COMMUNICATION CONTROL DEVICE, COMMUNICATION SYSTEM, COMMUNICATION CONTROL METHOD, AND PROGRAM

Abstract

To provide a device, system, method and program capable of acquiring a pair of connection information of a device and identification information of the device without changing the mechanism of a DHCP server.SOLUTION: A communication control device includes storage means for storing identification information for identifying registered devices, searching means for sending packets onto a network to search for devices connected to the network, acquisition means for acquiring, from a device responding to the packets, address information assigned to the device and identification information of the device, and communication control means for controlling communication of a registered device by using connection information in which address information of a device whose acquired identification information matches identification information stored in the storage means is associated with the identification information stored in the storage means.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to an apparatus, a system, and a method for controlling communications, and a program for causing a computer to execute the control. [Background technology]

[0002] To connect a device such as a PC (Personal Computer) to a network, it is necessary to set network-related information such as an IP (Internet Protocol) address in advance. Setting this information manually is time-consuming and can lead to configuration errors.

[0003] Therefore, a DHCP (Dynamic Host Configuration Protocol) server is placed on the network, and the DHCP server dynamically assigns IP addresses to devices and sets them automatically. In order to make effective use of address resources, DHCP sets a period during which the IP address assigned by the DHCP server can be used.

[0004] However, DHCP leaves the use of the IP address after the expiration date up to the client, so there is a problem that the Internet can be accessed illegally from a LAN (Local Area Network) even after the IP address has expired.

[0005] In view of this problem, a technique has been proposed in which a firewall system is installed between a LAN and the Internet, and Internet access control information is registered in the firewall system on a per-device MAC (Media Control) address basis only during the period in which the DHCP server is assigning an IP address to the device (see, for example, Patent Document 1). Summary of the Invention [Problem to be solved by the invention]

[0006] However, the above technology requires that the IP address and MAC address pair be known in advance, which poses the problem that the DHCP server mechanism must be changed and that information must be obtained from the DHCP server.

[0007] The present invention is devised to solve the above-mentioned problems, and aims to provide an apparatus, system, method, and program that can obtain a pair of address information assigned to a device and identification information of the device without changing the mechanism of the DHCP server. [Means for solving the problem]

[0008] According to the present invention, there is provided a communication control device for controlling communication, comprising: A storage means for storing identification information for identifying a registered device; On the network to search for devices connected to the network At regular time intervals a lookup means for sending packets; an acquisition means for acquiring address information assigned to a device and identification information of the device from the device that responded to the packet; The address information of the device whose acquired identification information matches the identification information stored in the storage means is associated with the identification information stored in the storage means. , the associated pair of identification information and address information Connection Information As A communication control means for controlling communication of a registered device using the The present invention provides a communication control device including: Effect of the Invention

[0009] According to the present invention, it is possible to obtain a pair of address information assigned to a device and identification information of the device without changing the mechanism of the DHCP server. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 illustrates an example of the configuration of a communication system. [Diagram 2] FIG. 2 is a diagram for explaining a network connected to a communication control device. [Diagram 3] FIG. 4 is a diagram showing an example of network settings of each device. [Figure 4] FIG. 2 is a diagram for explaining the address allocation range of a DHCP server. [Diagram 5] FIG. 2 is a diagram illustrating an example of a hardware configuration of a communication control device. [Figure 6] FIG. 2 is a diagram showing an example of a hardware configuration of an information processing apparatus. [Figure 7] FIG. 2 is a block diagram showing an example of a functional configuration of a communication control device. [Figure 8] FIG. 4 is a diagram showing a first example of a UI screen of the communication control device. [Figure 9] FIG. 13 is a diagram showing a second example of a UI screen of the communication control device. [Figure 10] FIG. 13 is a diagram showing a third example of a UI screen of the communication control device. [Figure 11] FIG. 4 is a sequence diagram showing an example of control executed by a communication control device. [Figure 12] FIG. 2 is a diagram showing an example of a table to be referred to when the communication control device controls communication; [Figure 13] FIG. 4 is a diagram for explaining an IP address of a communication control device. [Figure 14] FIG. 13 shows a first example of a packet flow when printing from a PC to an MFP. [Figure 15] FIG. 11 shows a second example of the packet flow when printing from a PC to an MFP. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, the present invention will be described with reference to embodiments, but the present invention is not limited to the embodiments described below.

[0012] 1 is a diagram showing an example of the configuration of a communication system. The communication system includes an interface box (hereinafter referred to as Box) 10 as a device for controlling communication, a multifunction peripheral (MFP) 11 as an information processing device, and one or more networks (Net_A to Net_C) 12 to 14.

[0013] A PC (PC_A) 15, a DHCP server (DHCP_S_A) 16, and a router (RA) 17 are connected to the network (Net_A) 12. The router 17 is used as a default gateway by the network 12, and connects the network 12 to other networks. The default gateway is a node for connecting the network 12, which is an internal network, to other networks, which are external networks.

[0014] A PC (PC_B) 18, a DHCP server (DHCP_S_B) 19, and a router (RB) 20 are connected to the network (Net_B) 13. The router 20 connects the network 13 to other networks.

[0015] A PC (PC_C) 21 and a router (RC) 22 are connected to the network (Net_C) 14. The router 22 connects the network 14 to a network (Net_I) 24 that is connected to the Internet 23. The networks 12 to 14 are all private networks and are not directly connected to the Internet 23.

[0016] Here, the degree of security (fewer viruses and attacks from third parties) for each network is Net_A>Net_B>Net_C, making network 12 the most secure network.

[0017] Box 10 has multiple connection ports, and MFP 11 and networks 12 to 14 are connected to each port. Box 10 has one port that is a dedicated port for connecting a device whose communications are to be controlled, and in the example shown in FIG. 1, it is the port for MFP 11. MFP 11 is connected to the dedicated port using a cable or the like. The other ports are ports for connecting one or more networks 12 to 14. Note that multiple MFPs 11 may be connected to one port via a relay device such as a switching hub. Note that a switching hub is a device that has a function of checking the destination and transmitting only to related devices.

[0018] Box 10 directly transfers access from the most secure network 12 to MFP 11, and also directly transfers access from MFP 11 to network 12. Here, such direct transfer is called bridge transfer, and network 12 is called a bridge segment. The bridge segment includes devices on network 12 (PC 15, DHCP server 16, router 17). Basically, all of the functions of MFP 11 can be used from the bridge segment.

[0019] For this reason, the MFP 11 communicates with the DHCP server 16 on the network 12, and uses the DHCP mechanism to configure network-related settings such as an IP address, a subnet mask, and a default gateway. At this time, the DHCP communication from the MFP 11 passes through the Box 10.

[0020] Box 10 performs network address port translation (NAPT) for access from networks 13 and 14 other than network 12, and automatically rewrites the destination IP address when forwarding. Here, such address conversion and forwarding is called packet forwarding, and networks 13 and 14 are called packet forwarding segments. The packet forwarding segment includes devices on networks 13 and 14 (PC 18, DHCP server 19, router 20, PC 21, router 22). Some functions of MFP 11 can be used from the packet forwarding segment. Note that a packet is information exchanged in communication, and is data to which control information such as source and destination information has been added.

[0021] The functions of the MFP 11 include a scanner function, a copy function, a print function, a FAX sending / receiving function, a communication function, etc. Therefore, all of these functions of the MFP 11 can be used from a PC 15 or the like on the network 12, but only some of the functions such as the print function can be used from a PC 18 or the like on the network 13 and a PC 21 or the like on the network 14. The functions that can be used can be set in advance.

[0022] Since devices on the network 13 communicate with the MFP 11 by NAPT communication, the DHCP server 19 does not execute the process of assigning an IP address or the like to the MFP 11.

[0023] 1, the controlled device connected to the Box 10 is the MFP 11, but the controlled device is not limited to the MFP. The controlled device may be, for example, a PJ (Projector), an IWB (Interactive White Board: a white board having an electronic blackboard function capable of mutual communication), an industrial machine, an imaging device, a sound collecting device, a medical device, a network home appliance, an automobile (Connected Car), a notebook PC (Personal Computer), a mobile phone, a smartphone, a tablet terminal, a game machine, a PDA (Personal Digital Assistant), a wearable PC, a desktop PC, or the like.

[0024] Also, one PC 15, 18, 21 is connected to each of the networks 12 to 14, but two or more PCs or other devices may be connected. The PCs 15, 18, 21 can communicate with the MFP 11 to print documents created by the PCs. Similarly, the DHCP server 16, the router 17, the DHCP server 19, the router 20, and the router 22 on the networks 12 to 14 can also communicate with the MFP 11. Devices connectable to the Internet 23 can also communicate with the MFP 11 via the Internet 23 based on communication control settings by the router 22, etc. However, when the MFP 11 is used via the networks 13 and 14, available functions are limited.

[0025] 1, the MFP 11 and network 12 are configured to perform bridge transfer, but the present invention is not limited to this, and the MFP 11 and network 13, or the MFP 11 and network 14 may be configured to perform bridge transfer. Also, although no DHCP server is installed on network 14, a DHCP server may be installed.

[0026] Each of the networks 12 to 14, 24 will be described with reference to FIG. 2. Each of the networks 12 to 14, 24 has a network address, which is the IP address of the network itself. An IP address is address information assigned to identify a destination or source. In Internet Protocol version 4 (IPv4), an IP address is composed of four sets of numbers expressed in decimal notation and separated by dots (.), and has a network portion for identifying the network and a host portion for identifying a host that is a device on the network. Each of the networks 12 to 14, 24 has a netmask (also called a subnet mask) that indicates the extent of the network portion.

[0027] For example, network 12 indicated by NetA has a network address of "192.168.1.0" and a netmask of " / 24", which means that the first three pairs of numbers "192", "168", "1", and "0" that make up the IP address (up to the 24th bit, since each pair is represented by 8 bits) make up the network section, and the remaining fourth pair "0" makes up the host section. An IP address with a host section of 0 is a network address, and an IP address with a host section of 255 is a broadcast address. A broadcast address is an IP address used to send data to all hosts on the same network at once. Each host is assigned a host section of 1 to 254, excluding 0 and 255.

[0028] The DHCP servers 16 and 19 manage network addresses and netmasks, and upon receiving an address setting request, assign an IP address to the requesting device based on the managed network address and netmask. The DHCP servers 16 and 19 hold information on already assigned IP addresses, and assign an IP address that has not yet been assigned to the requesting device.

[0029] Devices on the networks 12, 13 request an IP address from the DHCP server 16, 19 according to their settings. If the setting is to automatically obtain an IP address, the devices on the networks 12, 13 request an IP address from the DHCP server 16, 19 and set the IP address assigned by the DHCP server 16, 19. On the other hand, if the setting is to manually set, the administrator inputs the IP address into a setting screen and sets it manually. Devices on the networks 14, 24 have no DHCP server, so their IP addresses are set manually.

[0030] The devices on the networks 12 to 14 and 24 communicate using a MAC address, which is identification information for uniquely identifying each device, and a set IP address.

[0031] The network settings of each device will be described with reference to Fig. 3. The devices to be configured for network settings are a Box 10, an MFP 11, a PC 15, a DHCP server 16, a router 17, a PC 18, a DHCP server 19, a router 20, a PC 21, and a router 22. The example shown in Fig. 3 further includes SMB (Server Massage Block) servers (SMB_S_B, SMB_S_C) as file servers used for file sharing, print sharing, and the like.

[0032] When the IP address / subnet mask and default gateway shown in FIG. 3 are set manually, a fixed address (e.g., 192.168.1.1 / 24) is set by input; when they are set automatically, an address assigned by the DHCP server is set.

[0033] To reduce the operational load, the Box 10, MFP 11, PC 15, etc. distribute network settings by DHCP, allowing the DHCP servers 16, 19 to manage the network settings without setting IP addresses on each device. The DHCP servers 16, 19 have a function to dynamically change IP addresses, as well as a function to fix network settings to MAC addresses assigned to devices as identification information for identifying the devices. This makes it possible to operate devices with fixed addresses.

[0034] 4 is a diagram explaining the address assignment range of the DHCP servers 16, 19. The DHCP servers 16, 19 manage the range of IP addresses that can be assigned, and this range is set as the address assignment range. Note that the IP addresses that can be assigned to each device can be set to IP addresses outside the IP address assignment range managed by the DHCP servers 16, 19. The IP addresses can be set by a method other than DHCP.

[0035] 4 shows that the host portion of the IP address can be assigned between 6 and 20. Therefore, "192.168.1.6" can be assigned to Box 10 on network 12, "192.168.1.7" can be assigned to MFP 11, and "192.168.1.8" can be assigned to PC 15.

[0036] Although we have shown network configuration using DHCP for IPv4, DHCP can also be used for version 6 (IPv6). In addition, the router advertisement technique for dynamic allocation from the router can also be used as a method for specifying IP addresses.

[0037] 5 is a diagram showing an example of a hardware configuration of Box 10 constituting the communication system. Box 10 includes a central processing unit (CPU) 30, a read only memory (ROM) 31, a random access memory (RAM) 32, a hard disk (HD) 33, a HDD controller 34, a display device 35, an input / output I / F 36, a communication I / F 37, a data bus 38, and an input device 39, similar to a typical PC.

[0038] The CPU 30 controls the entire Box 10 and controls communication with the MFP 11 connected to the Box 10. The ROM 31 stores programs used to drive the CPU 30, such as an IPL (Initial Program Loader). The RAM 32 provides a working area for the CPU 30. The HD 33 stores various data such as programs. The HDD controller 34 controls reading and writing of various data from and to the HD 33 under the control of the CPU 30. The display device 35 displays various information such as a cursor, a menu, a window, characters, and an image.

[0039] The input / output I / F 36 is an interface for connecting the display device 35 and the input device 39. The communication I / F 37 is an interface for connecting the MFP 11 and the networks 12 to 14 and communicating with the devices on the MFP 11 and the networks 12 to 14. The data bus 38 is an address bus, a data bus, or the like for electrically connecting the components such as the CPU 30. The input device 39 is a device for inputting characters, numbers, various instructions, etc., selecting and executing various instructions, selecting a processing target, moving a cursor, etc. The display device 35 and the input device 39 do not have to be separate devices, and a single device having both functions, such as a display with a touch panel, may be used.

[0040] 6 is a diagram showing an example of a hardware configuration of an MFP 11 as an electronic device constituting a communication system. The MFP 11 includes a controller 40, a short-range communication circuit 41, an engine control unit 42, an operation panel 43, and a network I / F 44.

[0041] The controller 40 includes a CPU 50, which is the main part of the computer, a system memory (MEM-P) 51, a north bridge (NB) 52, a south bridge (SB) 53, an ASIC (Application Specific Integrated Circuit) 54, a local memory (MEM-C) 55, an HDD controller 56, and a HD 57. The NB 52 and the ASIC 54 are connected by an AGP (Accelerated Graphics Port) bus 58.

[0042] The CPU 50 is a control unit that performs overall control of the MFP 11. The NB 52 is a bridge for connecting the CPU 50 with the MEM-P 51, the SB 53, and the AGP bus 58, and has a memory controller that controls reading and writing to the MEM-P 51, a PCI (Peripheral Component Interconnect) master, and an AGP target.

[0043] The MEM-P51 includes a ROM 51a which is a memory for storing programs and data for implementing the various functions of the controller 40, and a RAM 51b which is used for developing the programs and data, and as a drawing memory during memory printing, etc. The programs stored in the RAM 51b may be provided by being recorded in a computer-readable recording medium such as a CD-ROM, CD-R, or DVD in the form of an installable or executable file.

[0044] The SB53 is a bridge for connecting the NB52 to the PCI device and the peripheral device. The ASIC54 is an IC for image processing purposes having hardware elements for image processing, and plays the role of a bridge connecting the AGP bus 58, the PCI bus 59, the HDD controller 56, and the MEM-C55. The ASIC54 includes a PCI target and an AGP master, an arbiter (ARB) that is the core of the ASIC54, a memory controller that controls the MEM-C55, and a plurality of DMACs (Direct Memory Access Controllers) that rotate image data using hardware logic or the like. The ASIC54 also includes a PCI unit that transfers data between the scanner unit 60 and the printer unit 61 via the PCI bus 59. The ASIC54 may be configured to connect a USB (Universal Serial Bus) interface or an IEEE1394 (Institute of Electrical and Electronics Engineers 1394) interface.

[0045] MEM-C55 is a local memory used as a copy image buffer and a code buffer. HD57 is a storage for storing image data, font data used during printing, and forms. HD57 controls the reading and writing of data from and to HD57 under the control of CPU50. AGP bus 58 is a bus interface for a graphic accelerator card proposed to speed up graphic processing, and by directly accessing MEM-P51 at high throughput, the graphic accelerator card can be made faster.

[0046] The short-distance communication circuit 41 is a communication circuit that uses NFC (Near Field Communication), Bluetooth (registered trademark), or the like.

[0047] The engine control unit 42 is composed of a scanner unit 60 and a printer unit 61. The operation panel 43 is equipped with a panel display unit 43a such as a touch panel that displays current setting values, a selection screen, etc. and accepts input from the user, and an operation panel unit 43b consisting of a numeric keypad that accepts setting values ​​for image formation conditions such as density setting conditions, a start key that accepts a copy start instruction, etc.

[0048] The controller 40 controls, for example, drawing, communication, and input from the operation panel 43. The scanner unit 60 or the printer unit 61 includes an image processing unit that performs error diffusion, gamma conversion, and the like.

[0049] The MFP 11 can sequentially switch between a document box function, a copy function, a printer function, and a facsimile function by using an application switching key on the operation panel 43. When each function is selected, the corresponding mode is entered.

[0050] The network I / F 44 is an interface that is connected to the Box 10 and that performs data communication with devices on the networks 12 to 14 via the Box 10. The short-range communication circuit 41 and the network I / F 44 are electrically connected to the ASIC 54 via a PCI bus 59.

[0051] 7 is a block diagram showing an example of the functional configuration of Box 10. Each function of Box 10 can be realized by a processing circuit such as CPU 30. The processing circuit includes a processor programmed to execute each function by software, such as a processor implemented by an electronic circuit, and devices such as ASIC, DSP (Digital Signal Processor), FPGA (Field Programmable Gate Array), and conventional circuit modules designed to execute each function described above.

[0052] The Box 10 includes transmission / reception units 70 to 73 functioning as a transmission unit and a reception unit, a search unit 74, an acquisition unit 75, communication control units 76 to 78, a management unit 79, and a storage unit 80.

[0053] The transmitting / receiving unit 70 transmits and receives data etc. with the MFP 11. The transmitting / receiving unit 71 transmits and receives data etc. with devices on the network 12. The transmitting / receiving unit 72 transmits and receives data etc. with devices on the network 13. The transmitting / receiving unit 73 transmits and receives data etc. with devices on the network 14.

[0054] Communications control unit 76 bridges network 12 and MFP 11, transfers access from network 12 directly to MFP 11, and transfers access from MFP 11 directly to network 12. Communications control unit 76 also sends packets received from networks 13 and 14 via communications control units 77 and 78 to MFP 11, and transmits packets from MFP 11 to networks 13 and 14 via communications control units 77 and 78.

[0055] The communication control units 77 and 78 perform NAPT, send packets to the MFP 11 via the communication control unit 76, and receive packets from the MFP 11 via the communication control unit 76.

[0056] The search unit 74 sends packets (search packets) onto the network 12 in order to search for devices on the network 12, and periodically searches for the MFP 11. This is because, since the IP address that the DHCP server 16 assigns to the MFP 11 has a time limit, the search unit 74 obtains a reallocated IP address after the time limit has expired.

[0057] Furthermore, the search unit 74 can search for the MFP 11 not periodically, or in addition to periodically, after the Ethernet (registered trademark) has been linked down and then linked up. The Ethernet (registered trademark) is one of the wired LANs (Local Area Networks). A link down is when a cable is pulled out, causing a state in which communication is not possible. A link up is when a state in which communication is not possible is changed to a state in which communication is possible, causing a pulled out cable to be plugged in, for example.

[0058] The search unit 74 uses multicast to send search packets onto the network 12 and search for devices on the network 12. Multicast is a method of simultaneously transmitting the same data to multiple specific recipients.

[0059] When searching for devices using mDNS, the search unit 74 identifies the type of service and searches for devices that provide that type of service. The service type is, for example, "_printer._tcp" or "_ipp._tcp", the former indicating printing and the latter indicating that print data can be exchanged using a TCP / IP (Transmission Control Protocol / Internet Protocol) network. The search unit 74 simultaneously transmits packets that identify these service types to multiple devices on the network 12 by multicast. Note that the service type is not limited to printing, and may be copying, document reading, fax transmission and reception, etc.

[0060] Among the multiple devices on network 12, devices that can provide the above type of service respond to the packet. In the above example, since MFP 11 is a device with a printing function, it responds by including its host name or domain name to the effect that it has the printing function. Host names and domain names are names registered to identify and manage devices on the network.

[0061] MFP 11 stores the IP address assigned by DHCP server 16 in association with a host name or a domain name. Acquisition unit 75 specifies the host name or domain name to MFP 11 from which a response is received, requests name resolution, and acquires the IP address assigned to MFP 11.

[0062] The device searched for by the search unit 74 is not limited to one device. This is because there may be multiple devices on the network that can provide the same service. In this case, the acquisition unit 75 acquires multiple IP addresses. Also, some devices may have two IP addresses, IPv4 and IPv6, and even if the search unit 74 searches for one device, multiple IP addresses may be acquired.

[0063] The acquisition unit 75 creates a list of the acquired IP addresses, requests a device having a corresponding MAC address according to the list, and acquires the MAC address corresponding to the IP address from the device. The MAC address can be acquired from the IP address by performing address resolution using ARP (Address Resolution Protocol) when performing ICMP (Internet Control Message Protocol) ECHO (ping).

[0064] Here is a brief explanation of IP addresses and MAC addresses. A MAC address is identification information that uniquely identifies a device, and is information that never changes. On the other hand, an IP address is address information that indicates which network a device is on, has a limited time period, and is reassigned when the period expires. It is possible to identify a device using only the MAC address, but it is not possible to know which network the device is on. With only an IP address, since it is assigned for a limited time, it is not possible to know whether the device is actually the device with which the communication is taking place. For this reason, both MAC addresses and IP addresses are used as a pair in communications.

[0065] The storage unit 80 stores the MAC addresses of the devices to be controlled that have been registered in advance. The management unit 79 compares the MAC address acquired by the acquisition unit 75 with the MAC addresses stored in the storage unit 80 and determines whether the two match. The management unit 79 associates the IP address corresponding to the MAC address that has been determined to match with the MAC address stored in the storage unit 80, creates a pair of the MAC address and the IP address, and stores the pair in the storage unit 80 as connection information.

[0066] The communication control units 76-78 use the connection information stored in the storage unit 80 to control the communications of the MFP 11. The communication control units 76-78 permit access to an IP address that corresponds to a MAC address in the connection information, enabling communications with the MFP 11. On the other hand, the communication control units 76-78 deny access to an IP address that does not correspond to a MAC address.

[0067] 7 is unnecessary when a manually fixed address is set as the IP address of MFP 11. For this reason, the processes by search unit 74, acquisition unit 75, and management unit 79 are executed only when DHCP is used.

[0068] 8 is a diagram showing an example of an initial state screen as a first example of a UI (User Interface) screen for setting an IP address. The administrator sets whether or not to use DHCP for the MFP 11 and each segment. The UI screen has a check box 90 for setting whether or not to use DHCP. Also, it has an input field 91 for inputting an IP address when DHCP is not used.

[0069] The IPv4 for MFP 11, segments 1 to 3 are the IP addresses of MFP 11 and networks 12 to 14, and the subnet mask for segments 1 to 3 are the subnet masks of networks 12 to 14. The gateways for segments 1 to 3 are the IP addresses of routers 17, 20, and 22 on networks 12 to 14. The SMB servers for segments 2 and 3 are the IP addresses of the SMB servers on networks 13 and 14.

[0070] 9 is a diagram showing a second example of a UI screen for setting an IP address, which is an example of a screen when DHCP is not used. When DHCP is not used, the check box 90 is not checked, and the IP address is entered and set in the input field 91.

[0071] If DHCP is not used, IP addresses must be entered into all of the input fields 91. When entering the addresses, it is necessary to be careful not to make any input errors, which makes operation complicated.

[0072] 10 is a diagram showing an example of a screen when DHCP is used, as a third example of a UI screen for setting an IP address. When DHCP is used, it is not necessary to input an IP address, but only to check a check box 90. Note that segment 3 is network 14, which does not have a DHCP server installed, so an IP address is input and set.

[0073] By configuring to use DHCP, there is no need to set the IP address, subnet mask, or default gateway, simplifying operation and reducing the operational load. Note that a DHCP server may also be installed on segment 3, and all segments 1 to 3 may be configured to use DHCP. In this case, there is no need to enter IP addresses, etc.

[0074] Fig. 11 is a sequence diagram showing an example of a process for acquiring connection information when a setting is made to use DHCP. In Fig. 11, a functional unit including a search unit 74, an acquisition unit 75, a management unit 79, and a storage unit 80 is referred to as an MFP monitor 81.

[0075] This process is executed periodically while Box 10 is operating. If the MFP 11 is not connected to Box 10 but the status shows MFP connected, the status transitions to MFP not connected (S1). If there is no MFP connection information (IP address and MAC address pair) but it shows that there is (saved), the MFP connection information is deleted (S2). It is determined whether the status is MFP connected and MFP connection information is present, and if both are met, the process ends.

[0076] Such cases may include when the cable connecting Box 10 and MFP 11 becomes disconnected, when MFP 11 is powered off, when a communication failure occurs between Box 10 and MFP 11, or when the IP address assigned by the DHCP server expires.

[0077] When the cable is reconnected, the power is turned on, a communication failure is recovered, or an IP address is reassigned, the status is changed to "MFP connected," and MFP connection information is created and saved by the following process. At this time, it is assumed that MFP 11 has requested an IP address from DHCP server 16, and that DHCP server 16 has assigned an IP address.

[0078] If the setting value of the MFP 11 is a MAC address, mDNS is used to search for the MFP 11 in order to obtain an IP address and save the connection information (S3). In mDNS, a service type is specified to search for a corresponding device. Devices that can provide the specified type of service return a search reply (response). In this example, the MFP 11 returns the response (S4). The response includes the host name or domain name of the MFP 11.

[0079] Since the response from the MFP 11 does not include an IP address, a name resolution (IP address resolution) is requested of the MFP 11 (S5). In other words, a request is made to the MFP 11 to provide the IP addresses of devices on the network 12 that have the host name or domain name obtained in the response. Once all IP addresses for the searched devices have been obtained, an array of destination IP addresses, i.e., a list of IP addresses, is created (S6).

[0080] Incidentally, if the setting value of the MFP 11 is an IP address, there is no need to obtain the IP address, so a list of IP addresses is created from the setting value (S7).

[0081] After creating the destination IP address array, a source IP address array is created (S8). The source IP address array is a list of the IP addresses of Box 10 itself. If the IP address of Box 10 itself is set to be assigned by DHCP server 16 on network 12, it is assigned by DHCP server 16. If it is set manually, it is a manually set fixed IP address.

[0082] Since the corresponding MAC address cannot be found from the list of IP addresses, ARP is performed using ICMP ECHO based on the IP address to obtain the MAC address that corresponds to the IP address (S9).

[0083] The acquired MAC address corresponds to the IP address used for acquisition, and is compared with the set MAC address to confirm whether the MAC addresses match (S10). The IP address corresponding to the matching MAC address is associated with the set MAC address and saved as connection information (S11). The connection information is stored in the storage unit 80, and can be saved in a table called an ARP table, for example. By saving the information in the ARP table, the corresponding address can be found by referring to this table from the next time.

[0084] Once the correspondence between IP addresses and MAC addresses is determined, it becomes possible to control communications using that correspondence. In order to control that communications, it is necessary to set access control. For communications between network 12 and MFP 11, a basic communication rule setting is performed (S12), and for communications between networks 13, 14 and MFP 11, an IP setting of a packet forwarding segment is performed (S13). The basic communication rule setting is a setting for directly forwarding packets, and the IP setting of the packet forwarding segment is a setting of an IP address required for NAPT conversion. When these settings are completed, the process ends (S14).

[0085] The communication control executed by the communication control unit 76 will be described with reference to Fig. 12. In the case of data from the transmitting / receiving unit 70, first, it is confirmed whether or not the MAC address of the sender that sent the data to the transmitting / receiving unit 70 matches the MAC address of the MFP 11. The IP address of the MFP 11 and the corresponding MAC address are saved as connection information. Therefore, whether or not they match can be determined by referring to the connection information.

[0086] If they do not match, this indicates that the device connected to the transmission / reception unit 70 is not the MFP 11. For this reason, the data is dropped (discarded). If they match, secondly, it is confirmed whether the IP address of the sender matches the address of the MFP 11. Whether they match can also be determined by referring to the connection information.

[0087] If they match, the data is transferred to a transceiver that transmits the data to the network to which the destination device is connected. This allows the data to be sent from the MFP 11 to the destination device. If they do not match, there are no particular conditions to check, and the data is dropped. Therefore, the data is controlled to be transferred only when both the IP address and MAC address of the sender match both the IP address and MAC address of the MFP 11.

[0088] Next, a description will be given of the data from the transmitting / receiving unit 71. The same processing is performed for the data from the transmitting / receiving units 72 and 73, so a description of the data from the transmitting / receiving units 72 and 73 will be omitted here.

[0089] First, it is confirmed whether the MAC address of the sender that sent the data to the transceiver unit 71 matches the MAC address of the MFP 11. If they match, the device connected to the transceiver unit 71 is the MFP 11, and since it is assumed that the MFP 11 will be connected to the transceiver unit 70, the data is dropped.

[0090] If they do not match, secondly, it checks whether the source IP address matches the IP address of the MFP. If they match, the data is dropped. If they do not match, there are no particular conditions to check and the data is forwarded. Therefore, only when the source IP address and MAC address do not match both the IP address and MAC address of the MFP 11, i.e., when they indicate a device other than the MFP 11, control is exercised so that the data is forwarded.

[0091] Box 10 changes the range of available functions depending on the segment of the communication partner. For example, in the case of communication with a bridge segment, Box 10 makes all functions available. Therefore, if a request from the bridge segment is a print request, Box 10 transfers the print request to MFP 11, and if the request is a document read request, Box 10 transfers the document scan request.

[0092] On the other hand, in the case of communication with the packet transfer segment, Box 10 permits the use of only some functions. Therefore, if the permitted function is a print function, when a print request comes from the packet transfer segment, Box 10 transfers the print request to MFP 11, but does not transfer the read request to MFP 11 even if a document read request comes.

[0093] 13 to 15, the flow of packets when printing from PCs 15, 18 on networks 12, 13 to MFP 11 using communication control units 76, 77 will be described. Note that the flow of packets when printing from PC 21 on network 14 to MFP 11 is similar to the flow of packets when printing from PC 18 on network 13 to MFP 11, so a description thereof will be omitted here. Also, the flow of packets from MFP 11 to devices on networks 12 to 14 is simply the reverse of the packet flow described here, so a description thereof will also be omitted.

[0094] The communication control unit 76 has an IP address (BRI_A) that serves as the source of packets sent from the transmitting / receiving units 72 and 73, i.e., packets sent from devices on the networks 13 and 14, to the MFP 11. When the IP address is set to be automatically acquired by the DHCP server 16, BRI_A becomes an IP address of the network 12 assigned to the Box 10 by the DHCP server 16. The communication control unit 76 also has an IP address (INT_A) that is used only inside the Box 10 and serves as the source of packets used when transferring packets sent from the MFP 11 to the transmitting / receiving units 72 and 73. INT_A is an IP address that is not used within the network.

[0095] The communication control unit 77 has an IP address (INT_B) used only inside the Box 10, which is the source of packets sent from the transmission / reception unit 72 to the communication control unit 76. Like INT_A, INT_B is also an IP address that is not used within the network. The communication control unit 77 has an IP address (INT_SV_B) used only inside the Box 10 for sending packets received from the communication control unit 76 to a device (SV_B) on the network 13. The communication control unit 77 also has an IP address (MFP_B) for accessing the MFP 11 from a device on the network 13. When set to be automatically obtained by the DHCP server 19, MFP_B becomes an IP address of the network 13 assigned to the Box 10 by the DHCP server 19.

[0096] The communication control unit 78 has an IP address (INT_C) used only inside the Box 10 which is the source of packets sent from the transmission / reception unit 73 to the communication control unit 76. Like INT_A and INT_B, INT_C is also an IP address that is not used within the network. The communication control unit 78 has an IP address (INT_SV_B) used only inside the Box 10 for sending packets received from the communication control unit 76 to a device (SV_B) on the network 14. The communication control unit 78 also has an IP address (MFP_C) for accessing the MFP 11 from a device on the network 14. Each IP address is set manually except for those set to be automatically assigned by DHCP.

[0097] In this example, the destination devices when transmitting packets from the MFP 11 onto the networks 13 and 14 are the servers (SV_B and SV_C), but the present invention is not limited to this.

[0098] An IP address is associated with a port, and a packet is sent to the port associated with the IP address. Figures 14 and 15 explain the flow of a packet using a port.

[0099] 14 is a diagram for explaining the flow of packets during printing from the PC 15 to the MFP 11. The PC 15 is a device on the network 12, and the Box 10 bridges and transfers the packets.

[0100] PC 15 sends a packet using the IP address of MFP 11. At this time, the packet is sent with the destination being the port (9100) of MFP 11 and the source being the port (3000) of PC 15. Since no port conversion is performed in bridge forwarding, the port does not change even when passing through router 17 and Box 10.

[0101] When printing is completed, the MFP 11 returns a response packet indicating that printing has been completed. The return packet also does not change port when passing through the Box 10 and the router 17.

[0102] 15 is a diagram for explaining the flow of packets when printing from the PC 18 to the MFP 11. The PC 18 is a device on the network 13, and the Box 10 performs NAPT and transmits packets to the MFP 11.

[0103] The PC 18 sends a packet using the IP address of the MFP 11. At this time, the packet is sent with the port (9100) of the MFP 11 as the destination and the port (3000) of the PC 18 as the source. The packet is sent to the Box 10 via the router 20. The communication control unit 77 converts the source port (3000) to the port (4000) corresponding to INT_B, and sends the packet to the communication control unit 76. At this stage, the source port of the packet is 4000. The communication control unit 76 converts the source port (4000) to the port (5000) corresponding to BRI_A, and sends the packet to the MFP 11. The source port of the packet sent to the MFP 11 is 5000.

[0104] When printing is completed, the MFP 11 returns a response packet to PC 18 to notify the completion. At this time, the packet is sent with the destination port set to port (5000) and the source port set to port (9100). Within Box 10, the packet is converted in the opposite manner to the packet sent from PC 18 to MFP 11. That is, in communications control unit 76, the destination port is converted from 5000 to 4000, and in communications control unit 77, the destination port is converted from 4000 to 3000. The packet is then sent to PC 18 via router 20 with the destination port set to port (3000).

[0105] As described above, according to the present invention, it is possible to obtain address information assigned to a device and identification information of the device without changing the mechanism of the DHCP server. Although address information has a deadline set by DHCP and is changed by being reallocated, reallocation due to expiration can be handled by periodically executing a process to obtain address information and identification information. In addition, by executing a process to obtain address information and identification information at the time of Ethernet (registered trademark) link-down or link-up, reallocation due to restart of MFP 11 can also be handled.

[0106] While one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and may be modified within the scope of what a person skilled in the art can conceive, such as changing or deleting components of the present embodiment, or adding other components to the components of the present embodiment. In any aspect, as long as the effects of the present invention are achieved, the present invention is included in its scope. [Explanation of symbols]

[0107] 10…Box 11...MFP 12, 13, 14, 24…Network 15, 18, 21…PC 16, 19…DHCP server 17, 20, 22...Router 23. Internet 30…CPU 31...ROM 32…RAM 33…HD 34…HDD controller 35...Display device 36...Input / output interface 37…Communication I / F 38…Data bus 39...Input device 40…Controller 41...Near field communication circuit 42...Engine control unit 43...Operation panel 43a…Panel display section 43b…Operation panel section 44…Network I / F 50…CPU 51…MEM-P 52…NB 53…SB 54...ASIC 55…MEM-C 56…HDD controller 57…HD 58…AGP bus 59...PCI bus 60…Scanner section 61...Printer section 70~73…Transmitter / receiver 74…Search section 75…Acquisition part 76~78…Communication control unit 79…Management Department 80...Storage section 90...Checkbox 91...Input field [Prior art documents] [Patent documents]

[0108] [Patent Document 1] Patent No. 3775378

Claims

1. A communication control device for controlling communication, A storage means for storing identification information for identifying a registered device; a search means for transmitting packets onto a network at regular time intervals in order to search for devices connected to the network; an acquisition means for acquiring, from a device that has responded to the packet, address information assigned to the device and identification information of the device; a communication control means for associating address information of a device whose acquired identification information matches the identification information stored in the storage means with the identification information stored in the storage means, and for controlling communication of the registered device by using a pair of the associated identification information and address information as connection information; A communication control device comprising:

2. 2. The communication control device according to claim 1, wherein the acquisition means requests address information of the responding device based on information contained in the response to the packet, and acquires identification information of the responding device by performing address resolution based on the acquired address information.

3. 3. The communication control device according to claim 1, wherein said search means transmits said packet after a connection with said registered device is disconnected and reconnected.

4. A first communication means for communicating with the registered device; one or more second communication means for communicating with one or more networks; Including, A communication control device as described in any one of claims 1 to 3, wherein the communication control means transfers the first information from the first communication means to one of the second communication means when source connection information contained in the first information received by the first communication means matches connection information stored in the storage means.

5. 5. The communication control device according to claim 4, wherein the communication control means transfers the second information from one of the second communication means to the first communication means when source connection information contained in second information received by one of the second communication means does not match the connection information stored in the storage means.

6. a management means for storing the connection information in the storage means; A communication control device as described in any one of claims 1 to 5, wherein the management means deletes the connection information stored in the storage means when the time-limited address information assigned to the registered device expires or when the connection to the registered device is disconnected.

7. A communication system comprising: a communication control device according to any one of claims 1 to 6; and a device whose communication is controlled by the communication control device.

8. A method for controlling communication by a computer, the computer including a storage means for storing identification information for identifying a registered device, the computer comprising: sending packets onto a network at regular time intervals in order to search for devices connected to the network; obtaining, from a device that has responded to the packet, address information assigned to the device and identification information of the device; a step of associating address information of a device whose acquired identification information matches the identification information stored in the storage means with the identification information stored in the storage means, and using the associated pair of the identification information and the address information as connection information to control communication of the registered device; A method comprising:

9. A program for causing a computer to execute each step included in the method according to claim 8.

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