Information processing apparatus, control method, and program

Abstract

To allow a function using DHCP to be used at an arbitrary timing in a device operated using a fixed IP address.SOLUTION: An information processing apparatus has DHCP client processing means that executes a DHCP client function upon instructions from environment estimation means. The DHCP client processing means includes first DHCP information acquisition means that sends a DHCP Discover message to a DHCP server, and acquires an IP address and DHCP option information included in a DHCP Offer message from the DHCP server. When the information processing apparatus is in a fixed IP mode, the DHCP client processing means does not use the IP address acquired by the first DHCP information acquisition means.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an information processing device, a control method, and a program. [Background technology]

[0002] Information processing devices connected to a network are exposed to security threats. Therefore, various security-related settings must be configured appropriately. For example, multifunction peripherals (MFPs) that copy, print, and scan images can be used in a variety of environments, such as large offices, small offices, public spaces, and telecommuting environments. For this reason, security settings are available to address a variety of threat levels. However, there are many such security settings, and some of them can be difficult for users without specialized security knowledge to configure.

[0003] To address this issue, some multifunction devices have a function that allows users to configure multiple security settings at once by selecting conditions. The conditions to be selected include, for example, the type of environment in which the device is used and the security strength level. Furthermore, in recent years, technologies have been devised that enable information processing devices to estimate the environment in which they are placed and assist the user. By using these functions and technologies, even users without specialized security knowledge can configure appropriate security settings.

[0004] Generally, information processing devices use DHCP to learn about their environment. DHCP is an abbreviation for Dynamic Host Configuration Protocol. By communicating with a DHCP server, information processing devices can automatically obtain and connect to an IP address and network connection information, as well as learn various DHCP option information. IP is an abbreviation for Internet Protocol.

[0005] Incidentally, some information processing devices have server functions such as an HTTP server. HTTP is an abbreviation for Hypertext Transfer Protocol. In order for such information processing devices to function as a server device and provide server functions to external devices, it is desirable for the information processing device to be operated in a fixed IP mode in which the IP address does not change. This is because if the IP address is not fixed, other terminals will not be able to access the device by specifying the IP address, and settings will need to be changed each time.

[0006] Patent Document 1 discloses a terminal device that obtains an IP address using a DHCP server, and after obtaining the IP address, turns off the DHCP client function, allowing the obtained IP address to be used as a fixed IP address. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-005820 Summary of the Invention [Problem to be solved by the invention]

[0008] However, when an information processing device is operated with a fixed IP address and a function using DHCP is to be used, if the DHCP client function is turned off as in Patent Document 1, the function using DHCP becomes unavailable for that period.

[0009] The present invention has been made in view of the above points, and its object is to provide an information processing device that can use functions using DHCP at any timing in a device operated with a fixed IP address. [Means for solving the problem]

[0010] An information processing apparatus according to one embodiment of the present invention is an information processing apparatus connectable to a network, and includes: IP address mode switching means for switching between a fixed IP mode in which a predetermined fixed address is used as an IP address, and an automatic IP mode in which an address acquired from a DHCP server is used; IP address mode determination means for determining whether the mode is the fixed IP mode or the automatic IP mode; environment estimation means for estimating a usage environment of the information processing apparatus from DHCP option information; DHCP client processing means for executing a DHCP client function in response to an instruction from the environment estimation means; and DHCP information storage means for storing an IP address and DHCP option information, wherein the DHCP client processing means includes first DHCP information acquisition means for transmitting a DHCP Discover message to the DHCP server and acquiring the IP address and DHCP option information included in a DHCP Offer message from the DHCP server; and second DHCP information acquisition means for transmitting a DHCP Request message to the DHCP server and acquiring the DHCP Offer message from the DHCP server. and a second DHCP information acquisition means for acquiring the IP address and DHCP option information included in the Ack message, wherein the DHCP client processing means does not use the IP address acquired by the first DHCP information acquisition means when the information processing device is in the fixed IP mode. [Effects of the Invention]

[0011] According to the present invention, even in a device that is operated with a fixed IP address, functions that utilize DHCP can be used at any time. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a perspective view showing an example of the external configuration of an MFP according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a block diagram showing an example of the configuration of an MFP 300. [Figure 3] FIG. 2 is a diagram illustrating an example of the configuration of an operation display unit of the MFP 300. [Figure 4]FIG. 10 is a diagram illustrating an example of a LAN setting screen on the operation display unit of the MFP 300. [Figure 5] FIG. 10 is a diagram illustrating an example of a security setting screen on the operation display unit of the MFP 300. [Figure 6] 1 is a diagram illustrating an example of a system configuration according to a first embodiment of the present invention. [Figure 7] FIG. 10 is a diagram illustrating an example of a DHCP packet format. [Figure 8] FIG. 10 is a diagram illustrating an example of a sequence of the MFP 300. [Figure 9] FIG. 10 is a diagram illustrating an example of a sequence of the MFP 300. [Figure 10] 10 is a flowchart of the DHCP client processing unit 102. [Figure 11] 10 is a flowchart illustrating an example of an environment estimation unit 107. [Figure 12] 10 is a conceptual diagram showing an example of estimation processing by an environment estimation unit 107. FIG. [Figure 13] 10 is a flowchart illustrating an example of a DHCP client processing unit 102 according to the second embodiment of the present invention. [Figure 14] 10 is a flowchart illustrating an example of an environment estimation unit 107 according to the second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the claimed invention. Although multiple features are described in the embodiments, not all of these multiple features are necessarily essential to the invention, and multiple features may be combined arbitrarily. Furthermore, in the accompanying drawings, the same reference numerals are used to designate the same or similar components, and redundant explanations will be omitted.

[0014] [Embodiment 1] The information processing apparatus according to the first embodiment of the present invention is an MFP. MFP is an abbreviation for Multi Functional Peripheral. The MFP according to the first embodiment has a security-related setting function that allows a user to select an environment type of the apparatus from an operation panel and set multiple security settings at once. The MFP according to the first embodiment also has a function that automatically estimates the environment in which the apparatus is placed as a user assistance function for selecting the environment type.

[0015] [MFP external configuration] 1 is a perspective view showing an example of the external configuration of an MFP according to a first embodiment of the present invention. The MFP 300 includes an operation display unit 302, a print paper insertion slot 203, a print paper ejection slot 204, a document table 205, and a document table pressure plate 206. The operation display unit 302 is, for example, an operation panel. The housing of the MFP 300 is provided with a power button 301, which is a hard key used to turn the power on and off.

[0016] The operation display unit 302 includes a display and buttons used when operating the MFP 300. For example, the operation display unit 302 includes a plurality of keys such as character input keys, cursor keys, a confirmation key, and a cancel key, and a light source such as an LED or an LCD. LED is an abbreviation for Light Emitting Diode. LCD is an abbreviation for Liquid Crystal Display. The operation display unit 302 is configured to be able to accept operation inputs from the user when activating individual functions of the MFP 300, changing various settings, etc. Typically, a touch panel display can be used as the operation display unit 302, as will be described later with reference to FIG. 3.

[0017] The print paper insertion slot 203 is an insertion slot for setting paper of any size. Paper set in the print paper insertion slot 203 is transported one sheet at a time to the printing unit and printed, and the printed paper is discharged from the print paper discharge slot 204.

[0018] Platen 205 is a transparent glass platen on which an original is placed and used when reading an image using the scan function. Platen pressure plate 206 is a cover that presses the original against platen 205 to prevent the original from lifting off when reading an image using the scan function. Platen pressure plate 206 also blocks light from entering the inside of MFP300 main body from the outside.

[0019] The MFP 300 also has a communication function using a WLAN or a wired LAN. LAN is an abbreviation for Local Area Network. WLAN is an abbreviation for Wireless LAN. In this embodiment, the MFP 300 is provided with a wireless communication unit 307 including an antenna for realizing wireless communication, and a wired communication unit 321 for a wired LAN. The MFP 300 is also provided with a USB communication unit 308 that can realize communication with an external information processing device or the like via a USB (registered trademark) connection. USB is an abbreviation for Universal Serial Bus. The MFP 300 also has a power supply unit 309 that receives power from an external source.

[0020] [MFP configuration] 2 is a block diagram showing an example of the configuration of MFP 300. MFP 300 further includes a main board 310 that controls the entire device, and an external storage unit 322. Main board 310 includes a CPU 311, an internal bus 312, a program memory 313, a data memory 314, a print unit 316, a scan unit 317, a communication control unit 318, an operation control unit 319, a USB communication control unit 320, and a security management unit 323. CPU is an abbreviation for Central Processing Unit.

[0021] Note that the processes described below as processes executed by MFP 300 are actually realized by CPU 311 executing programs stored in program memory 313, data memory 314, and the like.

[0022] The CPU 311, the program memory 313, and the data memory 314 are respectively a microprocessor, a ROM, and a RAM. ROM is an abbreviation for Read Only Memory. RAM is an abbreviation for Random Access Memory.

[0023] In this embodiment, the CPU 311, program memory 313, and data memory 314 are connected to one another via a bus cable that forms an internal bus 312. The CPU 311 performs arithmetic processing to realize the individual functions described in this embodiment, based on the control program stored in the program memory 313 and the contents of the data memory 314.

[0024] For example, CPU 311 can control scan unit 317 to read an original and store the read image (image data) in image memory 315 within data memory 314. CPU 311 can control print unit 316 to print an image stored in image memory 315 onto a recording medium. CPU 311 can control USB communication unit 308 via USB communication control unit 320 to perform USB communication with an external information processing device via a USB connection. CPU 311 can control operation control unit 319 to receive information indicated by operation input from power button 301 or operation display unit 302. CPU 311 can also control operation control unit 319 to display the status of MFP 300 and a function selection menu on operation display unit 302.

[0025] The wireless communication unit 307 is configured to be able to provide a WLAN communication function. The wireless communication unit 307 transmits packets converted from data to other devices in a manner conforming to a predetermined standard, and also restores packets from other devices to the original data and outputs the data to the CPU 311. The wireless communication unit 307 is configured to be able to perform data (packet) communication in a WLAN system conforming to the IEEE802.11 standard series (IEEE802.11a / b / g / n / ac / ax, etc.), but may also conform to other standards.

[0026] The wired communication unit 321 is configured to be able to realize wired communication. For example, the wired communication unit 321 can realize data (packet) communication in a wired LAN (Ethernet (registered trademark)) system conforming to the IEEE802.3 series. Furthermore, wired communication using the wired communication unit 321 allows communication in a wired mode. Here, the wired communication unit 321 is connected to the main board 310 via a bus cable that forms the internal bus 312.

[0027] The external storage unit 322 is configured to permanently store information about the device, and is realized by, for example, a hard disk drive.

[0028] The security management unit 323 manages the function of setting multiple security settings at once by having the user select the usage environment of the main unit, and the function of estimating the usage environment in which the user is placed and presenting candidates to the user as an auxiliary function for selecting the usage environment of the user.

[0029] [MFP operation display section] 3A to 3C are diagrams schematically showing examples of the configuration of the operation display unit 302 of the MFP 300. FIG.

[0030] 3A shows an example of a display when MFP 300 employs touch panel display 401 as operation display unit 302. A user can start MFP 300 by touching power button 301. When MFP 300 starts up, a home screen (typically the top level of the menu) is displayed on touch panel display 401 as a screen on which the user can input operations.

[0031] The home screen includes a copy area 405, a scan area 406, and a print area 407. The copy area 405 accepts an instruction to execute a copy process. The scan area 406 accepts an instruction to execute a scan process. The print area 407 accepts an instruction to execute a print process.

[0032] The home screen may further include a status display area 402, a connection setting mode area 403, and a settings area 404. The status display area 402 indicates the settings and connection status of the MFP 300, such as infrastructure connection or direct connection. The connection setting mode area 403 allows the user to start operation in the connection setting mode at any time. The settings area 404 also allows the user to change various settings.

[0033] FIG. 3B shows an example in which the MFP 300 employs a relatively small LCD display 408 and various hard keys (409 to 416) as the operation display unit 302. In FIG.

[0034] When the MFP 300 starts up, a home screen is displayed on the LCD display 408. For example, menus such as "LAN settings" 431 and "main unit settings" 432 are displayed on the LCD display 408. The user can operate the position of the cursor on the menu displayed on the LCD display 408 by pressing cursor movement buttons 411 and 412. The user presses an OK button 414 to execute an operation, and a back button 413 to return to the previous menu screen.

[0035] Furthermore, the user can press QR button 409 to display a QR code (registered trademark) containing information necessary for direct connection with MFP 300. The code displayed here is not limited to a QR code, and may be any two-dimensional code. By reading this QR code with a camera unit or the like of an external information processing device, the external information processing device and MFP 300 are directly connected, enabling wireless communication between them.

[0036] The user can also start connection setting mode by pressing connection setting mode button 410, and can connect MFP 300 to an access point by sending connection information to MFP 300 using an external information processing device. If stop button 415 is pressed while MFP 300 is executing various processes, the various processes are canceled. The user can also scan an original document on MFP 300 and print it by pressing copy start button 416.

[0037] As shown in Fig. 3(C), the layout of Fig. 3(B) may be changed as appropriate, for example, the cursor may be operated in the left and right direction. Note that each of the components 408 to 416 described above may be simply referred to as a screen, and for example, in the following description, the LCD display 408 may also be referred to as the screen 408.

[0038] [IP address input screen flow] 4A to 4G are screen flow diagrams when "LAN settings" 431 is selected from the setting menu of screen 408 in FIG. 3B on operation display unit 302 of MFP 300. FIG.

[0039] Fig. 4(A) is a screen that is displayed when the user selects "LAN settings" 431 on screen 408, and is a screen that allows changes to LAN settings to be made. The screen of Fig. 4(A) shows "Wireless LAN" 501, "Wired LAN" 502, "P2P mode" 503, and "Advanced settings" 504 as options that the user can select. The P2P mode is Wireless Direct.

[0040] Fig. 4(B) is a screen that is displayed when the user selects "Advanced Settings" 504 on the screen of Fig. 4(A), and is a screen that allows changes to be made to the LAN advanced settings. The screen of Fig. 4(B) shows "TCP / IP Settings" 505 and "802.1X / EAP Settings" 506 as options that the user can select.

[0041] Fig. 4(C) is a screen that is displayed when the user selects "TCP / IP Settings" 505 on the screen of Fig. 4(B), and is a screen that allows changes to be made to the TCP / IP detailed settings. The screen of Fig. 4(C) shows "IPv4 Settings" 507 and "IPv6 Settings" 508 as options that the user can select.

[0042] Fig. 4(D) is a screen that is displayed when the user selects "IPv4 Settings" 507 on the screen of Fig. 4(C), and is a screen that allows changes to the IPv4 settings. The screen of Fig. 4(D) shows "IP Address" 509, "DNS Server" 510, and "Proxy Server" 511 as options that the user can select.

[0043] Fig. 4(E) is a screen that is displayed when the user selects "IP address" 509 on the screen of Fig. 4(D), and is a screen that allows the user to change the IP address setting. The screen of Fig. 4(E) shows "automatic setting" 512 and "manual setting" 513 as selection items that the user can select. When the user selects "automatic setting" 512 on the screen of Fig. 4(E), the MFP 300 enters the automatic IP mode. On the other hand, when the user selects "manual setting" 513 on the screen of Fig. 4(E), the MFP 300 enters the static IP mode, and the IP address entered in Fig. 4(G), which will be described later, is used.

[0044] Fig. 4(F) is a screen that is displayed when the user selects "Automatic Setting" 512 on the screen of Fig. 4(E), and indicates that the IP address automatic setting process is in progress. The screen of Fig. 4(F) displays an indicator 514 that indicates that the internal processing of MFP 300 has not stopped. The IP address is automatically set by MFP 300, and when the process is completed, the screen returns to the screen of Fig. 4(A).

[0045] Fig. 4(G) is a screen that is displayed when the user selects "Manual Setting" 513 on the screen of Fig. 4(E), and is a screen that allows manual input of an IP address. The screen of Fig. 4(G) displays an IP address display area 515 that shows the 12-digit IP address to be input by the user, an indicator 516 that shows the digit currently being input, and a guide display 517 that indicates that the user should press the stop button 415 when input is complete.

[0046] [Security settings screen flow] 5A to 5G are screen flow diagrams when "Main Unit Settings" 432 is selected from the settings menu of screen 408 in FIG. 3B on operation display unit 302 of MFP 300. FIG.

[0047] Fig. 5(A) is a screen that is displayed when the user selects "Device Settings" 432 on screen 408, and allows the user to change the device settings. The screen of Fig. 5(A) shows "Print Settings" 601, "Security Settings" 602, "Language Settings" 603, and "Other Settings" 604 as options that the user can select.

[0048] Fig. 5(B) is a screen that is displayed when the user selects "Security Settings" 602 on the screen of Fig. 5(A), and is a screen that allows the user to change the security settings. The screen of Fig. 5(B) shows "Recommended Security Settings" 605, "Lockout Settings" 606, and "Administrator Password Settings" 607 as options that the user can select.

[0049] Fig. 5(C) is a screen that is displayed when the user selects "Recommended Security Settings" 605 on the screen of Fig. 5(B), and is a screen that allows changes to security settings to be made. The screen of Fig. 5(C) shows the user-selectable options 608 for the usage environment, including "Highly Confidential Information Management," "Public Space," "Home," and "Company Intranet," as well as an "Automatic Environment Determination" button 609.

[0050] Fig. 5(D) is a confirmation screen displayed before security settings are executed when the user selects "Company Intranet" from the usage environment options 608 on the screen of Fig. 5(C). The screen of Fig. 5(D) displays an option area 610 showing the usage environment selected by the user, a "Yes" button 611 for permitting security settings to be executed, and a "No" button 612 for canceling security settings execution.

[0051] Fig. 5(E) is a screen that is displayed when the user selects "Yes" button 611 on the screen of Fig. 5(D), and indicates that security settings are being made. The screen of Fig. 5(E) displays indicator 613, which indicates that internal processing of MFP 300 has not stopped. At this time, multiple security setting items are set collectively within MFP 300 according to the selected usage environment, and when setting of all items is completed, MFP 300 automatically restarts.

[0052] Fig. 5(F) is a screen displayed when the "Automatic Environment Determination" button 609 is selected by the user on the screen of Fig. 5(C), and is a confirmation screen before the automatic environment determination is executed. The screen of Fig. 5(F) displays a "Yes" button 614 for permitting the execution of the automatic environment determination, and a "No" button 615 for canceling the execution of the automatic environment determination.

[0053] Fig. 5(G) is an automatic environment determination result screen that is displayed when the user selects the "Yes" button 614 on the screen of Fig. 5(F) and the automatic environment determination process is completed. The screen of Fig. 5(G) displays recommended environment options 616 as a result of the automatic environment determination, and a "Back" button 617 for returning to the screen of Fig. 5(C).

[0054] [System Configuration] 6 shows an example of a system configuration of an information processing apparatus and external devices that provide a security setting function according to embodiment 1. In this embodiment, the MFP 300 is connectable to a network 109. The network 109 is, for example, a LAN. A DHCP server 110 is connected to the network 109.

[0055] When an IP address assignment request is received from an MFP 300 having a DHCP client function connected to network 109, DHCP server 110 responds to the request and assigns an IP address to MFP 300. This allows MFP 300 to easily set an IP address.

[0056] The communication control unit 318 includes a NW connection unit 101, a DHCP client processing unit 102, and a communication unit 103. NW is an abbreviation for network. The NW connection unit 101 and the DHCP client processing unit 102 are connected to a network 109 via the communication unit 103.

[0057] When the MFP 300 is started up or when the user changes the LAN setting information using the operation / display unit 302, the NW connection unit 101 connects the MFP 300 to the network 109 using the connection information stored in the external storage unit 322. If the IP address is in automatic acquisition mode, the NW connection unit 101 instructs the DHCP client processing unit 102 to acquire connection information from the DHCP server 110 before connection.

[0058] The DHCP client processing unit 102 acquires connection information from the DHCP server 110 and stores the connection information in the external storage unit 322. The external storage unit 322 stores information related to the network, such as an IP address and a subnet mask. This information includes information acquired from the DHCP server 110 as well as information written by the operation control unit 319.

[0059] The security management unit 323 includes a security setting unit 106 and an environment estimation unit 107. The security setting unit 106 collectively sets multiple security setting items according to the usage environment selected by the user. Each setting value is stored in the external storage unit 322. The environment estimation unit 107, as an auxiliary function for the user's usage environment selection, estimates the usage environment in which the MFP 300 itself is placed and presents candidate usage environments to the user. The environment estimation unit 107 uses DHCP option information from the DHCP client processing unit 102 as information for determining the usage environment.

[0060] The external storage unit 322 stores DHCP option information acquired by the communication control unit 318 and security management unit 323, and setting values of operation menus acquired by the operation control unit 319 from the user via the operation display unit 302.

[0061] [DHCP packet] Figure 7(A) shows the DHCP packet format. A detailed explanation of each field is omitted here, but the packet format of a DHCP message that includes DHCP option information is defined in RFC2132. For example, the op field is the Message Operation Code and consists of 1 byte. op=1 indicates that the message is from the DHCP client. op=2 indicates that the message is from the DHCP server. The options field is optional information and is variable in length.

[0062] Figure 7(B) shows the packet format of DHCP Discover option information as an example of a message sent by a DHCP client. The beginning of the option field always contains "0x63, 0x82, 0x53, 0x63" called Magic Cookie, which indicates that it is a DHCP protocol. The option field always contains a number starting with 0x35 following the Magic Cookie. Here, 0x35 in hexadecimal is 53 in decimal, which is information called Option 53 that indicates the message type, such as Discover / Offer / Request / ACK. The 0x350101 shown in the figure indicates Discover.

[0063] The options field then contains numbers starting with 0x37. Here, 0x37 in hexadecimal is 55 in decimal, which is information indicating a "parameter request list" called Option 55. This is information requested from the client to the server. The 0x370401030f061 in the figure indicates that information on the subnet mask, router, domain name, and DNS server is requested. The 0xff at the end of the options field is a termination mark indicating the end of this packet.

[0064] Figure 7(C) shows the packet format of the DHCP Offer option information as an example of a message sent by a DHCP server. This packet is generated by the DHCP server that received the DHCP Discover shown in Figure 7(B).

[0065] The magic cookie at the beginning of Figure 7(C) is a required field, just like Figure 7(B). The following Option 53 information is also a required field, and in this case indicates that this is a DHCP Offer message. It is followed by a number starting with 0x01. This is a response to the parameter request list in Figure 7(B). In this example, only the subnet mask information is returned in response to multiple parameter requests from the client side. The 0xff at the end is a termination mark indicating the end of this packet.

[0066] Note that the parameter request list in a DHCP Discover or Request indicates the optional information the client wants from the server, and the server does not need to reply to all of it. The server only needs to reply with what it can answer in the relevant phase, and it is okay for there to be optional information that is not answered in the DHCP Offer but is answered in the Ack.

[0067] [DHCP sequence for network connection] 8 is a sequence diagram showing a DHCP sequence for automatically obtaining an IP address by MFP 300. This sequence is executed when MFP 300 is in automatic IP address acquisition mode upon startup or when MFP 300 is switched from static IP mode to automatic IP mode.

[0068] In step S701, the NW connection unit 101 requests the DHCP client processing unit 102 to transmit a DHCP Discover, which is an IP address search request. At this time, the IP address of the MFP 300 is in an undetermined state.

[0069] In step S702, the DHCP client processing unit 102 transmits a DHCP Discover to the DHCP server 110.

[0070] In step S703, the DHCP server 110 returns a DHCP Offer message to the DHCP client processing unit 102. At this time, the DHCP server 110 stores the IP address and option information to be presented to the DHCP client processing unit 102 in a message packet and returns the message. Note that there is not necessarily only one DHCP server in the network 109, and DHCP Offer messages may be returned from multiple DHCP servers. In this case, the DHCP client processing unit 102 performs subsequent processing for the DHCP server that returned a response first.

[0071] In step S704, the DHCP client processing unit 102 stores the IP address and option information returned from the DHCP client processing unit 102 in the external storage unit 322.

[0072] In step S705, the DHCP client processing unit 102 notifies the NW connection unit 101 that the processing requested by the NW connection unit 101 has been completed.

[0073] In step S706, the NW connection unit 101 requests the DHCP client processing unit 102 to transmit a DHCP Request, which is an IP address approval request.

[0074] In step S707, the DHCP client processing unit 102 transmits a DHCP Request to the DHCP server 110.

[0075] In step S708, the DHCP server 110 returns a DHCP Ack message to the DHCP client processing unit 102. At this time, the DHCP server 110 stores the IP address to be presented to the DHCP client processing unit 102 in a message packet and returns the message.

[0076] In step S709, the DHCP client processing unit 102 stores the IP address and option information returned from the DHCP client processing unit 102 in the external storage unit 322.

[0077] In step S710, the DHCP client processing unit 102 notifies the NW connection unit 101 that the processing requested by the NW connection unit 101 has been completed.

[0078] In step S711, the NW connection unit 101 reads from the external storage unit 322 the IP address and option information that the DHCP client processing unit 102 has stored in the external storage unit 322.

[0079] In step S712, the NW connection unit 101 uses the IP address and option information read from the external storage unit 322 to establish a connection to the network 109.

[0080] [DHCP processing sequence for obtaining environmental information] 9 is a sequence diagram showing processing between the environment estimation unit 107, the DHCP client processing unit 102, the DHCP server 110, and the external storage unit 322. It is assumed that the MFP 300 is operating in fixed IP mode. The DHCP client processing unit 102 and the DHCP server 110 are connected via a network. Upon receiving an instruction from the security setting unit 106, the environment estimation unit 107 starts processing from step S901.

[0081] In step S901, the environment estimation unit 107 requests the DHCP client processing unit 102 to transmit a DHCP Discover, which is an IP address search request. At this time, the environment estimation unit 107 instructs the DHCP server 110 to set information required for environment determination in the parameter request list of the message packet as DHCP option information to be requested.

[0082] In step S902, the DHCP client processing unit 102 transmits a DHCP Discover to the DHCP server 110.

[0083] In step S903, the DHCP server 110 returns a DHCP Offer message to the DHCP client processing unit 102. At this time, the DHCP server 110 stores in a message packet the IP address to be presented to the DHCP client processing unit 102 and any other items of the requested optional information that can be returned, and returns the message packet.

[0084] In step S904, the DHCP client processing unit 102 stores only the option information returned from the DHCP server 110 in the external storage unit 322. The reason for this is that the IP address must not be rewritten because the MFP 300 is operating in the fixed IP mode.

[0085] In step S905, the DHCP client processing unit 102 notifies the environment estimation unit 107 that the processing requested by the environment estimation unit 107 has been completed.

[0086] In step S906, the environment estimation unit 107 reads out from the external storage unit 322 the option information that the DHCP client processing unit 102 has stored in the external storage unit 322.

[0087] In step S907, the environment estimation unit 107 performs environment estimation using the option information read from the external storage unit 322. If environment estimation is possible, the processes from step S908 onwards are not performed.

[0088] In step S908, the environment estimation unit 107 requests the DHCP client processing unit 102 to transmit a DHCP Request, which is an IP address approval request. At this time, the environment estimation unit 107 instructs the DHCP server 110 to set information required for environment determination in the parameter request list of the message packet as DHCP option information to be requested.

[0089] In step S909, the DHCP client processing unit 102 transmits a DHCP Request to the DHCP server 110.

[0090] In step S910, the DHCP server 110 returns a DHCP Ack message to the DHCP client processing unit 102. At this time, the DHCP server 110 stores in a message packet the IP address approved by the DHCP client processing unit 102 and any other items of the requested optional information that can be returned, and returns the message packet.

[0091] In step S911, the DHCP client processing section 102 stores only the option information returned from the DHCP server 110 in the external storage unit 322. The reason for this is the same as in step S904.

[0092] In step S912, the DHCP client processing unit 102 notifies the environment estimation unit 107 that the processing requested by the environment estimation unit 107 has been completed.

[0093] In step S913, the environment estimation unit 107 requests the DHCP client processing unit 102 to send a DHCP Release message, which is an IP address release request. This is because the IP address presented and approved by the DHCP server 110 in the processes of steps S909 and S910 remains leased to the MFP 300. The MFP 300 is in fixed IP mode and will not use this IP address, so it returns it by DHCP Release.

[0094] In step S914, the DHCP client processing unit 102 transmits a DHCP Request to the DHCP server 110. This allows the DHCP server 110 to assign this IP address to another terminal or the like.

[0095] [DHCP client processing flow] 10 shows a processing flow of the DHCP client processing unit 102. Fig. 10(A) shows a processing flow that starts when the DHCP client processing unit 102 receives a DHCP Discover request from the environment estimation unit 107 in step S901 of Fig. 9.

[0096] In step S1001, the DHCP client processing unit 102 sets option information necessary for environment determination in the DHCP Discover frame. The option information necessary for environment determination is specified by the environment estimation unit 107.

[0097] In step S 1002 , the DHCP client processing unit 102 transmits a DHCP Discover message to the DHCP server 110 .

[0098] In step S 1003 , the DHCP client processing unit 102 receives a DHCP Offer message from the DHCP server 110 .

[0099] In step S1004, the DHCP client processing unit 102 determines whether the IP address of the MFP 300 is in fixed IP mode or automatic IP mode. If manual setting 513 is selected on the screen of FIG. 4(E), the DHCP client processing unit 102 determines that the IP address is in fixed IP mode. If the DHCP client processing unit 102 determines that the IP address is in fixed IP mode, the process of step S1006 is executed. If the DHCP client processing unit 102 determines that the IP address is not in fixed IP mode, the process of step S1005 is executed.

[0100] In step S1005, the DHCP client processing unit 102 executes processing for when the MFP 300 is not in the fixed IP mode. In this case, the DHCP client processing unit 102 stores the IP address and option information of the DHCP Offer message in the external storage unit 322 in step S1005.

[0101] In step S1006, the DHCP client processing section 102 executes processing for when the MFP 300 is in the fixed IP mode. In this case, in step S1006, the DHCP client processing section 102 stores only the option information of the DHCP Offer message in the external storage unit 322.

[0102] FIG. 10B shows a processing flow that is started when the DHCP client processing unit 102 receives a DHCP Request from the environment estimation unit 107 in step S906 of FIG.

[0103] In step S1011, the DHCP client processing unit 102 sets option information necessary for environment determination in the DHCP Request frame. The option information necessary for environment determination is specified by the environment estimation unit 107.

[0104] In step S 1012 , the DHCP client processing unit 102 transmits a DHCP Request message to the DHCP server 110 .

[0105] In step S 1013 , the DHCP client processing unit 102 receives a DHCP Ack message from the DHCP server 110 .

[0106] In step S1014, the DHCP client processing unit 102 determines whether the IP address of the MFP 300 is in the fixed IP mode or the automatic IP mode. If manual setting 513 is selected on the screen of FIG. 4(E), the DHCP client processing unit 102 determines that the mode is the fixed IP mode. If the DHCP client processing unit 102 determines that the mode is the fixed IP mode, the process of step S1016 is executed. If the DHCP client processing unit 102 determines that the mode is not the fixed IP mode, the process of step S1015 is executed.

[0107] In step S1015, the DHCP client processing unit 102 executes processing for when the MFP 300 is not in the fixed IP mode. In this case, in step S1015, the DHCP client processing unit 102 stores the IP address and option information of the DHCP Offer message in the external storage unit 322.

[0108] In step S1016, the DHCP client processing unit 102 executes processing for when the MFP 300 is in the fixed IP mode. In this case, in step S1015, the DHCP client processing unit 102 stores only the option information of the DHCP Offer message in the external storage unit 322.

[0109] FIG. 10C shows a processing flow that is started when the DHCP client processing unit 102 receives a DHCP release request from the environment estimation unit 107 in step S913 of FIG.

[0110] In step S1021, the DHCP client processing unit 102 sets information required to release the IP address in the DHCP Release frame.

[0111] In step S 1022 , the DHCP client processing unit 102 transmits a DHCP Release message to the DHCP server 110 .

[0112] [Processing flow of the environment estimation unit] Fig. 11 shows a processing flow of the environment estimation unit 107. The processing in Fig. 11 is started when the environment estimation unit 107 receives an environment estimation start request from the operation control unit 319. More specifically, the processing in Fig. 11 is started when the user selects the "Yes" button 614 on the screen of Fig. 5(F).

[0113] 11, steps S1101, S1105, and S1106 are connected to the processes performed by the DHCP client processing unit 102 corresponding to Figures 10(A), 10(B), and 10(C), respectively. When the processing of the DHCP client processing unit 102 is completed, the processes of steps S1101, S1105, and S1106 are also completed.

[0114] In step S1101, the environment estimation unit 107 requests the DHCP client processing unit 102 to send a DHCP Discover, which is an IP address search request. At this time, the environment estimation unit 107 instructs the DHCP server 110 to set information necessary for environment determination in the parameter request list of the message packet as DHCP option information to be requested. When the processing of step S1101 is completed, the option information from the DHCP server 110 is stored in the external storage unit 322.

[0115] In step S1102, the environment estimation unit 107 reads from the external storage unit 322 the DHCP option information acquired as a result of the DHCP Discover / Offer process.

[0116] In step S1103, the environment estimation unit 107 performs environment estimation using the DHCP option information read from the external storage unit 322.

[0117] In step S1104, the environment estimation unit 107 determines whether or not the environment has been estimated. If the environment estimation unit 107 determines that the environment has been estimated, the process proceeds to step S1109. If the environment estimation unit 107 determines that the environment has not been estimated, the process proceeds to step S1005.

[0118] In step S1105, the environment estimation unit 107 requests the DHCP client processing unit 102 to send a DHCP Request, which is a request for IP address approval. At this time, the environment estimation unit 107 instructs the DHCP server 110 to set the information set in step S1101 again in the parameter request list of the message packet as DHCP option information to be requested. When the processing of step S1105 is completed, the option information from the DHCP server 110 is stored in the external storage unit 322.

[0119] In step S1106, the environment estimation unit 107 requests the DHCP client processing unit 102 to transmit a DHCP Release, which is an IP address approval request.

[0120] In step S1107, the environment estimation unit 107 reads from the external storage unit 322 the DHCP option information that has been acquired as a result of the DHCP Request / Ack processing.

[0121] In step S1108, the environment estimation unit 107 performs environment estimation using the DHCP option information read from the external storage unit 322.

[0122] In step S1109, the environment estimation unit 107 notifies the operation control unit 319 of the environment estimation result.

[0123] [Environment estimation processing] Fig. 12 shows a conceptual diagram of the estimation process of the environment estimation unit 107. Fig. 12(A) is an example of a combination table for determining the environment type from the combination of values of DHCP option information. The environment estimation unit 107 holds this combination table and estimates the environment type by comparing the DHCP option information stored in the external storage unit 322 with the held combination table.

[0124] There are three types of environments to be estimated: public space, home, and company intranet. The DHCP option information required for environment estimation is the DNS domain name, DNS server address, and DHCP server identification information. Environment estimation is possible when the environment type can be uniquely identified from the DHCP option information.

[0125] Figures 12(B) and 12(C) are examples of DHCP option information sets. Figure 12(B) is an example where environment estimation is possible. In this example, there is no DNS domain name information (not set), the DNS server address is set to the local IP address 192.168.1.1, and the DHCP server identification information is set to the local IP address 192.168.1.2. In this case, by comparing the DHCP option information in Figure 12(B) with the table in Figure 12(A), the environment type can be estimated to be at home.

[0126] Figure 12(C) is an example where environment estimation is not possible. In this example, there is no DNS domain name information (not set), there is no DNS server address (neither a global nor a local IP address), and the DHCP server identification information is set to the local address value of 192.168.1.2. In this case, when the DHCP option information in Figure 12(C) is compared with the table in Figure 12(A), the environment type is likely to be a public space or at home, and cannot be identified. Therefore, in the example of Figure 12(C), environment estimation is not possible.

[0127] [Embodiment 2] The second embodiment is another embodiment that achieves the same effects as the first embodiment. In the second embodiment, only the differences from the first embodiment will be described. In the second embodiment, the environment estimation unit 107 stores the IP address before the environment estimation process, and restores the fixed IP address of the MFP 300 that was rewritten by the environment estimation process after the environment estimation.

[0128] [DHCP processing sequence for obtaining environmental information] 13 shows a processing flow of the DHCP client processing unit 102 according to the second embodiment of the present invention. The second embodiment differs from the first embodiment shown in FIG. 9 in that the information stored in the external storage unit 322 by the DHCP client processing unit 102 in steps S1304 and S1311 includes an IP address. Therefore, a detailed description of the processing of the second embodiment will be omitted. An advantage of the second embodiment is that the processing of the DHCP client processing unit 102 can be made common between the case of a processing request from the NW connection unit 101 and the case of a processing request from the environment estimation unit 107.

[0129] [Environment estimation processing] Fig. 14 shows a processing flow of the environment estimation unit 107 according to the second embodiment of the present invention. The second embodiment differs from Fig. 11 of the first embodiment in that steps S1401 and S1411 are added.

[0130] The processing in FIG. 14 is started when the environment estimation unit 107 receives an environment estimation start request from the operation control unit 319, as in the first embodiment.

[0131] In step S1401, the environment estimation unit 107 temporarily stores the IP address used by the MFP 300. The processes from step S1402 to step S1410 are the same as the processes from step S1101 to step S1108 in FIG.

[0132] In step S1402, the environment estimation unit 107 requests the DHCP client processing unit 102 to send a DHCP Discover, which is an IP address search request. At this time, the environment estimation unit 107 instructs the DHCP server 110 to set information necessary for environment determination in the parameter request list of the message packet as DHCP option information to be requested. When the processing of step S1402 is completed, the option information from the DHCP server 110 is stored in the external storage unit 322.

[0133] In step S1403, the environment estimation unit 107 reads from the external storage unit 322 the DHCP option information acquired as a result of the DHCP Discover / Offer process.

[0134] In step S 1404 , the environment estimation unit 107 performs environment estimation using the DHCP option information read from the external storage unit 322 .

[0135] In step S1405, the environment estimation unit 107 determines whether or not the environment has been estimated. If the environment estimation unit 107 determines that the environment has been estimated, the process proceeds to step S1410. If the environment estimation unit 107 determines that the environment has not been estimated, the process proceeds to step S1406.

[0136] In step S1406, the environment estimation unit 107 requests the DHCP client processing unit 102 to send a DHCP Request, which is a request for IP address approval. At this time, the environment estimation unit 107 instructs the DHCP server 110 to set again the information set in step S1101 in the parameter request list of the message packet as DHCP option information to be requested. When the processing of step S1406 is completed, the option information from the DHCP server is stored in the external storage unit 322.

[0137] In step S1407, the environment estimation unit 107 requests the DHCP client processing unit 102 to transmit a DHCP Release, which is an IP address approval request.

[0138] In step S1408, the environment estimation unit 107 reads from the external storage unit 322 the DHCP option information that has been acquired as a result of the DHCP Request / Ack processing.

[0139] In step S 1409 , the environment estimation unit 107 performs environment estimation using the DHCP option information read from the external storage unit 322 .

[0140] The process of step S1410 is different from that of embodiment 1. In step S1410, the environment estimation unit 107 writes the IP address stored in step S1401 back to the area for storing IP addresses in the external storage unit 322. This process restores the IP address that the DHCP client processing unit 102 wrote to the external storage unit 322 during the process of step S1402 or step S1406.

[0141] In step S1411, the environment estimation unit 107 notifies the operation control unit 319 of the environment estimation result.

[0142] 5(E) is displayed on the operation display unit 302 during the processing of the processing flow in Fig. 14. Therefore, the LAN settings are not changed by user operations during this time, and the IP address before being written back by the environment estimation unit 107 in step S1410 is not used by the NW connection unit 101.

[0143] For example, an information processing device may be operated with a fixed IP address in order to provide a server function to other devices. By configuring the information processing device as described above, even when the information processing device is operated with a fixed IP address, the information processing device can use functions that utilize DHCP at any time.

[0144] The names of the individual elements or functional units described in the above embodiments are expressed in this specification based on their main functions, but may also be expressed based on their sub-functions. Therefore, the present invention is not strictly limited to such expressions (the expressions can be replaced with similar expressions).

[0145] (Other embodiments) The present invention may be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in a computer of the system or device read and execute the program. For example, the present invention may be realized by a circuit (e.g., an ASIC) that realizes one or more functions.

[0146] The invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention.

[0147] The disclosure of this embodiment includes the following configuration, method, and program. (Configuration 1) An information processing device connectable to a network, an IP address mode switching means for switching between a fixed IP mode in which a predetermined fixed address is used as an IP address and an automatic IP mode in which an address obtained from a DHCP server is used; an IP address mode determining means for determining whether the mode is the fixed IP mode or the automatic IP mode; an environment estimation means for estimating a usage environment of the information processing device from DHCP option information; DHCP client processing means for executing a DHCP client function in response to an instruction from the environment estimation means; DHCP information storage means for storing IP addresses and DHCP option information; and The DHCP client processing means a first DHCP information acquisition means for transmitting a DHCP Discover message to the DHCP server and acquiring an IP address and DHCP option information included in a DHCP Offer message from the DHCP server; a second DHCP information acquisition means for transmitting a DHCP Request message to the DHCP server and acquiring an IP address and DHCP option information included in a DHCP Ack message from the DHCP server; Including, the DHCP client processing means does not use the IP address acquired by the first DHCP information acquisition means when the information processing device is in the fixed IP mode; 1. An information processing device comprising: (Configuration 2) When the information processing device is in the fixed IP mode, the DHCP client processing means does not store the IP address acquired by the first DHCP information acquisition means in the DHCP information storage means. 2. The information processing device according to configuration 1, (Configuration 3) When the environment estimation means is able to estimate the environment using the DHCP information acquired by the first DHCP information acquisition means, the environment estimation means does not acquire DHCP information using the second DHCP information acquisition means. 3. The information processing device according to configuration 1 or 2. (Configuration 4) An information processing device connectable to a network an IP address mode switching means for switching between a fixed IP mode in which a predetermined fixed address is used as an IP address and an automatic IP mode in which an address obtained from a DHCP server is used; an IP address mode determining means for determining whether the mode is the fixed IP mode or the automatic IP mode; an environment estimation means for estimating a usage environment of the information processing device from DHCP option information; DHCP client processing means for executing a DHCP client function in response to an instruction from the environment estimation means; DHCP information storage means for storing IP addresses and DHCP option information; and The DHCP client processing means a first DHCP information acquisition means for transmitting a DHCP Discover message to the DHCP server, acquiring an IP address and DHCP option information included in a DHCP Offer message from the DHCP server, and writing the IP address and DHCP option information into a DHCP information storage means; Sending a DHCP Request message to the DHCP server; a second DHCP information acquisition means for acquiring the IP address and DHCP option information included in the DHCP Ack message from the DHCP server and writing the IP address and DHCP option information into a DHCP information storage means; Including, the environment estimation means stores in advance an IP address of the information processing device, When the information processing device is in the fixed IP mode, the first DHCP information acquisition means or the second DHCP information acquisition means stores the IP address in the DHCP information storage means, and then writes the pre-stored IP address back to the DHCP information storage means. 1. An information processing device comprising: (Method 1) A method for controlling an information processing device connectable to a network, comprising: an IP address mode switching step of switching between a fixed IP mode in which a predetermined fixed address is used as an IP address and an automatic IP mode in which an address obtained from a DHCP server is used; an IP address mode determination step of determining whether the mode is the fixed IP mode or the automatic IP mode; an environment estimation step of estimating a usage environment of the information processing device from DHCP option information; a DHCP client processing step of executing a DHCP client function in response to an instruction from the environment estimation step; and The DHCP client processing step includes: a first DHCP information acquisition step of transmitting a DHCP Discover message to the DHCP server and acquiring an IP address and DHCP option information included in a DHCP Offer message from the DHCP server; a second DHCP information acquisition step of transmitting a DHCP Request message to the DHCP server and acquiring an IP address and DHCP option information included in a DHCP Ack message from the DHCP server; Including, the DHCP client processing step does not use the IP address acquired in the first DHCP information acquisition step when the information processing device is in the fixed IP mode; 2. A method for controlling an information processing apparatus comprising: (Program 1) A program executed on an information processing device connectable to a network, Computer, an IP address mode switching means for switching between a fixed IP mode in which a predetermined fixed address is used as an IP address and an automatic IP mode in which an address obtained from a DHCP server is used; an IP address mode determining means for determining whether the mode is the fixed IP mode or the automatic IP mode; an environment estimation means for estimating a usage environment of the information processing device from DHCP option information; DHCP client processing means for executing a DHCP client function in response to an instruction from the environment estimation means; and DHCP information storage means for storing IP addresses and DHCP option information; It functions as The DHCP client processing means a first DHCP information acquisition means for transmitting a DHCP Discover message to the DHCP server and acquiring an IP address and DHCP option information included in a DHCP Offer message from the DHCP server; a second DHCP information acquisition means for transmitting a DHCP Request message to the DHCP server and acquiring an IP address and DHCP option information included in a DHCP Ack message from the DHCP server; Including, the DHCP client processing means does not use the IP address acquired by the first DHCP information acquisition means when the information processing device is in the fixed IP mode; A program characterized by: [Explanation of symbols]

[0148] 300 MFP 318 Communication Control Unit 107 Environmental Estimation Department 102 DHCP client processing section

Claims

1. An information processing device connectable to a network, an IP address mode switching means for switching between a fixed IP mode in which a predetermined fixed address is used as an IP address and an automatic IP mode in which an address obtained from a DHCP server is used; an IP address mode determining means for determining whether the mode is the fixed IP mode or the automatic IP mode; an environment estimation means for estimating a usage environment of the information processing device from DHCP option information; a DHCP client processing means for executing a DHCP client function in response to an instruction from the environment estimation means; DHCP information storage means for storing IP addresses and DHCP option information; and The DHCP client processing means a first DHCP information acquisition means for transmitting a DHCP Discover message to the DHCP server and acquiring an IP address and DHCP option information included in a DHCP Offer message from the DHCP server; a second DHCP information acquisition means for transmitting a DHCP Request message to the DHCP server and acquiring an IP address and DHCP option information included in a DHCP Ack message from the DHCP server; Including, the DHCP client processing means does not use the IP address acquired by the first DHCP information acquisition means when the information processing device is in the fixed IP mode; 1. An information processing device comprising:

2. the DHCP client processing means does not store the IP address acquired by the first DHCP information acquisition means in the DHCP information storage means when the information processing device is in the fixed IP mode; 2. The information processing apparatus according to claim 1, wherein:

3. When the environment estimation means is capable of estimating the environment based on the DHCP information acquired by the first DHCP information acquisition means, the environment estimation means does not acquire the DHCP information by the second DHCP information acquisition means.

2. The information processing apparatus according to claim 1, wherein:

4. An information processing device connectable to a network an IP address mode switching means for switching between a fixed IP mode in which a predetermined fixed address is used as an IP address and an automatic IP mode in which an address obtained from a DHCP server is used; an IP address mode determining means for determining whether the mode is the fixed IP mode or the automatic IP mode; an environment estimation means for estimating a usage environment of the information processing device from DHCP option information; a DHCP client processing means for executing a DHCP client function in response to an instruction from the environment estimation means; DHCP information storage means for storing IP addresses and DHCP option information; and The DHCP client processing means a first DHCP information acquisition means for transmitting a DHCP Discover message to the DHCP server, acquiring an IP address and DHCP option information included in a DHCP Offer message from the DHCP server, and writing the IP address and DHCP option information into a DHCP information storage means; a second DHCP information acquiring means for transmitting a DHCP Request message to the DHCP server, acquiring an IP address and DHCP option information included in a DHCP Ack message from the DHCP server, and writing the IP address and DHCP option information into a DHCP information storing means; Including, the environment estimation means pre-stores an IP address of the information processing device, and when the information processing device is in the fixed IP mode, writes the pre-stored IP address back to the DHCP information storage means after the first DHCP information acquisition means or the second DHCP information acquisition means stores the IP address in the DHCP information storage means; 1. An information processing device comprising:

5. A method for controlling an information processing device connectable to a network, comprising: an IP address mode switching step of switching between a fixed IP mode in which a predetermined fixed address is used as an IP address and an automatic IP mode in which an address obtained from a DHCP server is used; an IP address mode determination step of determining whether the mode is the fixed IP mode or the automatic IP mode; an environment estimation step of estimating a usage environment of the information processing device from DHCP option information; a DHCP client processing step for executing a DHCP client function in response to an instruction from the environment estimation step; and The DHCP client processing step includes: a first DHCP information acquisition step of transmitting a DHCP Discover message to the DHCP server and acquiring an IP address and DHCP option information included in a DHCP Offer message from the DHCP server; a second DHCP information acquisition step of transmitting a DHCP Request message to the DHCP server and acquiring an IP address and DHCP option information included in a DHCP Ack message from the DHCP server; Including, the DHCP client processing step does not use the IP address acquired in the first DHCP information acquisition step when the information processing device is in the fixed IP mode; 2. A method for controlling an information processing apparatus comprising:

6. A program executed on an information processing device connectable to a network, Computer, an IP address mode switching means for switching between a fixed IP mode in which a predetermined fixed address is used as an IP address and an automatic IP mode in which an address obtained from a DHCP server is used; an IP address mode determining means for determining whether the mode is the fixed IP mode or the automatic IP mode; an environment estimation means for estimating a usage environment of the information processing device from DHCP option information; DHCP client processing means for executing a DHCP client function in response to an instruction from the environment estimation means; and DHCP information storage means for storing IP addresses and DHCP option information; It functions as The DHCP client processing means a first DHCP information acquisition means for transmitting a DHCP Discover message to the DHCP server and acquiring an IP address and DHCP option information included in a DHCP Offer message from the DHCP server; a second DHCP information acquisition means for transmitting a DHCP Request message to the DHCP server and acquiring an IP address and DHCP option information included in a DHCP Ack message from the DHCP server; Including, the DHCP client processing means does not use the IP address acquired by the first DHCP information acquisition means when the information processing device is in the fixed IP mode; A program characterized by:

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