Mail relay apparatus

Abstract

To allow all received emails to be viewed without omission, while disabling clicks on link destination information such as URLs, enabling the recipient to safely and reliably determine for themselves whether the linked destination is useful.SOLUTION: A mail acquisition unit 132 acquires a target received email from a predetermined mail server in response to a reception request from a subordinate PC and records the acquired email as an original received email in an original mail storage unit 111. An imaging processing unit 113 converts the entire original received email stored in the original mail storage unit 111 into image data to form a received mail image, and provides the received mail image to the PC that transmitted the reception request.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a device for preventing e-mails from being directed to fraudulent sites or the like based on link information such as URLs (Uniform Resource Locators) included in the e-mails. [Background technology]

[0002] With the widespread use of information and communication devices such as personal computers (PCs), tablet PCs, and smartphones, email, which can be accessed through these devices, is widely used as both a personal communication tool and a business tool. However, anyone can send email to any recipient as long as they know the recipient's email address. This has led to a constant stream of spam, such as advertising emails with embedded links leading to various solicitations or product sales sites, and phishing emails with embedded links leading to fraudulent sites designed to steal credit card information.

[0003] To deal with such spam emails, for example, Patent Document 1, described below, discloses an invention relating to a system for preventing users from being redirected to fraudulent sites. In the invention disclosed in Patent Document 1, a fraudulent email determination unit determines whether a link contained in a received email addressed to a user is a link to a suspected fraudulent site. If it is determined to be a link to a suspected fraudulent site, a mail rewriting unit rewrites the link destination address to the address of an unauthorized access warning device. When a user opens the rewritten link, the unauthorized access warning device displays a warning message on the display screen of the terminal device. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-202046 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the case of the invention disclosed in Patent Document 1, as mentioned above, the fraudulent email determination unit determines whether a link contained in an incoming email is a link to a suspected fraudulent site. This determination is made by comparing the address of the sender of the incoming email with the address of the linked URL contained in the body of the incoming email. For this reason, it is conceivable that in some cases, an email may be determined to be fraudulent even though it is, or conversely, an email may be determined to be fraudulent even though it is not.

[0006] Furthermore, in the case of an incoming email containing link information to various solicitation or product sales sites, both the address of the sender of the incoming email and the address of the linked URL included in the body of the incoming email belong to the sender of the incoming email. For this reason, the link is determined not to be a link to a site suspected of fraud, and the invention disclosed in Patent Document 1 cannot prevent users from being directed to various solicitation or product sales sites.

[0007] Therefore, it is up to the recipient of the received email to decide whether link information such as a URL contained in the received email is useful to them, that is, whether it is okay to click on it and visit the site they are directed to. For this reason, the recipient of the received email must calmly decide whether the link information contained in the received email is useful to them. However, if a link information is contained in the received email, simply clicking on it by mistake can access the associated site, which is not desirable. It is desirable to prevent the recipient from immediately accessing the associated site even if they click on the link information by mistake.

[0008] In view of the above, the object of this invention is to enable a recipient to view all received emails without omission, to disable clicking on link destination information such as URLs, and to enable the recipient to safely and reliably determine for themselves whether the link destination is useful or not. [Means for solving the problem]

[0009] In order to solve the above problem, the mail relay device of the invention described in claim 1 comprises: a mail acquisition means for acquiring a target received mail from a predetermined mail server device in response to a request for receiving the received mail from a subordinate terminal device, and recording the acquired received mail as an original in a mail original storage means; an image processing means for forming a received mail image by converting the entire received mail original stored in the mail original storage means into image data, and providing the received mail image to the terminal device that is the sender of the reception request; The present invention is characterized by comprising:

[0010] According to the mail relay device of the invention described in claim 1, the mail acquisition means acquires the target received mail from a specified mail server device in response to a reception request from a subordinate terminal device, and records this as the received mail original in the mail original storage means. The imaging processing means converts the entire received mail original stored in the mail original storage means into image data, thereby forming a received mail image, which is provided to the terminal device that sent the reception request. This allows the user of the terminal device to view the entire received mail through the received mail image, and link information such as URLs becomes mere display information and cannot be clicked on. Therefore, there is no need to worry about accessing a site associated with link information contained in the received mail due to an erroneous operation. [Effects of the Invention]

[0011] According to this invention, it is possible to view all received emails without omission, and link destination information such as URLs is made unclickable, allowing the recipient to safely and reliably determine for themselves whether the link destination is useful or not. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram illustrating an example of a configuration of a network system according to an embodiment. [Figure 2] 1 is a block diagram illustrating an example of the configuration of a UTM device to which an embodiment of a mail relay device according to the present invention is applied. [Figure 3] 10A and 10B are diagrams illustrating an example of an original received email and an example of an image of the received email. [Figure 4] FIG. 10 is a sequence diagram illustrating the operation of the network system according to the embodiment when webmail is used. [Figure 5] This is a sequence diagram continuing from FIG. [Figure 6] FIG. 10 is a sequence diagram illustrating the operation of the network system according to the embodiment when general email is used using a mailer. [Figure 7] This is a sequence diagram continuing from FIG. DETAILED DESCRIPTION OF THE INVENTION

[0013] An embodiment of a device according to the present invention will be described below with reference to the drawings. In the following embodiment, the device according to the present invention will be described as being applied to a UTM (Unified Threat Management) device. The UTM device 1 integrates multiple different security functions into a single piece of hardware to centralize security management related to networks, etc. In other words, the UTM device efficiently and comprehensively protects a LAN (Local Area Network) system established within a company from threats such as computer viruses and hacking. In this specification, a WAN (Wide Area Network) refers to a network that is wider than a LAN or a MAN (Metropolitan Area Network), and is synonymous with the Internet. The LAN will be described as an example established within a specific company.

[0014] [Network system configuration example] FIG. 1 is a diagram illustrating an example of the configuration of a network system according to an embodiment. In FIG. 1, the Internet 4 shown in the center represents a computer network interconnected using Internet Protocol Suite technology, also referred to as a WAN. As shown in FIG. 1, a UTM device 1 is connected to the Internet 4. Multiple PCs 3(1), 3(2), 3(3), ... are connected to the UTM device 1 via a LAN 2, thereby constituting a LAN system. As shown in FIG. 1, the UTM device 1 of this embodiment also functions as a relay device that monitors, controls, and manages communications between the Internet (WAN) 4 and the LAN 2 and communications between PCs connected to the LAN 2.

[0015] As is well known, each of PCs 3(1), 3(2), 3(3), ... is an information processing device that can execute various application software (hereinafter referred to as "apps") to process information. For example, a word processing app can be executed to create documents, or a spreadsheet app can be executed to create charts and graphs. Each of PCs 3(1), 3(2), 3(3), ... also has a communication function. Therefore, each of PCs 3(1), 3(2), 3(3), ... can use a browser (browsing software) to view web pages stored on various web server devices (not shown) located on the Internet 4. Of course, each of PCs 3(1), 3(2), 3(3), ... can also send and receive e-mail.

[0016] The Internet 4 is also connected to a mail server 5, a PC 6(1), and a smartphone 7(1) via a base station BS(1). The mail server 5 is used by users of PCs 3(1), 3(2), 3(3), etc., under the control of the UTM device 1, to send and receive emails. The mail server 5 has an inbox that stores received emails addressed to users of PCs 3(1), 3(2), 3(3), etc., under the control of the UTM device 1, and an outbox that stores sent emails from PCs 3(1), 3(2), 3(3), etc., under the control of the UTM device 1. Note that FIG. 1 shows only one of the mail server 5, PC 6(1), base station BS(1), and smartphone 7(1). However, these are shown as representative examples; in reality, many mail servers, PCs, base stations, and smartphones are connected to the Internet 4 and communicate via the Internet.

[0017] In the network system of this embodiment, the users of PCs 3(1), 3(2), 3(3), ... subordinate to the UTM device 1 receive emails (incoming emails) addressed to them via the UTM device 1. In this case, the UTM device 1 has a conventional function of blocking emails with unwanted advertisements or viruses attached, but it does more than that. The UTM device 1 converts all incoming emails to its subordinate PCs 3(1), 3(2), 3(3), ... into images to create received email images, and makes it impossible to click on link information to sites such as URLs, before providing the images to PCs 3(1), 3(2), 3(3), ....

[0018] This means that even if you accidentally click on a link while viewing an image of a received email, the link will not function because it is an image, and you will not be redirected to the linked (associated) site. Therefore, if you carefully check the image of the received email and want to click on the link to view the associated site, you can request and receive the email (original received email) before it is converted into an image. Since the link information in the original received email is functional, you can view the site associated with the link by clicking on it.

[0019] In this way, the original received email mainly refers to the received email itself before it is imaged. However, it is considered that the original received email may have some information added, deleted, or changed, for example, when it is received or stored in the original email storage unit 111. For this reason, in this specification, even if some information has been added, deleted, or changed to the received email, it is considered to be the original received email as long as the added link information to the site, such as a URL, is still valid.

[0020] Furthermore, after carefully checking the original received email, if the user wishes to send a reply to the sender of the original received email, the user requests the UTM device 1 to send a reply. This allows the user to send (reply) information such as the reply message entered as a reply to the original received email to the sender of the original received email. Furthermore, after carefully checking the image of the received email, if the user determines that the original received email corresponding to the image of the received email is unnecessary, the user can request the deletion of the original received email, which will be deleted from the storage unit of the UTM device 1 and rendered unusable.

[0021] Note that functions such as imaging of received emails, providing the original received email before imaging, replying to the original received email before imaging, and deleting the original received email before imaging are mainly realized by the UTM device 1. PCs 3(1), 3(2), 3(3), ... under the control of the UTM device 1 remain the same as before and do not require any changes. The configuration of the UTM device 1 and the operation of the network system of this embodiment centered around the UTM device 1 will be described below.

[0022] [UTM device 1 configuration] FIG. 2 is a block diagram illustrating an example of the configuration of a UTM device to which an embodiment of a mail relay device according to the present invention is applied. In FIG. 2, connection terminal 101T constitutes a connection terminal with the Internet (WAN) 4. WAN I / F (Interface) 101 is a part that processes communications via the Internet 4. WAN I / F 101 converts signals addressed to the device itself that are transmitted via the Internet 4 into signals in a format that can be processed by the device itself and then imports these signals. WAN I / F 101 also converts signals to be transmitted from the device itself into signals in a format for transmission and sends them to the Internet 4 to be transmitted to the other party. Therefore, when communicating with a party connected to the Internet 4, the communication is performed via connection terminal 101T and WAN I / F 101.

[0023] Although not shown, the control unit 102 is a microprocessor configured with a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), non-volatile memory, etc., and controls each part of the UTM device 1. The storage device 103 is a device unit consisting of a recording medium such as an HDD (Hard Disk Drive) or SSD (Solid State Drive) and its driver, and records, reads, modifies, deletes, etc., various data on the recording medium. In addition to storing and holding necessary data and programs, the storage device 103 is also used as a working area for temporarily storing intermediate data generated in various processes.

[0024] The connection terminal 104T constitutes the connection terminal with the LAN2. The LANI / F (Interface) 104 is a part that performs communication processing via the LAN2. That is, the LANI / F 104 converts signals sent to the device itself via the LAN2 into signals in a format that can be processed by the device itself and then imports these signals. The LANI / F 104 also converts signals to be sent from the device itself into signals in a format for transmission and sends them to the LAN2 to be transmitted to the other party. Therefore, when communication with the PC3 connected to the LAN2 is performed, it is performed via the connection terminal 104T and the LANI / F 104.

[0025] The original email storage unit 111 and the email image storage unit 112 are formed in a storage device that includes a recording medium, such as an HDD or SSD, and its driver. The original email storage unit 111 and the email image storage unit 112 may be formed in different storage devices, or may be formed in different storage areas in the same storage device. In this embodiment, the original email storage unit 111 and the email image storage unit 112 are formed in different storage devices. The original email storage unit 111 stores and holds original received emails received from the email server 5 via the Internet 4. The email image storage unit 112 stores and holds received email images that are created by imaging the received original received emails.

[0026] 3A and 3B are diagrams illustrating examples of original received emails and examples of images of received emails. The original received emails stored in the original email storage unit 111 are, as shown in FIG. 3A, the emails themselves addressed to the user of PC 3. For this reason, when a URL that is link information to a product information site or a URL that is link information to an inquiry site that exists in the original received email is clicked, a browser is launched and the user is taken to the associated site. In FIG. 3A, the underlined parts are valid (active) link information that executes the function of taking the user to the associated site when clicked.

[0027] In contrast, the received email image stored in email image storage unit 112 is an image of the entire email (original received email) addressed to the user of PC3, which is treated as image data, as shown in Figure 3(B). Therefore, the link information to the product information site or the inquiry site that exists in the received email image only serves as display information (image information), and clicking on the display portion does not transition to the product information site or the inquiry site. Therefore, the display of the link information in the received email image is simply display information and no longer functions as link information.

[0028] The received email image shown in Fig. 3(B) has three operation buttons for receiving instruction input from the user of the PC3 that provides the received email image: an original button B1, a reply button B2, and a delete button B3. The original button (first operation indicator) B1 is for the PC3 to acquire the original received email, and the reply button (second operation indicator) B2 is for sending a reply email to the original received email from the PC3. The delete button (third operation indicator) B3 is for deleting the original email stored in the original email storage unit 111 from the PC3, making it unavailable. More specific usage of these operation buttons will be described later.

[0029] The security function unit 120 realizes the function of centralizing security management. Specifically, although not shown, the security function unit 120 is configured to include, for example, a P2P countermeasure unit, an HP access control unit, an anti-virus unit, an anti-mail unit, an IPS / IDS unit, and a firewall unit. In other words, the security function unit 120 realizes the function of prohibiting P2P connections with parties that have not implemented security measures or with malicious parties (function as a P2P countermeasure unit). Note that "P2P" stands for "Peer to Peer," meaning that equal parties communicate directly with each other via the Internet.

[0030] Furthermore, the security function unit 120 realizes a function of prohibiting access to homepages that fall into a desired category by selecting the desired homepage category in advance (a function as a homepage access control unit). The security function unit 120 also verifies (virus checks) responses to web pages (a function as an anti-virus unit). More specifically, the security function unit 120 realizes a function of monitoring communications when browsing web pages and verifying (checking) whether images to be viewed or files to be downloaded contain viruses. The security function unit 120 also realizes a function of blocking received e-mails that contain unwanted advertisements or viruses (a function as an e-mail anti-virus unit).

[0031] The security function unit 120 also functions to prevent inappropriate intrusions and notify users of inappropriate intrusions (functioning as an IPS / IDS unit). Here, IPS is an abbreviation for Intrusion Prevention System, and IDS is an abbreviation for Intrusion Detection System. The security function unit 120 can defend against attacks by so-called malware such as worms and Trojan horses. The security function unit 120 also determines whether to supply data to LAN2 based on the data communication status, the software used, etc., and realizes a function to protect the system from attacks and unauthorized access from external networks (functioning as a firewall unit).

[0032] The mail safety unit 130 realizes a function to secure the parts that are not sufficient just by blocking unwanted advertisements and e-mails with virus attachments as the mail countermeasure unit of the security function unit 120. That is, it creates an image of the original received e-mail to form a received e-mail image, invalidates link information, and prevents a transition to the associated site even if the link information display is accidentally clicked. This allows the user to determine whether the link information in the received e-mail is useful or not, and then obtain and use the original e-mail, delete it from the original e-mail storage unit 111 to make it unusable, or send a reply to the original e-mail.

[0033] The following describes each unit that makes up the mail safety unit 130. In response to a request from PC3, the login processing unit 131 executes a login process to the mail server 5 used by the user of PC3, connects PC3 to the mail server 5, and performs a process to make the mail server 5 available for use. The mail acquisition unit 132 acquires the original of the desired received mail from the mail server 5 logged in through PC3, and performs a process to record this in the original mail storage unit 111.

[0034] The imaging processing unit 133 images the original received email recorded in the original email storage unit 111 to form an image of the received email, and stores this in the email image storage unit 112, while also providing it to the PC 3 that has requested the acquisition of the received email. As explained with reference to Fig. 3(B), the image of the received email formed by the imaging processing unit 133 is provided with an original button B1, a reply button B2, and a delete button B3, and also includes processing programs that function when these display buttons are selected and operated by the user.

[0035] That is, when the original button B1 is selected, a request to acquire the original received email from the PC 3 is formed and provided to the UTM device 1. When the reply button B2 is selected, a request to create and send a reply email is formed from the PC 3 and provided to the UTM device 1. When the delete button B3 is selected, a request to delete the desired original received email is formed from the PC 3 and provided to the UTM device 1.

[0036] Also, in the above description, the imaging processing unit 133 images the original received email to form a received email image, records this in the email image storage unit 112, and provides it to the requesting PC. However, this is not limited to this. For example, it is also possible to configure the imaging processing unit 133 to perform the process of imaging the original received email to form a received email image and record this in the email image storage unit 112, and to provide a separate email image providing unit that provides the received email image to the requesting PC 3.

[0037] The original email providing unit 134 functions when the original email button B1 attached to the received email image is pressed on a PC 3 logged in to the mail server 5, and a corresponding request is sent from the PC 3 to the UTM device 1. The original email providing unit 134 reads out the original email corresponding to the received email image provided to the requesting PC 3 from the original email storage unit 111, and provides it to the requesting PC 3 (the PC 3 on which the original button B1 was pressed). The original email deleting unit 135 functions when the delete button B3 attached to the received email image is pressed on a PC 3 logged in to the mail server 5, and a corresponding request is sent from the PC 3 to the UTM device 1. The original email deleting unit 135 deletes the original email corresponding to the received email image provided to the requesting PC 3 from the original email storage unit 111, making it unavailable.

[0038] The email reply function unit 136 functions when the reply button B2 attached to the received email image is pressed on the PC 3 logged in to the email server 5, and a corresponding request is sent from the PC 3 to the UTM device 1. The email reply function unit 136 accepts input of reply information for the original received email corresponding to the received email image provided to the requesting PC 3, creates a reply email, and performs processing to send this to the sender of the original received email.

[0039] In this way, in the UTM device 1 of this embodiment, when the original received email is acquired by the function of the email safety unit 130, the original received email is imaged to form an image of the received email, which is then provided to the requesting PC 3. In this way, what is provided to PC 3 is not the original received email (normally received email), but the image of the received email. Therefore, even if the user accidentally clicks on the displayed link information, the user will not be redirected to the associated site. Therefore, the user of PC 3 can take their time to calmly determine whether the link information included in the original received email is useful to them.

[0040] This allows the PC 3 to identify the user based on the received email image, and if the corresponding original received email is needed, the PC 3 can acquire and use that original received email. Also, if the corresponding original received email is no longer needed, the original received email can be deleted from the original email storage unit 111 to make it unusable. Also, a reply email to the corresponding original received email can be created and sent to the sender of the original received email.

[0041] [Operation of the network system according to the embodiment] Next, we will explain the operation of using email in a network system of this embodiment formed using the UTM device 1 to which one embodiment of the email relay device of this invention is provided. When using email, there are cases where email is created, viewed, sent, received, etc. on a browser, which is software for viewing web pages, and cases where email is created, viewed, sent, received, etc. using a mailer, which is software dedicated to email. In this specification, the former, which uses a browser, will be referred to as using webmail, and the latter, which uses a mailer, will be referred to as using general email.

[0042] The following explanation will be divided into two cases: when using webmail and when using general email. However, apart from slight differences in how the functional parts of the UTM device 1 are used, the UTM device 1 can basically process both cases in the same way. In other words, the email safety unit 130 of the UTM device 1 can be broadly divided into functions as an HTTP (Hyper Text Transfer Protocol) server unit, a conversion unit, a mail server unit, and a mail client unit.

[0043] The HTTP server unit is a functional unit that interprets URLs and HTTP and provides a mail service. The conversion unit is a functional unit that forms a received mail image by performing imaging processing on the original received mail. The mail server unit simply constitutes a connection processing functional unit with a client device (PC3 in this embodiment), relays information from PC3 to the mail client unit, and provides information from the mail client unit to PC3. The mail client unit constitutes a connection processing functional unit with a server device (mail server 5 in this embodiment) on the Internet 4, relays information from mail server 5 to the mail server unit, and provides information from the mail server unit to mail server 5.

[0044] Therefore, information from PC3 to mail server 5 on the Internet 4 is transmitted to mail server 5 via the mail client unit from the mail server unit. Also, information from mail server 5 on the Internet 4 to PC3 is transmitted to PC3 via the mail server unit from the mail client unit. Hereinafter, the operation of the network system of this embodiment will be specifically described.

[0045] <In the case of using webmail> FIG. 4 and FIG. 5 are sequence diagrams for explaining the operation of the network system of the embodiment when using webmail. In FIG. 4 and FIG. 5, the mail security unit 130 of the UTM device 1 is shown as having the functions of the HTTP server unit, the conversion unit, the mail server unit, and the mail client unit. As shown in the upper left part of FIG. 4, PC3 receives an operation input from a user who wants to view a received mail, first starts a browser, and executes a login process for connecting to a target webmail service through the started browser (step S1). In step S1, PC3 receives an input of an account and a password on the login screen of the webmail service and forms a login request.

[0046] The login request formed in step S1 is sent from PC3 to the UTM device 1 via LAN2 (step S2). The login request from PC3 is accepted by the HTTP server unit of the UTM device 1, where it is interpreted and provided to the mail server unit (step S3). The mail server unit passes the login request from the HTTP server unit to the mail client unit (step S4), and the mail client unit performs processing to send the login request from the mail server unit to the mail server 5 (step S5). The mail server 5 performs authentication processing using the account and password included in the received login request. If authentication is successful, the mail server 5 forms a success notification indicating that the login was successful along with the mail list, and returns this to the UTM device 1 (step S6).

[0047] The success notification from the mail server 5 is received by the mail client unit of the UTM device 1 and handed over to the mail server unit (step S7). The mail server unit provides the success notification from the mail client unit to the HTTP server unit (step S8). The success notification includes a mail list, and the HTTP server unit interprets the success notification, extracts the mail list, and provides it to the PC 3 that sent the login request (step S9).

[0048] In this way, the processing mainly from step S3 to step S9, which accepts a login request from PC3, logs in to the mail server 5, receives a mail list, and provides it to PC3, is performed by the login processing unit 131 of the UTM device 1. If the login authentication is not successful in the mail server 5, a login failure notice is sent from the mail server 5 to PC3 via the UTM device 1 in steps S6 to S9.

[0049] Upon receiving the mail list in step S9, PC3 displays the mail list on its display unit and accepts the designation of e-mails to be received (mail designation) (step S10). Based on the mail designation accepted in step S10, PC3 forms a display request for received mails including specific information of the designated received mails, and transmits the request to UTM device 1 via LAN2 (step S11).

[0050] The display request from PC3 is accepted by the HTTP server unit of the UTM device 1, where it is interpreted and provided to the mail server unit (step S12). The mail server unit passes the request to display the received mail from the HTTP server unit to the mail client unit (step S13). The mail client unit performs processing to send the display request from the mail server unit to the mail server 5 (step S14). The mail server 5, which has accepted the request to display the received mail, identifies the email (original received mail) addressed to the user of PC3 that made the request based on the specific information of the target email included in the display request, and returns this to the UTM device 1 (step S15). The original received mail from the mail server 5 is accepted by the mail client unit of the UTM device 1, which passes it on to the mail server unit and records it in the original mail storage unit 111 (step S16).

[0051] In this way, the process of accepting a display request from the PC 3, requesting the mail server 5 to provide the original received mail, acquiring the original received mail, and recording it in the original mail storage unit 111 is performed by the mail acquisition unit 132 of the UTM device 1. In other words, the process mainly from step S12 to step S16 is performed by the mail acquisition unit 132 of the UTM device 1.

[0052] Thereafter, the mail server unit of the UTM device 1 supplies the original received mail from the mail server 5 to the conversion unit (step S17), and the conversion unit performs imaging processing on the entire original received mail (step S18) to form a received mail image. The received mail image formed in step S18 is image data expressed in an image format such as JPEG format, PNG format, GIF format, TIFF format, or bitmap format. The received mail image formed by the conversion unit is recorded in the mail image storage unit 112 and is also supplied to the HTTP server unit (step S19). The HTTP server unit converts the received mail image from the conversion unit into a format to be provided to PC 3, and provides it to PC 3 that has requested display (step S20).

[0053] In this way, the process of converting the original received email obtained from the mail server 5 into a received email image, recording it in the email image storage unit 112, and providing it to the requesting PC 3 is performed by the imaging processing unit 133 of the UTM device 1. In other words, the processes from step S17 to step S20 are mainly performed by the imaging processing unit of the UTM device 1.

[0054] In this way, the PC 3 that has made the request to display the email is not provided with the original received email (normally received email), but rather with an image of the received email that has been created by imaging the original received email. As a result, the PC 3 that has made the request to display displays the image of the received email provided by the UTM device 1 on its display unit (step S21), and provides it to the user of the PC 3.

[0055] In this case, the link information such as the URL contained in the original received email becomes merely display information, and even if you accidentally click on that part, you will not be directed to the site associated with that link information. Therefore, the user can calmly and slowly check the entire image of the received email and decide whether the link information contained in the original received email corresponding to that image is useful to them.

[0056] When the received email image is displayed on the display unit of the PC 3 by the process of step S21 in FIG. 4, the user checks the received email image and determines whether or not the corresponding original received email is required and whether or not a reply to the original received email is required. The operations performed in response to these determinations are shown in FIG. 5. First, the operations performed when the user checks the received email image displayed on the display unit of the PC 3 and determines that the corresponding original received email is required will be described. In this case, the user selects the original button B1 of the received email image displayed on the display unit of the PC 3, as described with reference to FIG. 3(B). In this case, the processing in the email safing unit 130 of the UTM device 1 differs slightly depending on whether the original received email is obtained and used using a browser or a mailer.

[0057] First, we will explain the case where the original of a received email is obtained and used using a browser. Assume that the user of PC3 selects the original button B1 of the received email image (FIG. 3(B)) displayed on the display unit of PC3 in step S21 of FIG. 4. In this case, a program associated with the selected original button B1 is executed in the browser running on PC3, and a request to display the original is formed and sent to UTM device 1 via LAN 2 (step S22). The request to display the original includes information that identifies the original of the received email, and is interpreted by the HTTP server unit of UTM device 1, and its contents are grasped.

[0058] Based on the grasped content, the HTTP server unit of the UTM device 1 reads the desired original received email from the original email storage unit 111 and returns it to the requesting PC 3 (step S23). As a result, the original received email is provided to PC 3, and the original received email can be displayed and used on the browser. Therefore, the link information of the displayed original received email is clickable (selectable), so by clicking it, the associated site can be accessed and viewed.

[0059] Next, we will explain the case where the original of a received email is obtained and used using a mailer. Assume that the original button B1 of the received email image (FIG. 3(B)) displayed on the display unit of PC3 in step S21 of FIG. 4 is selected by the user of PC3. In this case, PC3 forms a request to receive the original and sends it to the UTM device 1 via LAN2 (step S24). The request includes information that identifies the original of the received email, and the HTTP server unit of UTM device 1 interprets this and supplies it to the mail server unit (step S25).

[0060] The mail server unit understands the contents of the interpreted original document reception request, and based on the understood contents, reads the desired received original document from the mail original document storage unit 111 and returns it to the requesting PC 3 (step S26). As a result, the received original document is provided to PC 3, and the received original document can be displayed on the display unit of PC 3 via the mailer and used. Therefore, the link information of the displayed received original document is clickable (selectable), and by clicking on it, the associated site can be accessed and viewed.

[0061] In this way, the process of accepting an original document reception request from PC3, obtaining the corresponding received email original, and providing it to the requesting PC3 is a process performed by the email original document providing unit 134 of the UTM device 1. In other words, the process of accepting an original document reception request provided mainly in the process of step S22 and providing the received email original in step S23 is a process performed by the email original document providing unit 134 of the UTM device 1. Alternatively, the process of accepting the original document reception request sent in step S24 and then executing steps S25 to S26 is a process performed by the email original document providing unit 134 of the UTM device 1.

[0062] Next, we will explain the operation when a user checks the received email image displayed on the display unit of PC3 and determines that the corresponding original received email is unnecessary. Assume that the user of PC3 selects the delete button B3 of the received email image (FIG. 3(B)) displayed on the display unit of PC3 in step S21 of FIG. 4. In this case, a program associated with the selected delete button B3 is executed in the browser running on PC3, and a request to delete the original is formed and sent to the UTM device 1 via LAN2 (step S27).

[0063] The original document deletion request includes information that identifies the received original email, and the HTTP server unit of the UTM device 1 interprets this and supplies the interpreted original document deletion request to the mail server unit (step S28). The mail server unit understands the content of the original document deletion request and executes processing to delete the target received original email from the original email storage unit 111. As a result, the target received original email is deleted from the original email storage unit 111 and becomes unusable. In this way, the processing of accepting the original document deletion request from the PC 3 and deleting the corresponding received original email stored in the original email storage unit 111 is processing performed by the original email deletion unit 135 of the UTM device 1. In other words, the processing of steps S27 to S28 is mainly processing performed by the original email deletion unit 135 of the UTM device 1.

[0064] Next, we will explain the operation when a user checks the received email image displayed on the display unit of PC3 and determines that a reply is necessary to the corresponding original received email. Assume that the user of PC3 selects the reply button B2 of the received email image (FIG. 3(B)) displayed on the display unit of PC3 in step S21 of FIG. 4. In this case, a program associated with the selected reply button B2 is executed in the browser running on PC3, and a reply request is formed and sent to UTM device 1 via LAN2 (step S29).

[0065] The reply request includes information identifying the original received email, and the HTTP server unit of the UTM device 1 interprets this and provides an input form for the reply email to the requesting PC 3 (step S30). Upon receiving the input form, PC 3 displays it on its display unit and accepts the user's input operation for the reply email (step S31). PC 3 then creates a reply sending request including the contents of the entered reply email and sends this to the UTM device 1 (step S32).

[0066] In the UTM device 1, the HTTP server unit functions to interpret the reply transmission request from the PC 3 and supply the interpreted reply transmission request to the mail server unit (step S33). The mail server unit understands the contents of the reply transmission request, creates a reply text (reply email), and supplies this to the mail client unit (step S34). The mail client unit prepares the reply text from the mail server unit into a reply email to be sent, and sends a reply transmission request including the reply email to the mail server 5 (step S35). As a result, the reply email included in the reply transmission request is sent via the mail server 5 to the mail server of the sender of the original received email, so that the sender can receive and view it.

[0067] In this way, the process of forming a reply email to the sender of the original received email in response to a reply request from PC 3 and sending this to the sender of the original received email is performed by the email reply function unit 136 of the UTM device 1. In other words, the processes of steps S29 to S35 are mainly performed by the email reply function unit 136 of the UTM device 1.

[0068] <When using general email> 6 and 7 are sequence diagrams illustrating the operation of a network system according to an embodiment when using general email using a mailer. In FIGS. 6 and 7, the mail safety unit 130 of the UTM device 1 is shown as having the functions of an HTTP server, a converter, a mail server, and a mail client. The PC 3 accepts an operation input from a user who wishes to view email addressed to the user, and first activates the mailer (step S41). Next, the mailer's functions are used to create a login request using a registered account and password, and the request is sent to the UTM device 1 via LAN 2 (step S42).

[0069] The login request from PC3 is accepted through the mail server unit of the UTM device 1, and the mail server unit transfers the login request from PC3 to the mail client unit (step S43). The mail client unit accepts the login request from the mail server unit and performs processing to send it to the mail server 5 (step S44). The mail server 5, which has accepted the login request, performs authentication processing using the account and password included in the login request. If authentication is successful, the mail server 5 forms a login success notice notifying that the login has been successful and returns this to the UTM device 1 (step S45). The login success notice from the mail server 5 is accepted by the mail client unit of the UTM device 1 and transferred to the mail server unit (step S46). The success notice is provided from the mail server unit to PC3, which has made the login request, via LAN 2 (step S47). This connects PC3, which has made the login request, to the mail server 5.

[0070] In this way, the processing from accepting a login request from PC3, logging in to the mail server 5, accepting a login success notification from the mail server 5, and notifying PC3 that made the request is performed by the login processing unit 131 of the UTM device 1. In other words, the processing from steps S43 to S47 is mainly performed by the login processing unit 131 of the UTM device 1. If the login authentication is not successful in the mail server 5, a login failure notification is sent from the mail server 5 to PC3 via the UTM device 1 in steps S45 to S47.

[0071] If login to the mail server 5 is successful, the mailer running on PC3 functions, creates a mail reception request, and sends it to the UTM device 1 via LAN 2 (step S48). The mail reception request is acquired by the mail server unit of the UTM device 1 and handed over to the mail client unit (step S49). The mail client unit accepts the mail reception request from the mail server unit and performs processing to send it to the mail server 5 (step S50). Having accepted the mail reception request, the mail server 5 extracts the email (original received mail) addressed to the user of PC3 that made the request, and returns this to the UTM device 1 (step S51). The original received mail returned in step S51 is accepted by the mail client unit and recorded in the original mail storage unit 111.

[0072] In this way, the processing performed by the mail acquisition unit 132 of the UTM device 1 is to accept a mail reception request from the PC 3, send it to the mail server 5, receive the original received mail from the mail server 5, and record it in the original mail storage unit 111. In other words, the processing performed by the mail acquisition unit 132 of the UTM device 1 mainly consists of steps S49 to S50, the processing for receiving the original received mail from the mail server 5, and the processing for recording the received original received mail in the original mail storage unit 111, although this is not shown.

[0073] Thereafter, the original received email accepted by the email client unit of the UTM device 1 is supplied to the conversion unit (step S52), where it is converted into an image to form an image of the received email (step S53). The received email image formed in step S53 is image data expressed in an image format such as JPEG, PNG, GIF, TIFF, or bitmap. The formed received email image is recorded in the email image storage unit 112 and is also supplied to the email server unit (step S54). The email server unit performs processing to transmit the received email image formed by the conversion unit to the requesting PC 3 via LAN 2 (step S55).

[0074] In this way, the processing of imaging the original email received from the email client unit to form an image of the received email, recording this in the email image storage unit 112, and providing it to the requesting PC 3 via the email server unit is performed by the imaging processing unit of the UTM device 1. In other words, the processing from step S52 to step S55 is mainly performed by the imaging processing unit 133 of the UTM device 1.

[0075] In this way, the PC 3 that has made the request to display the email is not provided with the original received email (normally received email), but rather with an image of the received email that has been created by imaging the original received email. As a result, the PC 3 that has made the request to display displays the image of the received email provided by the UTM device 1 on its display unit (step S56), and provides it to the user of the PC 3.

[0076] In this case, the link information such as the URL contained in the original received email is merely display information, so even if you accidentally click on that part, you will not be directed to the site associated with the link information. Therefore, the user can calmly and slowly check the entire image of the received email and decide whether the link information contained in the original received email corresponding to the received email image is useful to them.

[0077] When the received email image is displayed on the display unit of the PC 3 by the process of step S56 in FIG. 6, the user checks the received email image and determines whether or not the corresponding original received email is required and whether or not a reply to the original received email is required. The operations performed in response to these determinations are shown in FIG. 7. First, the operations performed when the user checks the received email image displayed on the display unit of the PC 3 and determines that the corresponding original received email is required will be described. In this case, the user selects the original button B1 of the received email image displayed on the display unit of the PC 3, as described with reference to FIG. 3(B). In this case, the processing in the email safing unit 130 of the UTM device 1 differs slightly depending on whether the original received email is obtained and used using a browser or a mailer.

[0078] First, we will explain the case where the original of a received email is obtained and used using a browser. Assume that the original button B1 of the received email image (FIG. 3(B)) displayed on the display unit of PC3 in step S56 of FIG. 6 is selected by the user of PC3. In this case, a browser is launched on PC3, and a program associated with the selected original button B1 is executed in the browser, forming a request to receive the original and sending it to UTM device 1 via LAN2 (step S57). The request to receive the original includes information that identifies the original of the received email, and is interpreted by the HTTP server unit of UTM device 1, and its contents are grasped.

[0079] Based on the grasped contents, the HTTP server reads the desired original received email from the original email storage unit 111 and returns it to the requesting PC 3 (step S58). As a result, the original received email is provided to PC 3, and the original received email can be displayed and used on the browser. In other words, the link information of the displayed original received email is clickable (selectable), so by clicking it, the associated site can be accessed and viewed.

[0080] Next, we will explain the case where the original of a received email is obtained and used using a mailer. Assume that the user of PC3 selects the original button B1 of the received email image (FIG. 3(B)) displayed on the display unit of PC3 in step S56 of FIG. 6. In this case, in step S41 of FIG. 6, the mailer already running on PC3 creates a request to receive the original and sends it to UTM device 1 via LAN 2 (step S59). The request includes information that identifies the original of the received email, and is accepted and interpreted by the HTTP server unit of UTM device 1, which then provides it to the mail server unit (step S60).

[0081] The mail server unit understands the contents of the original document reception request from the HTTP server unit, and based on the understood contents, reads the desired original received mail from the original mail storage unit 111 and returns it to the requesting PC 3 (step S61). As a result, the original received mail is provided to PC 3, and the original received mail can be displayed on the display unit of PC 3 via the mailer for use. In other words, the link information of the displayed original received mail is clickable (selectable), so by clicking it, the associated site can be accessed and viewed.

[0082] In this way, the process of accepting an original document reception request from PC3, obtaining the corresponding received original email document, and providing it to the requesting PC3 is a process performed by the original email document providing unit 134 of the UTM device 1. In other words, the process of accepting the original document reception request sent in step S57 and providing the received original email document in step S58 is a process performed by the original email document providing unit 134 of the UTM device 1. Alternatively, the process of accepting the original document reception request sent in step S59 and then executing steps S60 to S61 is a process performed by the original email document providing unit 134 of the UTM device 1.

[0083] Next, we will explain the operation when a user checks the received email image displayed on the display unit of PC3 and determines that the corresponding original received email is unnecessary. Assume that the user of PC3 selects the delete button B3 of the received email image (FIG. 3(B)) displayed on the display unit of PC3 in step S56 of Fig. 6. In this case, a program associated with the selected delete button B3 is executed in the browser running on PC3, and a request to delete the original is formed and sent to the UTM device 1 via LAN2 (step S62).

[0084] The original document deletion request includes information that identifies the received original email, and is received and interpreted by the HTTP server unit of the UTM device 1, and in accordance with the interpreted content, a process is executed to delete the desired received original email from the original email storage unit 111. In this way, the process of receiving the original document deletion request sent from PC 3 by the process of step S62, interpreting it, and deleting the corresponding received original email stored in the original email storage unit 111 is the process performed by the original email deletion unit 135 of the UTM device 1.

[0085] Next, we will explain the operation when a user checks the received email image displayed on the display unit of PC3 and determines that a reply to the corresponding original received email is necessary. Assume that the user of PC3 selects the reply button B2 of the received email image (FIG. 3(B)) displayed on the display unit of PC3 in step S56 of FIG. 6. In this case, PC3 performs a reply operation in the activated mailer, i.e., creates a reply message (reply email) to the sender of the original received email corresponding to the displayed received email image in response to an instruction input from the user (step S63). The mailer creates a reply sending request including the created reply message and sends it to UTM device 1 via LAN2 (step S64).

[0086] The reply request includes information for identifying the original received email, and the mail server unit of the UTM device 1 receives this, creates a reply email to be sent to the sender of the corresponding original received email, and provides this to the mail client unit (step S65). The mail client unit creates a reply sending request including a reply email to be sent (original reply email) from the reply email from the mail server unit, and sends it to the mail server 5 (step S66).

[0087] As a result, the reply email included in the reply sending request is sent via the mail server 5 to the mail server of the sender of the original received email, so that the sender can receive and view it. In this way, the process of accepting a reply sending request created by the user of PC 3 and sending a reply email to the sender of the original received email via the mail server 5 is performed by the mail reply function unit 136 of the UTM device 1. In other words, the processes of steps S65 to S66 are mainly performed by the mail reply function unit 136 of the UTM device 1.

[0088] [Effects of the embodiment] According to the UTM device 1 of the above-described embodiment, which provides an embodiment of an email relay device according to the present invention, the entire original received email is imaged to form a received email image, which can be provided to a PC 3 that has requested the provision of the received email. In the received email image, link information such as a URL is simply display information (image information), so its function as link information can be disabled. This allows the user of the PC 3 to view all of the received email addressed to them as received email images without omission, while disabling clicks on link destination information such as URLs, allowing the recipient to safely and reliably determine for themselves whether the link destination is useful.

[0089] Furthermore, if the user of PC3 determines that the original received email corresponding to the received email image is necessary, the original received email corresponding to the received email image can be provided to PC3 and made available to the user in response to instructions from the user via PC3. Link information also functions effectively in the original received email, so clicking on the link information will take the user to the associated site, where the site can be used. Furthermore, if the original received email has an attachment, the user can see that an attachment is attached in the received email image, but cannot use the attachment. However, once the user has determined that the corresponding original received email is safe, the user can obtain the original received email and use the attachment.

[0090] Furthermore, if the user of PC 3 determines that the original received email corresponding to the received email image is unnecessary, the original received email corresponding to the received email image can be deleted from the original email storage unit 111 in response to an instruction from the user via PC 3. This allows the original received email to be safely identified and deleted if it is spam or fraudulent email such as various solicitation emails, advertising emails, or phishing emails.

[0091] Furthermore, if the user of PC3 determines that it is necessary to reply to the original received email corresponding to the image of the received email, the reply email can be created and sent to the sender of the corresponding original received email in accordance with instructions from the user via PC3. Once the original received email is obtained, it is also possible to create and send a reply email in the same way as in the past. However, since it is now possible to create and send a reply email when the image of the received email is provided, usability is not compromised, and even if it is not possible to determine with certainty whether the received email is safe, a reply email can be created and sent safely.

[0092] [Variations] In the above-described embodiment, the link information included in the received email (received electronic mail) is a URL, but this is not limited to this. The present invention is also effective when link information is associated with an image portion having a predetermined display area, such as a pictogram called an icon or a reduced image called a thumbnail, included in the received email. Even in such a case, by converting the original received email into an image and using it as the received email image, the link information associated with the image portion included in the original received email can also be invalidated. Therefore, clicking on such an image portion in the received email image will not transition to the linked site.

[0093] In the above-described embodiment, when an image of a received email is received, a reply email can be sent to the sender of the corresponding original email. Similarly, when an image of a received email is received, the corresponding original email can be forwarded to a third party. In this case, a forward button can be provided on the image of the received email. When this button is selected, a forwarding instruction can be input, and the original email corresponding to the displayed image of the received email can be forwarded to the intended recipient.

[0094] In the above-described embodiment, as shown in FIG. 3(B), the original button (first operation indicator) B1, the reply button (second operation indicator) B2, and the delete button (third operation indicator) B3 are provided within the received email image. However, this is not limited to this. The original button B1, the reply button B2, and the delete button B3 may be provided as separate images from the received email image, and may be displayed together with the received email image so that they can be selected.

[0095] Furthermore, the above-described embodiment is not limited to providing the original button B1, reply button B2, and delete button B3 as shown in FIG. 3(B). As described above, the reply button B2 and delete button B3 are displayed on the display screen of the PC 3, and when selected, a program (processing procedure) is associated with them that executes a process, such as forming a desired request and sending it to the UTM device 1. For this reason, for example, the first operator may be a clickable location on the display screen indicated by text information, such as "Click here to obtain the original copy of the received email." Furthermore, for example, the first operator indicator may be provided as a so-called icon composed of a picture, symbol, figure, or these together with text. When selected, the desired process may be executed.

[0096] Also, for example, a display message or voice message such as "If you want to obtain the original copy of the received email, press '1'" can be output. In response to this, when the specified operation key, in this example the numeric key '1', is pressed, the PC 3 can request the UTM device 1 to provide the original copy of the received email, and the original copy of the received email can be provided. The second and third operation indicators can be configured in a similar manner. In this way, the operation indicators can be displayed operation buttons, characters, icons, or hardware keys on the PC 3 that are operated in response to the display message or voice message, which can be used together with the image of the received email.

[0097] Furthermore, in the above-described embodiment, an example in which the email relay device of the present invention is applied to a UTM device has been described, but the present invention is not limited to this. A dedicated email relay device for relaying emails between the Internet 4 and PC 3 can also be provided. In this case, the security function unit 120 of the UTM device 1 shown in FIG. 2 is not provided. Alternatively, the email relay device of the present invention can be realized by providing an original email storage unit 111, an email image storage unit 112, and an email safety unit 130 to a device that relays emails sent and received. For example, the present invention can be applied to various devices, such as gateway devices, that are provided between the Internet and a LAN or terminal device and relay emails.

[0098] 2 can also be realized as functions of the control unit 102 by a program executed by the control unit 102. That is, the functions of the login processing unit 131, the mail acquisition unit 132, the imaging processing unit 133, the original mail providing unit 134, the original mail deletion unit 135, and the mail reply function unit 136 of the mail safety unit 130 can be realized by a program executed by the control unit 102. [Explanation of symbols]

[0099] 1...UTM device, 101T...connection end, 101...WAN I / F, 102...control unit, 103...storage device, 104T...connection end, 104...LAN I / F, 111...original email storage unit, 112...email image storage unit, 120...security function unit, 130...email safety unit, 131...login processing unit, 132...email acquisition unit, 133...imaging processing unit, 134...original email provision unit, 135...original email deletion unit, 136...email reply function unit, 2...LAN, 3, 3(1), 3(2), 3(3)...PC, 4...Internet, 5...email server, 6(1)...PC, 7(1)...smartphone, BS(1)...base station, B1...original button, B2...reply button, B3...delete button

Claims

1. a mail acquisition means for acquiring a target received mail from a predetermined mail server device in response to a request for receiving the received mail from a subordinate terminal device, and recording the acquired received mail as an original in a mail original storage means; an image processing means for forming a received mail image by converting the entire received mail original stored in the mail original storage means into image data, and providing the received mail image to the terminal device that is the sender of the reception request; An email relay device comprising:

2. 2. The email relay device according to claim 1, The image processing means forms an original provision request including information relating to the original of the received email corresponding to the received email image, and makes available a first operation indicator for making the request from the terminal device together with the received email image, and an original mail providing means for reading out the original received mail associated with the association information from the original mail storage means and providing the original received mail to the terminal device when the original request is sent from the terminal device that provided the received mail image.

1. An email relay device comprising:

3. 2. The email relay device according to claim 1, The image processing means forms an original deletion request including information relating to the original of the received email corresponding to the received email image, and makes available a second operation indicator for making the request from the terminal device together with the received email image; and a mail original deletion means for deleting the received mail original associated with the association information from the mail original storage means when the original deletion request is sent from the terminal device that provided the received mail image.

1. An email relay device comprising:

4. 3. The email relay device according to claim 1, wherein: The image processing means forms a reply request including information relating to the original of the received email corresponding to the received email image, and makes available a third operation indicator for requesting from the terminal device together with the received email image; and a mail reply processing means for, when the reply request is sent from the terminal device that provided the received mail image, accepting the reply content from the terminal device, creating a reply mail to the original received mail associated by the association information, and transmitting the reply mail to the sender of the original received mail.

1. An email relay device comprising:

Images