JP2000316002A - Dynamic host configuration server and dynamic host configuration method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a dynamic host configuration server that effectively utilizes an IP address and a dynamic host configuration method that copes with diversified clients and copes with a change in setting contents. SOLUTION: A server 100 selects an IP address not assigned on request of an IP address assignment from a client, assigns this IP address to the client up to a prescribed assignment limit, forcibly recovers the IP address even when the assignment period is not invalidated in the case that the unassigned IP addresses are not left and when no reply is received from this client after transmitting an ICMP echo request message to the client to which the IP address has already been assigned and uses this IP address for the assignment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a server in which a server notifies a client of an IP address and values of various setting items, and a host configuration method thereof. The present invention relates to a dynamic host configuration method capable of responding to a dynamic host configuration server and various clients, and capable of responding to a change in setting contents.

[0002]

2. Description of the Related Art In order for a computer (hereinafter, also referred to as a terminal) having an IP (Internet Protocol) communication function to perform communication, an IP address of its own station is set, and an IP address of a default gateway or a name server is set. Various items such as the domain name must be set correctly. Conventionally, such a setting is manually performed by a person, and a network administrator manages the IP address so that the same IP address does not overlap with a plurality of terminals. However, due to the spread of mobile computers such as notebook personal computers and mobile terminals, connection and removal of terminals from networks have become frequent. Therefore, IP
The effort required to manage addresses is increasing.

[0003] As a method of automating the management work and reducing the work of the network administrator, DHCP (Dynamic Host) is used.
The Configuration Protocol (RFC2131) is becoming widespread. In this method, when a terminal having a DHCP client function (hereinafter, referred to as a client) requests the DHCP server to assign an IP address, the DHCP server sends a request to any other client from among a plurality of IP addresses registered in advance. Select an IP address that has not been assigned yet and assign it to the client. When the client notifies the DHCP server of the setting items (such as the IP address of the default gateway), the DHCP server notifies the client of a preset value.

[0004] In addition, the DHCP server sends an I
P addresses can be assigned with a time limit. The IP address whose assignment period has passed is collected by the DHCP server. Therefore, if the user connects the mobile computer to the network and uses the IP address for a short period of time and then removes the mobile computer, the IP address will be expired after the expiration of the assignment period.
Since the address is collected, the DHCP server uses this IP
The address can be assigned to another computer. Thereby, a finite IP address can be reused.

[0005] For example, Windows personal computer, Mac
Intosh personal computer, UNIX computer, DHCP
It has a client function. In addition, Windows
ws is a trademark of Microsoft OS, Macinto
sh is a trademark of Apple Computer (including OS), UN
IX is the name of the OS developed by Bell Labs.

[0006]

The DHCP client no longer needs the IP address before the expiration of the assignment, and sends a release message to the DHCP server when it abandons the IP address. The DHCP server that has received the release message can assign its IP address to another computer. Normally, when the user shuts down the client (system shutdown procedure performed before turning off the power), the client sends the release message to the DHCP server. However, the mobile computer is often physically disconnected from the network without being shut down, and in such a case, the release message is sent to the DH.
Cannot send to CP server. The conventional DHCP server does not assign the IP address to another computer until the IP address is returned from the client until the assignment deadline. Therefore, when a mobile computer is frequently connected and disconnected, the number of IP addresses that cannot be allocated to other clients increases because the allocation time limit has not passed even though the client has already been removed, and the IP address becomes insufficient. I will.

Further, necessary setting items differ depending on the model of the client and the OS. For example, in the case of a Windows personal computer, a NetBIOS name server or Net
BIOS node type, N in case of UNIX computer
IS (Network Information Service) server and X Wi
It is necessary to set the server related to the next system. However, the conventional DHCP server does not have a function of changing the notification content according to the type of the client or the OS.

A conventional DHCP server responds only when requested by a client, and does not spontaneously send a message when not requested. Therefore,
Even if the network administrator changes the settings of the DHCP server, the DHCP server does not notify the client of new setting values unless requested by the client. Normally, the client sends a request message to the DHCP server only at startup or after a certain percentage of the allocation period has elapsed, so it takes a very long time before the client setting items are updated. I will. For this reason, the client cannot cope with the new environment, and in particular, the default gateway and the name server I
When the P address is changed, the client cannot communicate normally unless a new setting value is immediately notified.

Accordingly, an object of the present invention is to solve the above-mentioned problems, to provide a dynamic host configuration server capable of effectively using an IP address, a dynamic host configuration server capable of responding to various clients, and capable of responding to a change in setting contents. The purpose of the present invention is to provide a translation method.

[0010]

To achieve the above object, a dynamic host configuration server according to claim 1 is registered in advance when a client on a network is requested to assign an IP address. An IP address that has not been assigned to any other client is selected from the plurality of IP addresses, and this IP address is assigned to the client until a predetermined assignment expiration date. I to the client assigning the address
When a CMP echo request message is transmitted and there is no response from this client, the IP address is forcibly collected from this client even if the assignment expiration date has not elapsed, and this IP address is used for assignment.

[0011] In the dynamic host configuration method according to the second aspect, a client requesting the server to allocate an IP address notifies the server of its model and OS to the server. From among a plurality of registered IP addresses, an IP address not yet assigned to any other client is selected and assigned to the client, and the model and the type of the client are selected from among a plurality of pre-registered setting items. O
The item related to S is selected and the value of the item is notified to the client.

[0012] In the dynamic host configuration method according to the third aspect, the server requested to assign an IP address from the client can send the server to any other client among the plurality of IP addresses registered in advance. A non-assigned IP address is selected and assigned to the client, the values of a plurality of setting items set in the own station are notified to the client, and the values of the setting items set in the server are changed by the network administrator. Is changed by the server, the server voluntarily notifies the client of the new value of the setting item, and the client always waits for the notification from the server, and when the client receives the notification of the new value of the setting item, , The setting item is updated to a new value.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the accompanying drawings.

As shown in FIG. 1, a dynamic host configuration server 100 according to the present invention
01, a volatile memory 102, a nonvolatile memory 103, an Ethernet MAC control LSI 104, and a port 105. The non-volatile memory 103 stores a program for implementing the present invention and configuration information (such as an IP address and various setting information). The program is executed by the CPU 101. At this time, assignment of an IP address, selection of a setting item, notification of a setting value, and the like are performed using the configuration information.

FIG. 2 shows a network configuration. 200 is a dynamic host configuration server, 201 and 20
2, 203, 204 and 206 are desktop personal computers,
205 is a notebook computer, and 207 is a hub for relaying communication between these network devices.

The program transmits an ICMP echo request message to a client to which an IP address has been assigned in addition to the processing of the conventional DHCP server, and transmits information as to whether or not an ICMP response message has been received from the client within a predetermined time. A process for storing in the volatile memory 102 is performed.

FIGS. 3 and 4 show the contents of the volatile memory 102. FIG. As shown in the figure, the volatile memory 102 is tabulated, and information managed by the program regarding the assignment of the IP address is stored in each column. 300, 40
0 is an IP address column registered in the dynamic host configuration server, 301 and 401 are IP address assignment status columns, 302 and 402 are assignment expiration columns, and 303 and 403 are responses of an IDMP echo request message. It is a column of presence or absence.

First, in FIG. 3, six IP addresses are registered, but no IP address has yet been assigned to the client. In the unassigned state,
Nothing is stored in the column 302 of the assignment term and the column 303 of the presence or absence of a response.

Next, in FIG. 4, all the IP addresses registered in FIG. 3 are assigned to the client. Then, the IP address 192.168.0.253
It is assumed that the client (notebook personal computer 205 in FIG. 2) to which has been assigned is omitted from the network by omitting the shutdown process. The above program sends an ICMP echo request message to each client, but since the notebook computer 205 has been removed from the network, there is no response only for the IP address. Therefore, no response is stored in the response presence / absence column 403.

Here, it is assumed that a new client is connected to the hub 207 in FIG. When the client requests the assignment of an IP address, the above program is executed as shown in FIG.
The processing is performed according to the flow of. First, the above program
Currently unassigned I among registered IP addresses
The volatile memory 102 is searched for a P address. If there is an unassigned IP address, the IP address is selected and notified to the client. When there is no unassigned IP address as shown in FIG.
Search for an IP address that has not received the ICMP echo response message. If there is no unanswered IP address, the process ends without doing anything. If there is an unanswered IP address, the IP address is selected and notified to the client. As shown in FIG.
For 2.168.0.253, the column 40 of the response presence / absence
No. 3 is stored in the IP address 19
Notify the client of 2.168.0.253.

Next, another embodiment of the present invention will be described.

First, the structure of a conventional DHCP message will be described with reference to FIG. The DHCP area includes a DHCP header 605 and a DHCP option 606. The area of the DHCP option 606 is variable length,
Basically, it is a list of an option code (1 byte), an option length (1 byte), and option data (the number of bytes indicated in the option length).

In the dynamic host configuration method of the present invention, the DHCP message transmitted by the client is, as shown in FIG.
In addition to the options used by the conventional DHCP client (hereinafter referred to as common options), model options and OS options are added. The model options and OS options are option codes 701 and 7
04, option lengths 702 and 705, and option data 703 and 706. The area of the model option data 703 stores hardware information of the client, and the area of the OS option data 706 stores OS information of the client.

In the dynamic host configuration method of the present invention, the nonvolatile memory 103 of the server is tabulated as shown in FIG. 8, and information is stored in each column. These pieces of information are set in advance by the network administrator, and are referred to by the program. 800 is a column for setting items, 8
01 is a set value column, and these information are stored in a conventional DHC
This information is also set in the P server. The server according to the present invention sets, in addition to these pieces of information, information 802 indicating which model or OS client needs each setting item. In the example of FIG. 8, the subnet mask, the default gateway, and the DSN server are items (common setting items) required for all clients.
IOS name server, NetBIOS node type is W
This is an item required for an Windows client, and the NIS domain name and the X Window font server are set as items required for a UNIX client.

When the server according to the present invention receives a DHCP message in which the model option and the OS option are added to the common option from the client, the server refers to the area of the model option and the OS option, and if the client is a Windows system, Refers to the non-volatile memory 103 and notifies the client of common setting items and Windows-related setting items. When the client is a UNIX system, the nonvolatile memory 10
3, the client is notified of the common setting items and the UNIX-related setting items.

Next, another embodiment of the present invention will be described.

In the dynamic host configuration method of the present invention, the client program is a conventional DH
In addition to the process of the CP client, a process of always waiting for a setting change message from the server is performed. On the other hand, the server program performs a process of transmitting a setting change message to the client when the information of the setting item is added, changed, or deleted by the network administrator, in addition to the processing of the conventional DHCP server. The setting change message that notifies addition, change, and deletion is configured by adding information to an option area of a conventional DHCP message.

FIG. 9 shows the DHCP option area of the setting change message. In the option area 900,
Code 901 of changed setting item, data length 902,
A list of data 903 is stored. For the deleted setting item, a list of the code 904 and the data length 905 is stored, and 0 is stored in the area of the data length 905.

Upon receiving the setting change message, the client reads the option area 900 of the setting change message and immediately adds / changes the setting of its own station. For the setting item whose data length is 0, the setting of the own station is deleted.

[0030]

The present invention exhibits the following excellent effects.

(1) According to the first aspect of the present invention, if a client has already left the network even if the assignment expiration date has not passed, the IP address assigned to that client is sent to another client. Can be assigned. Therefore, shortage of IP addresses can be prevented when the number of IP addresses is small or when computers are frequently moved.

(2) According to the second aspect of the present invention, the server can automatically select and notify the value of the setting item related to the client model and the OS. In a network in which various types of computers coexist, there is a great effect on reducing the labor of the network administrator.

(3) According to the third aspect of the invention, when the value of the setting item is changed by the network administrator, the server can immediately notify the client of the new setting value. Therefore, the client settings can be updated and the client can be adapted to the new environment without restarting the client. When the number of clients is large, there is a great effect on reducing the labor of the network administrator.

[Brief description of the drawings]

FIG. 1 is a hardware configuration diagram of a dynamic host configuration server according to an embodiment of the present invention.

2 is a network configuration diagram of a network using the dynamic host configuration server of FIG. 1;

FIG. 3 is a diagram of IP address assignment management information stored in a nonvolatile memory of FIG. 1;

FIG. 4 is a diagram of IP address assignment management information stored in a nonvolatile memory of FIG. 1;

5 is a flowchart of a process performed by the dynamic host configuration server in FIG. 1 in response to an IP address assignment request.

FIG. 6 is a configuration diagram of a DHCP message.

FIG. 7 is a configuration diagram of an optional area of a DHCP message used in the dynamic host configuration method of the present invention.

FIG. 8 is a diagram of setting information stored in a nonvolatile memory of FIG. 1;

FIG. 9 is a configuration diagram of an optional area of a DHCP message used in the dynamic host configuration method of the present invention.

[Explanation of symbols]

100, 200 Dynamic host configuration server 101 CPU 102 Volatile memory 103 Non-volatile memory 201, 202, 203, 204, 206 Desktop personal computer 205 Note personal computer

Claims (3)

[Claims] 1. A client on a network receives an IP
When an address assignment is requested, an IP address that has not been assigned to any other client is selected from a plurality of IP addresses registered in advance, and this IP address is selected.
When a P address is assigned to the client until a predetermined assignment expiration date and there are no unassigned IP addresses, and when an ICMP echo request message is transmitted to a client to which an IP address has already been assigned, and there is no response from this client, A dynamic host configuration server which forcibly collects an IP address from a client even if the assignment expiration date has not elapsed, and uses the IP address for assignment. 2. A client requesting a server to assign an IP address notifies the server of its own model and OS, and the server receiving the notification sends another server from among a plurality of IP addresses registered in advance. An IP address not yet assigned to any client is selected and assigned to the client, and an item related to the model and OS of the client is selected from a plurality of pre-registered setting items, and the value of the item is selected. A dynamic host configuration method. 3. A server which has been requested by a client to assign an IP address is assigned to a plurality of registered IP addresses.
From among the P addresses, an IP address not yet assigned to any other client is selected and assigned to the client, and the values of a plurality of setting items set in the own station are notified to the client. When the value of the set item is changed by the network administrator, the server voluntarily notifies the client of the new value of the set item, and the client always waits for the notification from the server, A dynamic host configuration method characterized by updating a setting item to a new value when a notification of a new value of the item is received.