed. Thereafter, the process returns to S201.

[3-3. Send request processing]
Next, transmission request processing executed by the CPU 12 of the mail server 10 will be described with reference to the flowchart of FIG. This transmission request process is started when an electronic mail is transmitted to another mail server 10.

When starting the transmission request process, the CPU 12 first performs a process of establishing a session with the authentication server 30 in S301.
Subsequently, in S <b> 302, a transmission request (also an authentication request), which is an e-mail transmission request (relay request) to another mail server 10, is sent to the authentication server 30. As a result, the authentication server 30 starts mail transmission processing (FIG. 12) described later. If the e-mail to be transmitted is a reservation e-mail (an e-mail with a specified transmission time), transmission at the specified transmission time is requested.

Subsequently, in S303, the above-described challenge / response authentication process is performed with the authentication server 30.
Subsequently, in S304, it is determined whether or not the authentication is successful as a result of the authentication process. Specifically, when an authentication OK authentication result is transmitted from the authentication server 30, it is determined that the authentication is OK, and when an authentication rejection authentication result is transmitted, it is determined that the authentication is not OK. To do. This authentication result is transmitted based on the processing of S503 and S509 in the mail transmission processing (FIG. 12) described later.

  If it is determined in S304 that the authentication is OK, the process proceeds to S305, and whether or not the mail server (transmitting mail server) 10 can directly establish a session with the receiving mail server 10 is determined. judge. Specifically, when a determination result indicating that a session can be established is transmitted from the authentication server 30, it is determined that a session can be established, and a determination result that a session cannot be established is transmitted. If it does, it is determined that a session cannot be established. This determination result is transmitted based on the processes in S505 and S510 in the mail transmission process (FIG. 12) described later.

  If it is determined in S305 that a session can be established directly to the receiving mail server 10, the process proceeds to S306, where it is determined whether the electronic mail to be transmitted is a reserved transmission mail.

If it is determined in S306 that the e-mail to be transmitted is a reserved transmission e-mail, the process proceeds to S307 and a process for disconnecting the session with the authentication server 30 is performed.
Subsequently, in S308, an authentication request is made after a process of establishing a session to the authentication server 30 at the designated transmission time. Thereafter, the process proceeds to S309.

On the other hand, if it is determined in S306 that the electronic mail to be transmitted is not a reserved transmission mail, the process proceeds to S309 as it is.
In S309, it is determined whether or not a transmission permission notification is received from the authentication server 30. The transmission permission notification is transmitted based on the processing of S508 in the mail transmission processing (FIG. 12) described later.

  If it is determined in S309 that a transmission permission notification has been received from the authentication server 30, the process proceeds to S310, and the e-mail is directly transmitted to the receiving mail server 10. As a result, the receiving mail server 10 receives the e-mail. Thereafter, the process proceeds to S312.

  On the other hand, if it is determined in S304 that the authentication is not successful, or if it is determined in S309 that the transmission permission notification has not been received, the process proceeds to S311 and error processing such as displaying an error message on the display unit 19 is performed. . Thereafter, the process proceeds to S312.

In step S312, a process for disconnecting the session with the authentication server 30 is performed. Thereafter, the transmission request process is terminated.
On the other hand, if it is determined in S305 that it is not possible to establish a direct session with the receiving mail server 10, the process proceeds to S313 and the authentication server 30 receives a notification of the session time. The notification of the session time here is performed based on the processing of S512 and S513 in the mail transmission processing (FIG. 12) described later.

Subsequently, in S314, a process for disconnecting the session with the authentication server 30 is performed.
Subsequently, in S315, a process for establishing a session to the authentication server 30 at the notified session time is performed.

  Subsequently, in S316, it is determined whether or not a transmission permission notification is received from the authentication server 30. Note that the transmission permission notification is made in S516 in the mail transmission process (FIG. 12) to be described later when the authentication server 30 can relay the electronic mail from the transmitting mail server 10 to the receiving mail server 10. Sent based on processing.

  If it is determined in S316 that a transmission permission notification has been received from the authentication server 30, the process proceeds to S317, and an e-mail is transmitted to the authentication server 30. As a result, the e-mail is relayed by the authentication server 30 and received by the receiving mail server 10. Thereafter, the process proceeds to S312 to perform a process of disconnecting the session with the authentication server 30, and then the present transmission request process is terminated.

  On the other hand, if it is determined in S316 that the transmission permission notification has not been received from the authentication server 30, the process proceeds to S318, and it is determined whether or not the session time notification has been received from the authentication server 30. Note that the notification of the session time here cannot be in a state where the authentication server 30 can relay the email, and when relay retry is performed, the notification of S519 in the mail transmission process (FIG. 12) described later is performed. Performed based on processing.

  If it is determined in S318 that the session time has been received from the authentication server 30, the process returns to S314. In other words, a process of once disconnecting the session and establishing a session again at the newly notified session time is performed.

  On the other hand, if it is determined in S318 that the notification of the session time has not been received from the authentication server 30, the process proceeds to S319, and it is determined whether or not an error notification has been received from the authentication server 30. Note that the error notification is performed based on the process of S520 in the mail transmission process (FIG. 12) to be described later when it is not possible to relay the e-mail even after retrying for a certain time.

If it is determined in S319 that no error notification has been received from the authentication server 30, the process returns to S316.
On the other hand, if it is determined in S319 that an error notification has been received from the authentication server 30, the process proceeds to S320, and error processing such as displaying an error message on the display unit 19 is performed. Thereafter, the process proceeds to S312 to perform a process of disconnecting the session with the authentication server 30, and then the present transmission request process is terminated.

[3-4. registration process]
Next, registration processing executed by the CPU 32 of the authentication server 30 when a registration request is received from the mail server 10 will be described with reference to the flowchart of FIG. The registration request is transmitted together with the ID of the mail server 10 that is the registration request source based on the process of S102 in the above-described registration request process (FIG. 8).

  When starting the registration process, the CPU 32 first performs the above-described challenge / response authentication process with the mail server 10 as the registration request source in S401. Also, the registration request source mail server 10 is a management target (the ID received from the registration request source mail server 10 in the ID stored in advance as information of the management target mail server 10 is included) That it is).

Subsequently, in S402, it is determined whether or not the authentication is successful as a result of the authentication process.
If it is determined in S402 that the authentication is OK, the process proceeds to S403, and the server information of the mail server 10 of the registration request source is registered in the registration server database.

In step S404, registration OK information indicating that the server information is registered in the registration server database is transmitted to the mail server 10. Thereafter, the registration process is terminated.
On the other hand, if it is determined in S402 that the authentication is not OK, the process proceeds to S405, and error information indicating that the server information has not been registered in the registration server database is transmitted to the mail server 10. Thereafter, the registration process is terminated.

[3-5. Mail sending process]
Next, a mail transmission process executed by the CPU 32 of the authentication server 30 when a transmission request is received from the mail server 10 will be described with reference to the flowchart of FIG. The transmission request is made based on the process of S302 in the transmission request process (FIG. 10) described above.

  When starting the mail transmission process, the CPU 32 first performs the above-described challenge / response authentication process with the mail server (transmission-side mail server) 10 as the transmission request source in S501. Further, it is confirmed that the server information of the sending mail server 10 is registered in the registration server database.

  It should be noted that the authentication of the sending mail server 10 is basically an authentication OK even if the authentication result at the time of activation is authentication OK, but an illegal act (spam mail transmission, etc.) was performed after the activation. In such a case, authentication is not OK. That is, since the authentication server 30 knows the mail transmission status of each mail server 10, it is possible to detect an illegal action, and when an illegal action is found, the server of the mail server 10 Delete information from the registration server database.

Subsequently, in S502, it is determined whether or not authentication is OK as a result of the authentication process.
If it is determined in S502 that the authentication is OK, the process proceeds to S503, and the authentication OK authentication result is transmitted to the transmission side mail server 10.

  Subsequently, in S504, it is determined whether or not the transmission side mail server 10 can directly establish a session with the mail server (reception side mail server) 10 that is the transmission destination of the electronic mail. Note that the authentication server 30 includes information on whether or not a session to the mail server 10 can be established in the authentication process (IP address, UPnP support, presence / absence of a firewall, NAT or router port open state, etc.) Information (IP, e-mail address, etc.) for name resolution of the mail server 10 is received from the sending mail server 10. Then, based on the information on the sending mail server 10 and the similar information on the receiving mail server 10, it is determined whether or not a session can be established from the sending mail server 10 to the receiving mail server 10. For example, when the firewall setting of the destination mail server 10 is set to accept access from the transmission side mail server 10, or the port of the router connected to the LAN where the destination mail server 10 exists Is opened, and it is determined that a session can be established from the transmission side mail server 10 to the reception side mail server 10 when it is set to be accessible from the outside. Further, when the electronic mail to be transmitted by the transmission side mail server 10 is reserved transmission, information indicating that the transmission is reserved transmission and the reservation transmission time are received from the transmission side mail server 10.

  If it is determined in S504 that the sending mail server 10 can directly establish a session with the receiving mail server 10, the process proceeds to S505, and the determination result in S504 is sent to the sending mail server 10. Notice.

Subsequently, in S506, it is determined whether or not the electronic mail to be transmitted by the transmission side mail server 10 is a reserved transmission mail.
If it is determined in S506 that the mail is a reserved transmission mail, the process proceeds to S507, and it is determined whether an authentication request has been received from the transmission side mail server 10 at the transmission time designated by the reserved transmission mail. That is, in the case of reserved transmission mail, the transmission side mail server 10 is authenticated again after the designated transmission time has arrived.

If it is determined in S507 that an authentication request has been received from the sending mail server 10 at the designated transmission time, the process proceeds to S508.
On the other hand, if it is determined in S506 that the mail is not a reserved transmission mail, the process proceeds to S508 as it is.

  In step S508, the transmission side mail server 10 is notified of transmission permission. Thereafter, the mail transmission process is terminated. Thereby, the transmission side mail server 10 directly transmits the electronic mail to the reception side mail server 10.

  On the other hand, if it is determined in step S502 that the authentication is not OK, or if it is determined in step S507 that an authentication request has not been received from the transmission side mail server 10 at the transmission time, the process proceeds to step S509 and authentication rejection is transmitted to the transmission side mail server 10. To notify. Thereafter, the mail transmission process is terminated.

  If it is determined in S504 that the sending mail server 10 cannot directly establish a session with the receiving mail server 10, the process proceeds to S510, and the determination result in S504 is sent to the sending mail server 10. Notify them.

Subsequently, in S511, it is determined whether or not the e-mail to be transmitted by the transmission side mail server 10 is a reserved transmission mail.
If it is determined in S511 that it is a reserved transmission mail, the process proceeds to S512, and a notification process for notifying the transmission side mail server 10 and the reception side mail server 10 of the session time is performed. As a result, a session is established from the sending mail server 10 and the receiving mail server 10 at the notified session time. Thereafter, the process proceeds to S514. The specific contents of the notification process will be described later (FIG. 13).

  On the other hand, if it is determined in S511 that the mail is not a reserved transmission mail, the process proceeds to S513, and the transmission side mail server 10 is notified of the session time that matches the inquiry time from the reception side mail server 10. As a result, a session is established from the sending mail server 10 at a timing that matches the inquiry time from the receiving mail server 10. Thereafter, the process proceeds to S514.

In S514, it is determined whether or not a session is established from the sending mail server 10 at the session time.
If it is determined in S514 that a session is established from the sending mail server 10, the process proceeds to S515, and it is determined whether or not a session is established from the receiving mail server 10 at the session time.

  In S515, when it is determined that a session is established from the receiving mail server 10 (that is, when it becomes possible to relay an e-mail from the sending mail server 10 to the receiving mail server 10). , The process proceeds to S516, and a transmission permission notification is transmitted to the transmission side mail server 10. Thereby, an electronic mail is transmitted from the transmission side mail server 10.

  Subsequently, in S517, a process of transmitting the e-mail transmitted from the transmitting mail server 10 to the receiving mail server 10 (an e-mail relay process) is performed. Thereafter, the mail transmission process is terminated.

  On the other hand, if it is determined in S514 that a session is not established from the sending mail server 10, or if it is determined in S515 that a session is not established from the receiving mail server 10, the process proceeds to S518 and the first designated time It is determined whether or not a certain time has passed since.

  If it is determined in S518 that the fixed time has not elapsed since the first designated time, the process proceeds to S519 to notify the sending mail server 10 and the receiving mail server 10 of the new session time. After performing the notification process (FIG. 13), the process returns to S514. In other words, the session time is reset. As a result, a session is established from the sending mail server 10 and the receiving mail server 10 at the notified session time.

  On the other hand, if it is determined in S518 that the predetermined time has elapsed since the first designated time, the process proceeds to S520, and a notification process for notifying the transmission side mail server 10 and the reception side mail server 10 of an error. After performing (FIG. 13), this mail transmission process is complete | finished. That is, even if a certain time has elapsed from the first designated time (even if the session time is reset), a session is established from at least one of the sending mail server 10 and the receiving mail server 10 at the session time. If not, the mail transmission process is terminated.

[3-6. Notification processing]
Next, the notification process executed in S512, S519, and S520 in the above-described mail transmission process (FIG. 12) will be described with reference to the flowchart of FIG. In this notification process, “status” refers to the session time in the processes of S512 and S519, and error information in the process of S520.

When starting the notification process, the CPU 32 first determines whether the authentication server 30 is accessible to the receiving mail server 10 in S601.
If it is determined in S601 that the receiving mail server 10 is accessible, the process proceeds to S602, and the receiving mail server 10 is notified of the status. Thereafter, the process proceeds to S604.

  On the other hand, when it is determined in S601 that the receiving side mail server 10 is not accessible, the process proceeds to S603, and a status is notified to the receiving side mail server 10 at the time of inquiry from the receiving side mail server 10. Thereafter, the process proceeds to S604.

In S <b> 604, the authentication server 30 determines whether or not the sender mail server 10 is accessible.
If it is determined in S604 that the transmission side mail server 10 is accessible, the process proceeds to S605 to notify the transmission side mail server 10 of the status. Thereafter, the notification process is terminated.

  On the other hand, if it is determined in S604 that the transmission side mail server 10 is not accessible, the process proceeds to S606, and a status is notified to the transmission side mail server 10 when an inquiry is made from the transmission side mail server 10. Thereafter, the notification process is terminated.

[4. effect]
As described above, in the communication system of the present embodiment, the mail server 10 periodically communicates with the authentication server 30 (FIG. 9). Further, the mail server 10 requests the authentication server 30 to relay an email when transmitting an email to another mail server 10 (FIG. 10).

  On the other hand, the authentication server 30, when requested to relay an email from the mail server 10, communicates with the authentication server 30 by the requesting mail server (transmission side mail server) 10 and the mail server to which the email is sent. It adjusts so that communication with the said authentication server 30 by (receiving side mail server) 10 may be performed at the overlapping timing (S511-S513). Then, at the adjusted timing, the electronic mail transmitted from the transmission side mail server 10 is relayed to be transmitted to the reception side mail server 10 (S516, S517).

  According to such a communication system, an e-mail can be transmitted to the mail server 10 in which access from an external network is restricted by NAT or the like.

  In addition, if the e-mail requested to be relayed from the mail server 10 is not a reserved transmission mail (S511: NO), the authentication server 30 performs communication performed periodically by the receiving mail server 10 with respect to the authentication server 30. The session time according to the timing is notified to the sending mail server 10 (S513). For this reason, it is possible to relay the electronic mail from the transmission side mail server 10 to the reception side mail server 10 using the communication periodically performed by the reception side mail server 10 to the authentication server 30 as it is.

  On the other hand, if the e-mail requested to be relayed from the mail server 10 is a reserved transmission mail (S511: YES), the authentication server 30 performs the authentication at the timing when the receiving mail server 10 matches the transmission time designated by the reserved mail. It adjusts so that it may communicate with the server 30 (S512). For this reason, the electronic mail from the transmission side mail server 10 can be relayed to the reception side mail server 10 at the designated transmission time.

  Further, the authentication server 30, when communication is not performed from at least one of the transmission side mail server 10 and the reception side mail server 10 to the authentication server 30 at the adjusted timing (S514: NO, S515). : NO), readjustment is performed so that the communication to the authentication server 30 by the transmission side mail server 10 and the communication to the authentication server 30 by the reception side mail server 10 are performed at overlapping timing (S519). For this reason, when the e-mail cannot be relayed for some reason, the relay is tried again, and it is possible to prevent the e-mail from being transmitted for a temporary cause.

[5. Correspondence with Claims]
In the communication system of this embodiment, the mail server 10 corresponds to the server device, and the CPU 12 of the mail server 10 that executes the inquiry process (FIG. 9) corresponds to the periodic communication means, and the transmission request process (FIG. 10). The CPU 12 of the mail server 10 that executes “) corresponds to a mail transmission means.

  Further, the authentication server 30 corresponds to the relay device, and the CPU 32 of the authentication server 30 that executes the processes of S511 to S515 and S519 in the mail transmission process (FIG. 12) corresponds to the adjusting means, and performs the processes of S516 and S517. The CPU 32 of the authentication server 30 to execute corresponds to the relay unit.

[6. Other forms]
As mentioned above, although one Embodiment of this invention was described, it cannot be overemphasized that this invention can take a various form.

  For example, in the above embodiment, the authentication server 30 is exemplified as the relay device of the present invention. However, when the number of the mail servers 10 increases, the load on the authentication server 30 increases. May be performed. Specifically, for example, a specific mail server 10 that has a global IP address and access from an external network is allowed to function as a relay node, and the relay node has the same role as the authentication server 30 of the above embodiment. To fulfill. In this way, it is possible to maintain scalability against the increase in the number of mail servers 10 by adjusting the number of relay nodes. Further, when the transmission side mail server 10 or the reception side mail server 10 cannot access the relay node, the authentication server 30 is notified that the connection is impossible, and the authentication server 30 is provided with another relay node. It is also possible.

  Further, the ID and password of each mail server 10 stored in the registration server database may be stored in advance in each mail server 10 as in the above-described embodiment, or by the administrator of the mail server 10. It may be set in the mail server 10.

  Furthermore, on the condition that the authentication server 30 notifies the reception side mail server 10 or the transmission side mail server 10 of the session time in the processing of S512, S513, and S519 of FIG. It is preferable to instruct the stretched receiving mail server 10 or transmitting mail server 10 to wait for a predetermined time. In this way, even if there is a slight deviation between the time measured by the receiving side mail server 10 and the time measured by the transmitting side mail server 10, if the deviation is within the predetermined time, the authentication is performed. The server 30 can relay mail.

It is a block diagram which shows schematic structure of the communication system of embodiment. It is a block diagram which shows schematic structure of a mail server. It is a block diagram which shows schematic structure of an authentication server. It is a ladder chart of mail transmission / reception processing example (1). It is a ladder chart of the mail transmission / reception processing example (2). It is a ladder chart of the mail transmission / reception processing example (3). It is a ladder chart of the mail transmission / reception processing example (4). It is a flowchart of a registration request process. It is a flowchart of an inquiry process. It is a flowchart of a transmission request process. It is a flowchart of a registration process. It is a flowchart of a mail transmission process. It is a flowchart of a notification process.

  DESCRIPTION OF SYMBOLS 10 ... Mail server, 11 ... Control part, 12 ... CPU, 13 ... ROM, 14 ... RAM, 15 ... Sound input part, 16 ... Sound output part, 17 ... Communication part, 18 ... Operation part, 19 ... Display part, 20 ... Image reading unit, 21 ... Image printing unit, 22 ... Storage unit, 30 ... Authentication server, 31 ... Control unit, 32 ... CPU, 33 ... ROM, 34 ... RAM, 35 ... Communication unit, 36 ... Storage unit, 50 ... the Internet

Claims (8)

A plurality of server devices functioning as mail servers and a relay device that relays communication between the server devices are communication systems configured to be communicable,
The server device
Periodic communication means for periodically communicating with the relay device;
A mail transmitting means for requesting the relay device to relay an email when sending an email to another server device;
The relay device is
When the server device requests relaying of the e-mail, the communication to the relay device by the requesting server device and the communication to the relay device by the server device to which the e-mail is transmitted are performed at an overlapping timing. Adjusting means for adjusting to
Relaying means for relaying an e-mail transmitted from the requesting server apparatus so as to be transmitted to the destination server apparatus at a timing adjusted by the adjusting means. system. When the server device is requested to relay an email, the adjustment unit sets a transmission timing corresponding to a communication timing periodically performed by the transmission destination server device to the relay device. Notify the server device,
The communication system according to claim 1, wherein the mail transmission unit transmits an electronic mail to the relay apparatus at the transmission timing notified from the relay apparatus. The mail transmission means requests the relay device to relay an email at the transmission time when transmitting an email with a specified transmission time to another server device,
When the server device is requested to relay the e-mail at the transmission time, the adjustment device communicates with the relay device at a timing that matches the transmission time of the server device at the transmission destination. The communication system according to claim 1, wherein the communication system is adjusted as follows. The adjustment unit, when communication is not performed from at least one of the request source server device and the transmission destination server device to the relay device at the adjusted timing, the request source server device 4. The readjustment is performed so that the communication with the relay device by the server and the communication with the relay device by the destination server device are performed at overlapping timings. 5. The communication system according to 1. A plurality of server devices that function as mail servers and a relay device that relays communication between the server devices are information processing devices used as the server devices in a communication system configured to be communicable,
Periodic communication means for periodically communicating with the relay device;
A mail transmission means for requesting the relay device to relay an email when sending an email to another server device;
Equipped with a,
The mail transmission means is a timing adjusted by the relay device when the relay device requests relay of the electronic mail, and the server device communicates with the relay device and the destination of the electronic mail. in the timing of communication and overlap with respect to the relay device by the server apparatus, the information processing apparatus characterized that you send e-mail to the relay device. A plurality of server devices functioning as mail servers and a relay device that relays communication between the server devices are information processing devices used as the relay device in a communication system configured to be communicable,
When the server device requests relaying of the e-mail, the communication to the relay device by the requesting server device and the communication to the relay device by the server device to which the e-mail is transmitted are performed at an overlapping timing. Adjusting means for adjusting to
Relay means for relaying an e-mail transmitted from the requesting server apparatus to be transmitted to the destination server apparatus at a timing adjusted by the adjusting means;
An information processing apparatus comprising: A plurality of server devices functioning as mail servers and a relay device that relays communication between the server devices are programs for causing a computer to function as the server device in a communication system configured to be communicable,
Periodic communication means for periodically communicating with the relay device;
When sending an e-mail to another server device, the computer functions as a mail sending means for requesting the relay device to relay the e-mail ,
The mail transmission means is a timing adjusted by the relay device when the relay device requests relay of the electronic mail, and the server device communicates with the relay device and the destination of the electronic mail. in the timing of communication and overlap with respect to the relay device by the server apparatus, the program characterized that you send e-mail to the relay device. A plurality of server devices functioning as mail servers and a relay device that relays communication between the server devices are programs for causing a computer to function as the relay device in a communication system configured to be communicable,
When the server device requests relaying of the e-mail, the communication to the relay device by the requesting server device and the communication to the relay device by the server device to which the e-mail is transmitted are performed at an overlapping timing. Adjusting means for adjusting to
The computer is caused to function as a relay unit that relays an e-mail transmitted from the request source server device to be transmitted to the destination server device at a timing adjusted by the adjustment unit. program.

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