JP5906820B2 - Communication apparatus and program - Google Patents

Description

  The present invention relates to a communication device and a program.

  In Patent Document 1, any one of a plurality of DHCP (Dynamic Host Configuration Protocol) servers is selected based on the IP (Internet Protocol) address of the DHCP server or the TCP / IP (Transmission Control Protocol / Internet Protocol) configuration information to be presented. A technique for selecting a DHCP server and requesting the selected DHCP server to acquire network parameters is described.

JP 2004-104199 A

  In the present invention, when a setting information group including an IP address of a default gateway connected via a router is provided, communication using the setting information group is performed and communication via the default gateway is performed. With the goal.

According to a first aspect of the present invention, there is provided a communication device that broadcasts request data for requesting a setting information group used for communication, and an IP (Internet Protocol) address of a router connected to the first communication line. Used for communication to the first communication line when the address specifying means to be specified and the router are set to transfer the request data transmitted by the transmission means to the first communication line A gateway device connected to the first communication line from a first setting information providing device that provides the first setting information group, the gateway device being connected to the own device via the router, and a default gateway the first setting information group the IP address of the gateway apparatus having a function of its own apparatus comprises as the IP address of the default gateway for use in communication A first setting acquiring means for acquiring via the router, the first setting information an IP address its own apparatus included in the group of IP address of the default gateway for use in communication, IP address of the gateway device from communicates to the first communication line by using the changing means for changing the IP address of the address specifying means has specified the first setting information group before Symbol changes are made by the changing means, The communication apparatus includes an external device connected via the router and a communication unit that communicates using the IP address of the router.

  According to a second aspect of the present invention, in the communication device according to the first aspect, the address specifying unit uses a MAC address added to the setting information group acquired by the first setting acquiring unit. The IP address assigned to the interface identified by the MAC address is acquired, and the acquired IP address is specified as the IP address of the router.

  According to a third aspect of the present invention, in the communication device according to the second aspect, the address specifying means acquires the IP address from the MAC address using RARP (Reverse Address Resolution Protocol), and The acquired IP address is specified as the IP address of the router.

  According to a fourth aspect of the present invention, there is provided the communication apparatus according to any one of the first to third aspects, wherein the second setting used for communication to the second communication line to which the router is connected. A second setting acquisition unit configured to acquire a predetermined type of the second setting information group from the second setting information providing device that provides the information group via the second communication line; The means performs communication to the second communication line using the second setting information group acquired by the second setting acquisition means.

  In the communication device according to claim 5 of the present invention, in the configuration according to claim 4, the second setting acquisition unit acquires an IP address of the second setting information providing device, and the acquired IP address The request data for requesting the second type of setting information of the predetermined type is transmitted to the destination, and the second setting information group is obtained from the second setting information providing apparatus that has received the request data. It is characterized by doing.

  The communication device according to claim 6 of the present invention is the communication device according to claim 4 or 5, wherein the second setting information providing device is a DHCP (Dynamic Host Configuration Protocol) server device, and the second setting acquisition The means is characterized in that the second setting information group is acquired using DHCPINFORM, which is data requesting a predetermined type of setting information group other than the IP address.

A communication apparatus according to claim 7 of the present invention is the configuration according to any one of claims 1 to 3, wherein the second setting information connected to the second communication line to which the router is connected. Request data transmitted by the transmitting means is not provided via a router to a second setting information providing apparatus that provides a setting information group used for communication to the second communication line. When connected by a route to reach, a second type of second setting information group other than the IP address is selected from the setting information group provided by the second setting information providing apparatus that has received the request data. Extracting means for extracting, wherein the communication means is extracted by the extracting means when the request data transmitted by the transmitting means is connected by a route reaching the second setting information providing apparatus via the router. Wherein the communicating with a second device using the second setting information group that was.
The communication device according to an eighth aspect of the present invention is the configuration according to any one of the first to seventh aspects, wherein the router is connected to the first communication line via the first setting information providing device. It is connected.
The communication device according to claim 9 of the present invention is the configuration according to any one of claims 1 to 8, wherein the communication unit is only provided when the router is not set to transfer ARPREQUEST. The MAC address cannot be acquired.

According to a tenth aspect of the present invention, there is provided a program for transmitting, by broadcast, request data for requesting a setting information group used for communication to a computer, and an IP (Internet Protocol) of a router connected to the first communication line. Address specifying means for specifying an address, and communication to the first communication line when the router is set to transfer the request data transmitted by the transmitting means to the first communication line A gateway device connected to the first communication line from the first setting information providing device that provides the first setting information group used in the communication, and connected to the own device via the router; including its own device's IP address of the gateway device with a function of the default gateway is the default gateway IP address for use in communication Serial first setting information group, the first set and the acquisition unit, the IP address of the default gateway used for the IP address at a the own device is a communication included in the first setting information group to get through the router and the IP address of the gateway device, the address changing means that certain means to change to the specified IP address, change by the changing means made the previous SL first set using information group the first It is characterized by functioning as a communication means for performing communication to a communication line and communicating with an external apparatus connected via the router using an IP address of the router.

According to the first, eighth , ninth , and tenth aspects of the present invention, when a setting information group including the IP address of the gateway device connected to the own device via the router as the IP address of the default gateway is provided, Communication using the set information group can be performed, and communication can be performed using the router as a default gateway.
According to the second and third aspects of the invention, even when the IP address of a router is not known, communication can be performed using the router as a default gateway.
According to the fourth and fifth aspects of the present invention, communication can be performed via the default gateway, and communication can be performed using the first setting information group and the second setting information group, respectively.
According to the sixth aspect of the present invention, when the second setting information group is a setting information group other than the IP address in the setting information group provided by the second setting information providing apparatus, a configuration not using DHCPINFORM As compared with the above, the second setting information group can be easily obtained.
According to the invention of claim 7, after the setting information group including the IP address of the gateway device connected via the router as the IP address of the default gateway is provided, the trouble of acquiring the second setting information group is reduced. Communication using the second setting information group can be performed without making a call.

It is a block diagram which shows the structure of the communication system of 1st Embodiment. 2 is a diagram illustrating a hardware configuration of an image forming apparatus. FIG. It is a figure which shows the hardware constitutions of a router. It is a sequence chart which shows the procedure of the process in a setting process. It is a table | surface which shows an example of the setting information group provided from the HGW apparatus. It is a table | surface which shows an example of the communication setting information after an IP address was changed. It is a table | surface which shows an example of the setting information group provided by the DHCP server apparatus. It is a table | surface which shows an example of the communication setting information in which the setting information group was reflected. It is a sequence chart which shows the setting process in 2nd Embodiment. It is a sequence chart which shows the setting process in 3rd Embodiment. It is a table | surface which shows an example of the setting information group provided from the DHCP server apparatus. It is a table | surface which shows an example of the communication setting information in which the setting information group was reflected. 6 is a flowchart illustrating a procedure of processing performed by the image forming apparatus. 2 is a block diagram illustrating functions realized by the image forming apparatus. FIG.

[First Embodiment]
FIG. 1 is a block diagram showing a configuration of a communication system 1 in the first embodiment of the present invention. The communication system 1 includes a public IP line 2, an intranet 3, an image forming apparatus 10, a router 20, a HGW (Home Gateway) apparatus 30, a facsimile apparatus 41, a DHCP server apparatus 51, a DNS ( Domain Name System) server device 52, WINS (Windows (registered trademark) Internet Name Service) server device 53, and user terminal 54. These devices and terminals are computers having a function of transmitting and receiving data using a TCP / IP procedure. Information for controlling communication is added to the transmitted / received data, and this information includes, for example, an IP address and a MAC address.

  The public IP line 2 and the intranet 3 are both lines on which communication using TCP / IP is performed, and are managed as different sub-networks. The public IP line 2 is assigned a private IP address of 192.168.1.0/24 (192.168.1.0 to 255), and the intranet 3 is 10.0.0.0/ A private IP address of 24 (10.0.0.0 to 255) is assigned. The subnet masks of these private IP addresses are all “255.255.255.0”. That is, the network address of the public IP line 2 is “192.168.1.0”, and the network address of the intranet 3 is “10.0.0.0”. The public IP line 2 is, for example, NGN (Next Generation Network), and the intranet 3 is, for example, a corporate LAN (Local Area Network).

  The router 20 includes a first communication I / F (interface) 201, a second communication I / F 202, and a third communication I / F 203 that serve as interfaces in communication with other computers. These communication I / Fs are called NIC (Network Interface Card) and each have a physical hardware port (referred to as “physical port”). These communication I / Fs are connected to other devices and communication lines via LAN cables inserted into the respective physical ports. Specifically, the router 20 is connected to the HGW apparatus 30 via the first communication I / F 201. That is, the router 20 is also connected to the public IP line 2 via the HGW device 30. The router 20 is connected to the intranet 3 via the second communication I / F 202. The first communication I / F 201 and the second communication I / F 202 are pre-assigned IP addresses “192.168.1.254” and “10.0.0.254”, respectively. The router 20 is connected to the image forming apparatus 10 via the third communication I / F 203. An IP address “192.168.1.253” is assigned in advance to the third communication I / F 203. The subnet mask of this IP address is 255.255.255.0. That is, the third communication I / F 203 is managed by a common subnetwork with the first communication I / F 201.

  The router 20 transfers data transmitted from a device connected to a certain subnetwork (for example, the public IP line 2) to a device connected to another subnetwork (for example, the intranet 3). A device that performs routing. The router 20 performs routing based on information included in the transmitted data. This information is, for example, a destination IP address, a source IP address, and a port number. Here, the port number is a number indicating a logical software port, and designates a partner program that receives and processes transmitted data among a plurality of programs executed by a destination computer. It is a number to do. For example, when data including a port number 5060 is transmitted, a program corresponding to SIP communication is designated as a partner for processing the data. The router 20 determines a transfer destination device based on these pieces of information, and transfers data to the device. The router 20 holds data for determining a transfer destination device from these pieces of information (what is called a routing table and a route map). This data is data indicating routing settings, and is hereinafter referred to as “routing setting data”.

  In the routing setting data, for example, the network address of the transmission destination and the IP address of the transfer destination device are shown in association with each other. For example, the IP address of the HGW device 30 is associated with the network address (192.168.1.0) of the public IP line 2 because the transfer destination device is the HGW device 30. Thereby, for example, when the network address of the transmission destination included in the transmitted data is 192.168.1.0, the router 20 transfers the data to the HGW device 30.

  Further, in the routing setting data, for example, a source IP address and a transfer destination device are associated with each other, or a port number and a transfer destination device are associated with each other. Thereby, when the IP address and the port number of the transmission source included in the transmitted data are associated with the transfer destination in the routing setting data, the router 20 transfers the data to the transfer destination. If the data is transferred and not associated, routing is performed such that the data is discarded without being transferred anywhere.

  The router 20 is set not to transfer data (referred to as an ARP packet) transmitted based on a procedure called ARP (Address Resolution Protocol) for obtaining a destination MAC address from a destination IP address. The destination MAC address is information necessary for transmitting data to the destination. For this reason, even if a computer connected to a certain subnetwork (for example, intranet 3) attempts to transmit data to a computer connected to another subnetwork (for example, public IP line 2), the destination MAC address cannot be acquired. , The destination MAC address cannot be included in the transmitted data, and the data cannot reach the destination. In this way, when communication across different sub-networks is performed, the router 20 has a function as a so-called default gateway that relays the communication. For example, a computer that communicates directly with the router 20, that is, a transmitted ARP packet reaches the router 20 without passing through another router, uses the router 20 as the default gateway IP address (default gateway address). Set the IP address. This computer acquires the MAC address of the router 20 from the IP address of the router 20 by performing processing according to the ARP procedure. This computer transmits data including the acquired MAC address of the router 20 and the destination IP address to the router 20. The router 20 transfers the received data to a device corresponding to the network address indicated by the destination IP address.

  The DHCP server device 51 is a device having a function as a so-called DHCP server that provides a setting information group used for communication to other computers using a procedure called DHCP. This function is used when a computer tries to connect to a communication line such as the public IP line 2 or the intranet 3, and the IP address and subnet mask used when communicating with other computers via the communication line. A plurality of setting information (setting information group) is provided to those computers. Communication performed in this procedure is called DHCP communication. The DHCP server device 51 has a communication I / F 511 and is connected to the intranet 3 via the communication I / F 511. An IP address “10.0.0.3” is assigned in advance to the communication I / F 511. Hereinafter, in a computer having only one communication I / F, such as the DHCP server device 51, the IP address assigned to the communication I / F is also referred to as the IP address of the computer.

  The DNS server device 52 specifies a IP address of a computer identified by the domain name from a name functioning as an identifier for identifying each computer called a domain name (so-called domain name resolution is performed). As a function. The DNS server device 52 has a communication I / F 521, and is connected to the intranet 3 via the communication I / F 521. An IP address “10.0.0.1” is assigned in advance to the communication I / F 521.

  The WINS server device 53 specifies a computer IP address identified by the computer name from a name functioning as an identifier for identifying each computer called a computer name (so-called computer name resolution). As a function. The WINS server device 53 has a communication I / F 531 and is connected to the intranet 3 via the communication I / F 531. An IP address “10.0.0.2” is assigned in advance to the communication I / F 531.

  The user terminal 54 is a personal computer, for example, and is a terminal used by a user who uses the image forming apparatus 10. The user terminal 54 is connected to the intranet 3. The user terminal 54 is operated by a user to display image data indicating an image, data requesting to transmit the image data by facsimile communication, data requesting to form an image indicated by the image data, and the like. And transmitted to the image forming apparatus 10 via the intranet 3.

  The HGW apparatus 30 includes a first communication I / F 301 and a second communication I / F 302, is connected to the router 20 via the first communication I / F 301, and is connected to the public IP line 2 via the second communication I / F 302. Connected with. The first communication I / F 301 is assigned an IP address “192.168.1.1”. The HGW apparatus 30 is a DHCP server apparatus having a function as the above-described DHCP server. The HGW apparatus 30 also has the above-described function as a DNS server and the function as a default gateway.

  The facsimile apparatus 41 is an apparatus having the above-described facsimile function, that is, an IP fax function corresponding to SIP communication. The facsimile apparatus 41 is connected to the public IP line 2 and performs facsimile communication with the image forming apparatus 10 via the public IP line 2, the HGW apparatus 30 and the router 20.

  The image forming apparatus 10 includes a communication I / F 110 and is connected to the third communication I / F 203 of the router 20 via the communication I / F 110. The image forming apparatus 10 has an image forming function for forming an image on a recording medium such as paper using image data indicating the image, and a scanning function for reading the image formed on the recording medium and generating image data indicating the image. And a facsimile function for transmitting and receiving image data by facsimile communication. This facsimile function includes an IP fax function compatible with SIP (Session Initiation Protocol) communication. The image forming apparatus 10 executes these functions by communicating with other computers via the router 20, the public IP line 2, and the intranet 3. For example, the image forming apparatus 10 receives image data transmitted from the user terminal 54 via the intranet 3 and data for requesting transmission or image formation in the above-described facsimile communication, whereby an image forming function or a facsimile is received. Perform the function. Further, the image forming apparatus 10 transmits the image data generated by executing the scan function and the image data received by executing the facsimile function to the user terminal 54 via the intranet 3.

  The image forming apparatus 10 acquires information used when performing these communications from the DHCP server devices (the HGW device 30 and the DHCP server device 51) described above. The image forming apparatus 10 retains the acquired information as information indicating communication settings of the apparatus, and refers to the information when performing communication. Information used when the image forming apparatus 10 performs communication in this way is hereinafter referred to as “communication setting information”.

  FIG. 2 is a diagram illustrating a hardware configuration of the image forming apparatus 10. The image forming apparatus 10 includes a communication I / F 110, a control unit 120, an operation unit 130, a display unit 140, a storage unit 150, and an image forming unit 160. The control unit 120 includes an arithmetic device including a CPU (Central Processing Unit) and a memory. The arithmetic unit of the control unit 120 executes a program stored in the memory to control each unit of the image forming apparatus 10 and process data. The control unit 120 has a function of measuring time, acquires the time when these controls and processes are performed, and performs these controls and processes at a predetermined time.

  The communication I / F 110 communicates with a computer other than its own device, for example, the facsimile apparatus 41 and the user terminal 54 via the router 20 as described above. For example, the above-described image data and request data are transmitted from the user terminal 54 to the communication I / F 110. The communication I / F 110 supplies the transmitted data to the control unit 120.

  The operation unit 130 includes an operation element such as a button, and supplies operation information representing the operation content to the control unit 120 according to a user operation. The display unit 140 includes a liquid crystal display screen and a liquid crystal drive circuit, and displays the progress of processing, information for guiding operations to the user, and the like based on information supplied from the control unit 120. The storage unit 150 includes a storage device such as an HDD (Hard Disk Drive), and stores, for example, the communication setting information and the image data. The image forming unit 160 is a unit that forms an image on a sheet. For example, the image forming unit 160 uses four color toners of yellow (Y), magenta (M), cyan (C), and black (K) to form a sheet by electrophotography. An image is formed on. For example, when a facsimile function or an image forming function is executed, the image forming unit 160 forms an image indicated by the image data on a recording medium (that is, outputs the image data).

  FIG. 3 is a diagram illustrating a hardware configuration of the router 20. The router 20 includes a control unit 210, a first communication I / F 201, a second communication I / F 202, a third communication I / F 203, and a storage unit 220. The control unit 210 includes an arithmetic device such as a CPU and a storage device such as a ROM and a RAM. The CPU controls the operation of each unit of the router 20 by executing a program stored in the ROM or the storage unit 220 using the RAM as a work area. As described above, the first communication I / F 201, the second communication I / F 202, and the third communication I / F 203 are connected to other devices and communication lines, respectively. The storage unit 220 is a storage unit such as a hard disk, and stores data and programs used by the control unit 210 for control. The storage unit 220 stores the above-described routing setting data.

  The image forming apparatus 10 provides the above-described image forming function and facsimile function to, for example, the user terminal 54 by providing the above configuration. While the image forming apparatus 10 communicates with the user terminal 54 via the intranet 3, the image forming apparatus 10 communicates with the facsimile apparatus 41 via the HGW apparatus 30 and the public IP line 2 to provide these functions to the user terminal 54. It has become. In order to perform these communications, the image forming apparatus 10 acquires a setting information group used for communication from the HGW apparatus 30 and the DHCP server apparatus 51 having a function as a DHCP server, and reflects it as communication setting information of the own apparatus. Perform the setting process. Hereinafter, the setting process according to the first embodiment will be described with reference to FIGS. 4 to 6.

  FIG. 4 is a sequence chart illustrating a procedure of processes performed by each device in the setting process according to the first embodiment. This setting process is started when the image forming apparatus 10 is turned on (step S11). In the image forming apparatus 10, in order to perform this setting process, the operation performed by the user before the start of the setting process in step S11, that is, before the last power-off. Based on the operation information supplied from the unit 130, the IP addresses of the router 20 and the DHCP server device 51 are stored in advance in the storage unit 150 (step S1). The IP address of the router 20 stored at this time is a communication I / F that can be used as a DGW (default gateway) address as viewed from the image forming apparatus 10, that is, the first ARP packet transmitted from the image forming apparatus 10 arrives. 3 is the IP address “192.168.1.253” assigned to the communication I / F 203.

  After the processing in step S11 is performed, the image forming apparatus 10 broadcasts data called DHCPDISCOVER requesting to provide a setting information group used for communication to a device having a DHCP server function (step S11). S12). This data includes 67 as the port number on the DHCP server apparatus side and 68 as the port number on the DHCP client (a computer requesting the setting information group, in this case, the image forming apparatus 10) side.

  In the router 20, when the port number 67 (or 68) is included in the packet transmitted in advance via the first communication I / F 201 and the third communication I / F 203 in advance, the communication I / F (the first communication I / F 201 is the third communication I / F 203, and the third communication I / F 203 is the first communication I / F 201). Routing setting data is stored in the storage unit 220. With this routing setting data, DHCP communication via the first communication I / F 201 and the third communication I / F 203 is performed. For example, since the DHCPDISCOVER transmitted in step S12 includes 67 as the destination port number (or 68 as the transmission source port number), the router 20 determines whether the router 20 is based on the setting indicated by the routing setting data. This DHCPDISCOVER is transmitted by broadcast via one communication I / F 201. The DHCPDISCOVER transmitted in step S12 thus reaches the HGW device 30 via the router 20.

  When receiving the DHCPDISCOVER transmitted in step S12, the HGW device 30 broadcasts data called DHCPOFFER indicating a predetermined type of setting information group (IP address, etc.) to be presented to the data request source. Transmit (step S13). The DHCPOFFER transmitted in step S13 reaches the router 20. Based on the routing setting data, the router 20 transmits the received DHCPOFFER via the third communication I / F 203 by broadcast. The DHCPOFFER transmitted in step S13 thus reaches the image forming apparatus 10 via the router 20.

  The image forming apparatus 10 broadcasts data called DHCPREQUEST indicating that the setting information group indicated by DHCPOFFER received in step S13 is formally requested (step S14). The DHCPREQUEST transmitted in step S14 reaches the HGW device 30 via the router 20. Upon receiving DHCPREQUEST in step S14, the HGW device 30 recognizes the request indicated by this data (for example, when the presented IP address is not yet assigned to another interface), and DHCPACK indicating the setting information group presented by DHCPOFFER. Is transmitted by broadcast (step S15). The DHCPACK transmitted in step S15 reaches the image forming apparatus 10 via the router 20. The image forming apparatus 10 reflects the setting information group indicated by DHCPACK transmitted in step S15, that is, the setting information group provided by the HGW apparatus 30, as the communication setting information of the own apparatus (step S16).

  FIG. 5 is a table showing an example of the setting information group provided by the HGW apparatus 30. In this table, the content of each “type of setting information” is shown in the column of “content of provided setting information”, and specifically, the content of “IP address” is “192.168 .. 1.2 ”,“ Subnet Mask ”is“ 255.255.255.0 ”,“ Telephone Number ”is“ 03-1234-5678 ”, and“ DGW Address ”is“ 192.168.1. ” .1 ”and“ DNS server address ”are“ 192.168.1.1 ”, respectively. The HGW apparatus 30 provides, as setting information, information that is not currently used from ranges set in advance for IP addresses and telephone numbers. This telephone number indicates a destination when image data indicating an image is transmitted via the public IP line 2 by facsimile communication, and is provided as a destination when image data is transmitted to the image forming apparatus 10. It is what is done. Further, the HGW apparatus 30 provides the IP address of the own apparatus (in this example, “192.168.1.1”) as the DNS server address that is the DGW address and the IP address of the DNS server.

Next, the image forming apparatus 10 specifies the IP address of the third communication I / F 203 of the router 20 stored in the storage unit 150 as the router functioning as the default gateway, that is, the IP address of the router 20. For example, the image forming apparatus 10 stores the IP address of the router 20 in a predetermined area in step S1. As a result, even if a plurality of IP addresses are stored in the storage unit 150, the image forming apparatus 10 identifies the IP address stored in that area as the IP address of the router 20. Then, the image forming apparatus 10 changes the DGW address (that is, the IP address of the HGW apparatus 30) reflected as the communication setting information in step S16 to the specified IP address (step S17).
FIG. 6 is a table showing an example of communication setting information reflected after the process of step S17 is performed. In FIG. 6, “setting information types” common to the setting information group shown in FIG. 5 acquired in step S <b> 16 and “contents of reflected setting information” are shown for each type. Among the contents of the reflected setting information, the contents other than “DGW address” are the same as the contents of the setting information shown in FIG. 5, and “DGW address” is “192.168.1” shown in FIG. .1 ”is changed to“ 192.168.1.253 ”, which is the IP address assigned to the third communication I / F 203 of the router 20.

  When the image forming apparatus 10 performs communication via the default gateway, the image forming apparatus 10 transmits data called ARPREQUEST by broadcast to acquire a MAC address from the IP address of the default gateway. This ARPREQUEST does not reach the HGW apparatus 30 unless it passes through the router 20, but the router 20 does not transfer the ARPREQUEST unless special settings are made. For this reason, when the IP address of the HGW apparatus 30 is set as the default gateway address, the image forming apparatus 10 cannot perform communication via the default gateway. According to this embodiment, in step S17, the IP address of the third communication I / F 203 of the router 20 is set as the default gateway address. The router 20 is a router connected to the image forming apparatus 10. In other words, the router 20 is a router from which the image forming apparatus 10 can acquire a MAC address. For this reason, the image forming apparatus 10 communicates using the router 20 as a default gateway, thereby preventing a situation in which communication via the default gateway cannot be performed.

  Next, the image forming apparatus 10 defaults data requesting a predetermined set information group other than the IP address called DHCPINFORM to the IP address of the DHCP server apparatus 51 stored in the storage unit 150 in step S1. It transmits to the router 20 which is a gateway (step S18). In this example, a DNS server address and a WINS server address are determined in advance as a set information group required by DHCPINFORM. When the router 20 receives the DHCPINFORM in step S18, the router 20 broadcasts an ARP including the IP address that is the destination of this data, acquires the MAC address of the DHCP server device 51, and sends this data to the DHCP server device 51. Transfer (step S19). When the DHCP server device 51 receives DHCPINFORM in step S19, the DHCP server device indicates DHCPACK indicating a predetermined set information group (ie, DNS server address and WINS server address) other than the above-described IP address via the router 20. 10 (step S20). The image forming apparatus 10 receives the DHCPACK transmitted in step S20, and acquires the setting information group indicated by this data. As described above, the image forming apparatus 10 acquires the setting information group from the DHCP server apparatus 51 using DHCPINFORM.

  FIG. 7 is a table showing an example of the setting information group acquired by the image forming apparatus 10 in step S20 (that is, provided by the DHCP server apparatus 51). This table indicates that the contents of “DNS server address” are “10.0.0.1” and the contents of “WINS server address” are “10.0.0.2”, respectively. As shown in FIG. 7, the DHCP server device 51 provides the IP address of the DNS server device 52 as a “DNS server address” and the IP address of the WINS server device 53 as a “WINS server address”.

Then, the image forming apparatus 10 reflects the setting information group acquired in step S20 in the communication setting information stored in the storage unit 150 (step S21).
FIG. 8 is a table showing an example of communication setting information in which the setting information group is reflected in step S21. In this table, the contents of “IP address”, “subnet mask”, and “telephone number” are the same as those shown in FIG. Since these setting information groups are the types of setting information not acquired in step S20, they do not change even if the process of step S20 is performed. In this table, the contents of “DNS server address” and “WINS server address” are the same as those shown in FIG. That is, the image forming apparatus 10 overwrites the “DNS server address” with the one acquired in step S20. Since the “WINS server address” is the type of setting information that has not been acquired in step S15, the image forming apparatus 10 adds this to the communication setting information. As a result, the image forming apparatus 10 communicates with, for example, the facsimile apparatus 41 using the IP address and the telephone number, which are setting information provided from the HGW apparatus 30, and the setting information provided from the DHCP server apparatus 51. For example, communication with the user terminal 54 is performed using a certain DNS server address and WINS server address.

[Second Embodiment]
The communication system according to the second embodiment of the present invention is different from the first embodiment in that the image forming apparatus 10 acquires the IP address of the third communication I / F 203 of the router 20. In the first embodiment, the image forming apparatus 10 acquires this IP address by operating the operation unit 130 by a user. In this embodiment, the image forming apparatus 10 acquires this IP address by communicating with the router 20.
FIG. 9 is a sequence chart showing a setting process in the second embodiment. The communication system according to this embodiment has the same hardware configuration as that of the first embodiment. The image forming apparatus 10 stores the IP address of the DHCP server device 51 in the storage unit 150 in advance based on operation information supplied from the operation unit 130 operated by the user instead of step S1 illustrated in FIG. (Step S2). That is, in step S2, the IP address of the third communication I / F 203 of the router 20 is not stored.

  Subsequently, the image forming apparatus 10 performs the processing from steps S11 to S16 illustrated in FIG. 4 and reflects the setting information group acquired from the HGW apparatus 30 as communication setting information. Next, the image forming apparatus 10 obtains the IP address of the third communication I / F 203 of the router 20 using a procedure called RARP (Reverse Address Resolution Protocol) for obtaining the destination IP address from the destination MAC address. get. The DHCPACK received by the image forming apparatus 10 in step S15 includes the MAC address of the transmission source, that is, the third communication I / F 203 of the router 20. The image forming apparatus 10 includes this MAC address in data requesting an IP address based on the RARP procedure (referred to as a RARP request packet) and transmits it to the router 20 (step S31).

  When the router 20 receives the RARP request packet transmitted in step S31 via the third communication I / F 203, the router 20 converts the data for responding to this based on the RARP procedure (referred to as the RARP response packet) into the third The IP address assigned to the communication I / F 203 is transmitted to the image forming apparatus 10 (step S32). The image forming apparatus 10 receives the RARP response packet transmitted in step S32, and acquires the IP address of the third communication I / F 203 of the router 20 included in this packet. Then, the image forming apparatus 10 identifies the acquired IP address as an IP address of a router that functions as a default gateway, that is, the router 20. Then, the image forming apparatus 10 changes the DGW address reflected as the communication setting information in step S16 to the specified IP address (step S33). As a result, the image forming apparatus 10 performs communication using the router 20 as a default gateway.

[Third Embodiment]
The communication system according to the third embodiment of the present invention is different from the first and second embodiments in the method by which the image forming apparatus 10 acquires the IP address of the DHCP server device 51. In the first and second embodiments, the image forming apparatus 10 obtains this IP address by operating the operation unit 130 by a user. However, in the present embodiment, this IP address is obtained by communicating with the DHCP server apparatus 51. Get the address.
FIG. 10 is a sequence chart showing the setting process in the third embodiment. In the present embodiment, the processing from steps S11 to S17 shown in FIG. 4 is performed with the same configuration as the communication system 1 of the first embodiment, but before that, the processing of step S3 and the processing of steps S41 to S45 are performed. And done. The processes from steps S41 to S45 are performed when the image forming apparatus 10 is connected to the intranet 3 instead of the router 20.

  The image forming apparatus 10 first stores the IP address (192.168.1.253) of the third communication I / F 203 of the router 20 in advance based on the operation information supplied from the operation unit 130 operated by the user. 150 (step S3). Thereafter, when the power is turned off and the power is turned on again (step S41), the image forming apparatus 10 transmits DHCPDISCOVER by broadcast (step S42). At this time, since the image forming apparatus 10 is connected to the intranet 3 as described above, the DHCPDISCOVER reaches the DHCP server apparatus 51 via the intranet 3. Upon receiving DHCPDISCOVER, the DHCP server device 51 broadcasts DHCPOFFER according to the DHCP procedure (step S43). This DHCPOFFER reaches the image forming apparatus 10 via the intranet 3. By receiving this DHCPOFFER, the image forming apparatus 10 acquires a setting information group indicated by this data.

  FIG. 11 is a table showing an example of the setting information group acquired by the image forming apparatus 10 in step S43 (that is, provided by the DHCP server apparatus 51). In this table, the content of “IP address” is “10.0.0.5”, the content of “subnet mask” is “255.255.255.0”, and the content of “DGW address” is “10.0.0.5”. 0.254 ”and“ DNS server address ”are“ 10.0.0.1 ”and“ WINS server address ”is“ 10.0.0.2 ”. The image forming apparatus 10 determines whether or not the setting information group includes predetermined specific setting information. The predetermined specific setting information is, for example, a telephone number. As shown in FIG. 11, when the acquired setting information group does not include a telephone number, the image forming apparatus 10 does not transmit DHCPREQUEST by broadcast, and predetermined setting information is selected from these setting information groups. Is stored in the storage unit 150 (step S44). The predetermined setting information is a DNS server address and a WINS server address.

  In the image forming apparatus 10, after step S 44, the LAN cable connected to the communication I / F 110 is reconnected (step S 45), and the router is connected to the intranet 3 as shown in FIG. 20 is connected. Thereafter, the processing from steps S11 to S17 shown in FIG. 4 is performed, and the image forming apparatus 10 reflects the setting information group acquired from the HGW apparatus 30 as communication setting information, and the DGW address of the setting information group is the third address of the router 20. The IP address of the communication I / F 203 is changed to 192.168.1.253. Thereby, the setting information group shown in FIG. 6 is reflected as the communication setting information. Then, the image forming apparatus 10 reflects the setting information (DNS server address and WINS server address) stored in step S44 as communication setting information (step S46).

  FIG. 12 is a table showing an example of communication setting information in which the setting information is reflected in step S46. In this table, “DNS server address” is changed from “192.168.1.1” shown in FIG. 6 to “10.0.0.1”, and is included in the communication setting information shown in FIG. The setting information “WINS server address” and “10.0.0.2” that have not been added are added. As a result, communication setting information common to that shown in FIG. 8 is reflected, and the image forming apparatus 10 communicates with the facsimile apparatus 41 and the user terminal 54 as described above. Further, according to the present embodiment, after the setting information group is provided from the HGW device 30, the DNS server address and the WINS server address are used without taking the trouble of acquiring the setting information group from the DHCP server device 51. Communication will take place.

[Summary of each embodiment]
In each of the above-described embodiments, the image forming apparatus 10 performs processing according to the following procedure.
FIG. 13 is a flowchart illustrating a procedure of processing executed by the image forming apparatus 10. First, when the power is turned on, the image forming apparatus 10 broadcasts DHCPDISCOVER to acquire a setting information group (step S101). This process is executed in step S12 shown in FIG. 4 and the like and step S42 shown in FIG. Next, the image forming apparatus 10 determines whether the setting information group acquired in step S101 includes a telephone number as specific information determined in advance (step S102). When determining that the telephone number is not included (NO), the image forming apparatus 10 broadcasts DHCPREQUEST and determines whether or not DHCPACK is received (step S103). If it is determined that it has been received (YES), the image forming apparatus 10 reflects the setting information group indicated by the received DHCPACK as communication setting information (step S104). For example, when DHCPACK is not received even after a predetermined time has elapsed, the image forming apparatus 10 determines that it does not receive (NO), and notifies the user that the communication setting information is not reflected ( Step S105), the setting process ends.

  If the image forming apparatus 10 determines in step S102 that the acquired setting information group includes a telephone number that is a specific setting information group (YES), the image forming apparatus 10 reflects these setting information groups as communication setting information. (Step S111). This is a process common to step S16 shown in FIG. Subsequently, the image forming apparatus 10 determines whether or not the IP address of the DGW address (for example, the IP address of the third communication I / F 203 of the router 20) is stored (step S112). If NO is determined, the IP address is acquired by the ARP procedure (step S113). This is a process common to steps S31 and S32 shown in FIG. When NO is determined in step S112, the image forming apparatus 10 performs a process common to step S17 shown in FIG. 4 and the like, and when the process of step S113 is performed, the image forming apparatus 10 performs a process common to step S33 shown in FIG. . As a result, the image forming apparatus 10 changes the DGW address to the IP address of the third communication I / F 203 of the router 20 (step S114).

  Subsequently, the image forming apparatus 10 determines whether or not other predetermined setting information is stored in the storage unit 150 (step S115). For example, when the processing from step S41 to S45 shown in FIG. 10 is performed, this setting information is stored. In this case (step S115: YES), the image forming apparatus 10 reflects the stored setting information in the communication setting information (step S119), and ends the setting process. On the other hand, if it is determined in step S115 that the setting information is not stored (NO), the image forming apparatus 10 determines whether or not the IP address of the DHCP server device 51 is stored in the storage unit 150 (step S116). ). If the image forming apparatus 10 determines that this IP address is not stored (step S116: NO), it performs the process of step S105 and ends the setting process. When the process of step S1 shown in FIG. 4 or step S2 shown in FIG. 9 has already been performed, the image forming apparatus 10 determines that this IP address is stored (step S116: YES), and FIG. The processing of step S18 shown in FIG. 6 is performed to request predetermined setting information from the DHCP server device 51 (step S117). Then, the image forming apparatus 10 determines whether or not setting information has been acquired (step S118). If it is determined that the setting information has been acquired (YES), the acquired setting information is reflected as communication setting information (step S119). . In step S118, for example, if the setting information is not obtained within a predetermined time, the image forming apparatus 10 determines that the setting information has not been acquired (NO), and executes the process of step S105 to perform the setting process. Exit.

In each of the above-described embodiments, the image forming apparatus 10 realizes the following functions by the control unit 120 executing a program to control each unit.
FIG. 14 is a functional block diagram illustrating functions realized by the image forming apparatus 10. The image forming apparatus 10 includes a transmission unit 101, a first setting acquisition unit 102, an address specification unit 103, a change unit 104, a communication unit 105, a second setting acquisition unit 106, and an extraction unit 107. Prepare. The transmission unit 101 broadcasts request data (for example, DHCPDISCOVER) for requesting the setting information group illustrated in FIGS. 5 and 6 by performing the process of step S12 illustrated in FIG. 4 and the like. The transmission unit 101 is a function realized by the control unit 120 and the communication I / F 110 shown in FIG. 2 in cooperation, and is an example of the “transmission unit” according to the present invention.

  When the router 20 is set to transfer DHCPDISCOVER to the public IP line 2, the first setting acquisition unit 102 performs setting information from the HGW device 30 by performing the process of step S <b> 14 illustrated in FIG. 4 and the like. A group (hereinafter referred to as “first setting information group”) is acquired via the public IP line 2. This router 20 is a router to which DHCPDISCOVER transmitted by the transmission unit 101 arrives without passing through another router. In addition, the first setting information group includes the IP address of the HGW device 30 as the DGW address. This HGW apparatus 30 is an example of a “default gateway” according to the present invention. The HGW device 30 is a device that provides a first setting information group used for communication to the public IP line 2 (for example, communication with the facsimile apparatus 41 connected to the public IP line 2). This is an example of a “first setting information providing device”. The public IP line 2 is an example of the “first communication line” according to the present invention. The first setting acquisition unit 102 supplies data indicating the acquired first setting information group to the change unit 104 and the communication unit 105. The first setting acquisition unit 102 is a function realized by the control unit 120 and the communication I / F 110 illustrated in FIG. 2 in cooperation with each other, and is an example of the “first setting acquisition unit” according to the present invention.

  The address specifying unit 103 is a unit for specifying the IP address of the default gateway connected to the transmitting unit 101 without going through the router, that is, the router 20 shown in FIG. This IP address is an IP address assigned to the third communication I / F 203 of the router 20. Since this router 20 is connected to the image forming apparatus 10 without passing through another router, the ARP packet transmitted by the image forming apparatus 10 by broadcast is arrived even if the routing is not particularly set. It has become. That is, the router 20 is a default gateway from which the image forming apparatus 10 can obtain a MAC address, and is also an example of a “router” according to the present invention. The address specifying unit 103 supplies data indicating the specified IP address to the changing unit 104. If the address specifying unit 103 is the first and third embodiments described above, the control unit 120, the operation unit 130, and the storage unit 150 illustrated in FIG. This is a function realized by performing the process of step S3. In the second embodiment, the function realized by the process of step S2 shown in FIG. 9 in cooperation with the control unit 120 and the communication I / F 110. It is. The address specifying unit 103 is an example of the “address specifying unit” according to the present invention.

The changing unit 104 changes the IP address included in the setting information group acquired by the first setting acquiring unit 102 to the IP address specified by the address specifying unit 103 by performing the process of step S17 illustrated in FIG. This is an example of the “changing means” according to the present invention. The change unit 104 supplies data indicating the changed IP address to the communication unit 105.
The communication unit 105 performs communication to the public IP line 2 using the first setting information group acquired by the first setting acquisition unit 102 after the change by the changing unit 104, and functions as a default gateway Communicate with an external device (for example, the user terminal 54) connected via the router 20 using the IP address of the third communication I / F 203 of the router 20. The communication unit 105 is a function realized by the control unit 120, the communication I / F 110, and the storage unit 150 shown in FIG. 2 in cooperation, and is an example of the “communication unit” according to the present invention.

  The second setting acquisition unit 106 performs processing such as step S1 shown in FIG. 4, step S2 shown in FIG. 9, step S42 shown in FIG. 10, and the like, so that the intranet 3 to which the router 20 is connected (in the present invention). The IP address of the DHCP server device 51 connected to (an example of the “second communication line”) is acquired. The DHCP server device 51 provides a setting information group used for communication with the user terminal 54 connected to the intranet 3, and is an example of the “second setting information providing device” according to the present invention. Next, the second setting acquisition unit 106 performs the process of step S18 shown in FIG. 4 and the like, and sets the predetermined type of setting information group (hereinafter “second setting”) with the acquired IP address as the destination. DHCPINFORM, which is request data for requesting "information group") is transmitted. Then, the second setting acquisition unit 106 acquires the second setting information group from the DHCP server device 51 that has received the request data. The second setting information group is the DGW address, DNS server address, and WINS server address shown in FIG. 7 in each of the above-described embodiments. The second setting acquisition unit 106 is a function realized by cooperation of the communication I / F 110, the control unit 120, and the operation unit 130 illustrated in FIG. 2, and is an example of the “second setting acquisition unit” according to the present invention. It is. The second setting acquisition unit 106 supplies data indicating the acquired second setting information group to the communication unit 105. In this case, the communication unit 105 performs communication (for example, communication with the user terminal 54) to the intranet 3 using the second setting information group acquired by the second setting acquisition unit 106.

  The extraction unit 107 is connected by a route through which DHCPDISCOVER transmitted by the transmission unit 101 reaches the DHCP server device 51 without passing through the router, as in the case where the processing from steps S41 to S44 shown in FIG. 10 is performed. If there is, the second setting information group is extracted from the setting information group provided by the DHCP server device 51 that has received this data. The extraction unit 107 performs the above-described extraction by performing the process of step S <b> 44, and supplies data indicating the extracted second setting information group to the communication unit 105. The extraction unit 107 is a function realized by the control unit 120 and is an example of an “extraction unit” according to the present invention. Next, the communication unit 105 performs the process of step S45, for example, and when the DHCPDISCOVER transmitted by the transmission unit 101 is connected by a route reaching the DHCP server device 51 via the router, the extraction unit 107 For example, communication with the user terminal 54 is performed using the second setting information group extracted by.

[Modification]
Each embodiment mentioned above is only an example of implementation of the present invention, and may be changed variously as follows. Moreover, you may combine each embodiment mentioned above and each following modification as needed.

(Modification 1)
The image forming apparatus 10 reflects the setting information group acquired from the HGW apparatus 30 as communication setting information, and ends the processing shown in FIGS. 4, 9, and 10 when the DGW address is changed. Also good. For example, the image forming apparatus 10 ends the process illustrated in FIG. 4 in step S17. In this case, in the image forming apparatus 10, the setting information group shown in FIG. 6 is reflected as the communication setting information. As a result, the image forming apparatus 10 communicates with, for example, the facsimile apparatus 41 using the reflected IP address or telephone number, and with the user terminal 54 via the router 20 using the reflected DGW server address. Will communicate. That is, also in this modification, the image forming apparatus 10 uses the setting information group when the setting information group including the IP address of the HGW apparatus 30 that is the default gateway connected via the router 20 is provided. And communication via the router 20 as a default gateway.

(Modification 2)
The HGW device 30 and the DHCP server device 51 may provide the setting information group using a procedure other than DHCP. These devices may use, for example, the above-described ARP procedure or a procedure called BOOTP (Bootstrap Protocol). In short, these apparatuses are setting information providing apparatuses that provide the image forming apparatus 10 with a setting information group for communicating with the facsimile apparatus 41, the DNS server apparatus 52, the WINS server apparatus 53, the user terminal 54, and the like shown in FIG. It only needs to be functional.

(Modification 3)
In the above-described embodiment, the communication system includes the two DHCP server devices, the HGW device 30 and the DHCP server device 51, but may include three or more DHCP server devices. For example, this is a case where two DHCP server devices are connected to the intranet 3. When both of the two DHCP server apparatuses provide the above-described second setting information group, the image forming apparatus 10 may, for example, provide the second setting information group from both apparatuses. The setting information extracted from the previously provided one is overwritten with the setting information extracted from the one provided later. Note that the image forming apparatus 10 may discard what was extracted later without overwriting, or is the type of setting information included in the setting information group acquired later common to what was acquired earlier? It is possible to determine whether or not to perform the extraction and, if they are common, the extraction may not be performed.

(Modification 4)
In each of the above-described embodiments, the image forming apparatus has a facsimile function including an image forming function, a scan function, and an IP fax function, but other functions (for example, an image formed on a recording medium can be transferred to another recording medium). A copy function for copying to the other), or on the contrary, any of these functions may not be provided. In any case, the image forming apparatus includes a function provided by communication with a computer connected to the public IP line 2 such as an IP fax function, and an intranet 3 such as an image forming function and a scan function. It is preferable that at least two functions provided by communicating with a computer connected to the computer are provided. When these functions are, for example, a facsimile function and a scan function, the image forming apparatus may not include the image forming unit 160. In either case, the image forming apparatus only needs to function as a communication apparatus that performs the two types of communication described in this modification.

(Modification 5)
In each of the above-described embodiments, the router 20 forwards DHCPDISCOVER and DHCPREQUEST transmitted by broadcast in steps S12 and S14 illustrated in FIG. 4 and the like toward the HGW apparatus 30 based on the setting indicated by the routing setting data. However, this transfer may be performed using a program called a DHCP relay agent. The DHCP relay agent is a program for realizing a function of transferring these data transmitted by broadcast to another subnetwork. In this case, the router 20 stores the IP address of the HGW device 30 in advance, and transfers the received DHCPDISCOVER and DHCPREQUEST to the stored IP address. Thereby, the processing from step S12 to S15 shown in FIG. 4 and the like is performed, and the image forming apparatus 10 acquires the setting information group from the HGW apparatus 30.

(Modification 6)
The image forming apparatus 10 may acquire a setting information group including a DGW address in step S20 illustrated in FIG. In this case, the image forming apparatus 10 reflects the setting information other than the DGW address in the acquired setting information group, and does not reflect the DGW address. As a result, a situation in which the image forming apparatus 10 cannot communicate via the default gateway is prevented.

(Modification 7)
In the above-described embodiment, the third communication I / F 203 of the router 20 is assigned in advance an IP address (that is, 192.168.1.253) that is common to the first communication I / F 201 and the subnetwork. An IP address common to the second communication I / F 202 and the sub-network (for example, 10.0.0.253. The subnet mask is 255.255.255.0) may be allocated in advance. Also in this case, the router 20 stores the routing setting data set so that the DHCP communication is performed via the first communication I / F 201 and the third communication I / F 203 in the storage unit 220. Thereby, the processing from step S12 to S15 shown in FIG. 4 and the like is performed, and the image forming apparatus 10 acquires the setting information group shown in FIG.

(Modification 8)
In each of the above-described embodiments, the image forming apparatus 10 specifies the IP address of the router 20 in the processing of step S17 shown in FIG. 4 and the like and step S33 shown in FIG. 9, but this specification is performed before this. Also good. For example, the image forming apparatus 10 may perform this specification while the power is turned on in step S11. In this case, the image forming apparatus 10 may perform this specification before the processing from steps S12 to S16, or may perform it in parallel with these processing. In the case of the process shown in FIG. 9, the image forming apparatus 10 performs the processes of steps S31 and S32 before performing the identification.

(Modification 9)
The present invention includes, in addition to the communication system 1 and the image forming apparatus 10, a communication apparatus (an example of the image forming apparatus 10) that executes the processes shown in FIGS. 4, 9, 10, and 13, and the communication apparatus. The present invention is also understood as a program for causing a computer called a communication system and its communication device to execute these processes. This program is provided in the form of a recording medium such as an optical disk storing the program, or downloaded in a computer via a communication line such as the Internet, and installed and made available for use. It may be a thing to do.

DESCRIPTION OF SYMBOLS 1 ... Communication system, 2 ... Public IP line, 3 ... Intranet, 10 ... Image forming apparatus, 20 ... Router, 30 ... HGW apparatus, 41 ... Facsimile apparatus, 51 ... DHCP server apparatus, 52 ... DNS server apparatus, 53 ... WINS Server device 54... User terminal 120 120 210 Control unit 110 511 521 531 Communication I / F 130 Operation unit 150 220 Storage unit 201 301 First communication I / F , 202, 302 ... second communication I / F, 203 ... third communication I / F, 101 ... transmission unit, 102 ... first setting acquisition unit, 103 ... address specifying unit, 104 ... change unit, 105 ... communication unit 106 second setting acquisition unit 107 extraction unit

Claims (10)

Transmitting means for transmitting request data for requesting a set information group used for communication ;
Address specifying means for specifying an IP (Internet Protocol) address of a router connected to the first communication line;
When the router is set to transfer the request data transmitted by the transmission means to the first communication line, the first setting information group used for communication to the first communication line Of a gateway device connected to the first communication line from the first setting information providing device that provides the function, and connected to the own device via the router and having a default gateway function First setting acquisition means for acquiring, via the router , the first setting information group including an IP address as an IP address of a default gateway used by the own device for communication ;
The IP address of the default gateway used for the IP address at a the own device is a communication included in the first setting information group, from IP address of the gateway device, changing means for changing the IP address of the address specifying means has specified and,
It communicates to the first communication line by using the first setting information group before Symbol changes are made by the changing means, using the IP address of the external device and the router connected via the router And a communication means for communicating. The address specifying unit acquires an IP address assigned to an interface identified by the MAC address using a MAC address added to the setting information group acquired by the first setting acquisition unit, The communication apparatus according to claim 1, wherein the acquired IP address is specified as an IP address of the router. 3. The address specifying unit acquires the IP address from the MAC address using RARP (Reverse Address Resolution Protocol), and specifies the acquired IP address as the IP address of the router. The communication apparatus as described in. From a second setting information providing device that provides a second setting information group used for communication to a second communication line to which the router is connected, a predetermined type via the second communication line Second setting acquisition means for acquiring the second setting information group of
4. The communication device according to claim 1, wherein the communication unit performs communication to the second communication line using the second setting information group acquired by the second setting acquisition unit. 5. The communication apparatus as described in. The second setting acquisition unit acquires an IP address of the second setting information providing device, and requests the second type of setting information of the predetermined type with the acquired IP address as a destination. The communication apparatus according to claim 4, wherein the second setting information group is acquired from the second setting information providing apparatus that transmits data and receives the request data. The second setting information providing device is a DHCP (Dynamic Host Configuration Protocol) server device;
5. The second setting acquisition unit acquires the second setting information group using DHCPINFORM, which is data requesting a predetermined type of setting information group other than an IP address. Or the communication apparatus of 5. A second setting information providing apparatus connected to a second communication line to which the router is connected, and a second setting for providing a setting information group used for communication to the second communication line Provided by the second setting information providing apparatus that has received the request data when the request data transmitted by the transmission means is connected to the information providing apparatus via a route that reaches without passing through the router. Extraction means for extracting a predetermined type of second setting information group other than the IP address from the setting information group,
When the request data transmitted by the transmitting unit is connected via a route via the router to the second setting information providing device, the communication unit extracts the second setting information extracted by the extracting unit. The communication device according to claim 1, wherein the communication device communicates with the second device using a group. The router is connected to the first communication line via the first setting information providing device.
The communication device according to claim 1, wherein the communication device is a device. The communication unit cannot acquire the MAC address of the gateway device when the router is not set to transfer ARPREQUEST.
The communication apparatus according to claim 1, wherein the communication apparatus is configured as described above. Computer
Transmitting means for transmitting request data for requesting a set information group used for communication ;
Address specifying means for specifying an IP (Internet Protocol) address of a router connected to the first communication line;
When the router is set to transfer the request data transmitted by the transmission means to the first communication line, the first setting information group used for communication to the first communication line Of a gateway device connected to the first communication line from the first setting information providing device that provides the function, and connected to the own device via the router and having a default gateway function First setting acquisition means for acquiring, via the router , the first setting information group including an IP address as an IP address of a default gateway used by the own device for communication ;
The IP address of the default gateway used for the IP address at a the own device is a communication included in the first setting information group, from IP address of the gateway device, changing means for changing the IP address of the address specifying means has specified and,
It communicates to the first communication line by using the first setting information group before Symbol changes are made by the changing means, using the IP address of the external device and the router connected via the router A program for functioning as a means of communication.

Images