KR101538737B1 - Method for IP allocation in DHCP - Google Patents

Abstract

The present invention relates to an IP allocation method using a dynamic host configuration protocol (DHCP) in a virtual local area network (VLAN) where the DHCP server and a terminal is connected through a gateway. An embodiment of the present invention comprises: a step where the terminal broadcasts an IP request message including a MAC address of a terminal requesting IP address allocation through the gateway; a step where the DHCP server determines whether the terminal is authorized when receiving the broadcasted IP request message; an IP address allocation step where the DHCP server allocates one IP address among the IP addresses in an authorized IP range to the terminal by transmitting a response message to the terminal if the terminal having broadcasted is an authorized terminal, or if not, allocates one IP address among the IP addresses in an unauthorized IP range to the terminal by transmitting a response message to the terminal. According to the embodiment of the present invention, the IP allocation method is capable of setting differently access rights by allocating an IP address depending on whether a terminal is authorized, thereby enhancing security. In addition, the present invention enables IP allocation to be stably carried out by using IP allocation information which is assigned previously even if there is no response from the DHCP server. Moreover, the present invention can improve convenience by an automatic scheduling function, IP allocation for each type of organization and the like.

Description

[0001] The present invention relates to an IP allocation method using a dynamic host configuration protocol,

The present invention relates to an IP allocation method using Dynamic Host Configuration Protocol (DHCP), and a DHCP IP allocation method capable of improving security, safety, and convenience.

Dynamic Host Configuration Protocol (DHCP) is a communication protocol that allows administrators in an network to manage or automate the assignment of IP addresses. In Internet Protocol (IP), every device that connects to the Internet requires a unique IP address. When a user's computer connects to the Internet, an IP address needs to be assigned to the device. The DHCP server can automatically assign IP addresses and other network information to terminals (desktop, computer, notebook, smart phone, etc.) connected to the network. That is, when the computer is plugged in elsewhere in the network, the DHCP server allows the administrator to distribute the IP address and transmit the new IP address. The DHCP server also supports static addresses for computers that include web servers that require a permanent IP address.

As shown in FIG. 1, if a DHCP server exists in the same virtual LAN as a client terminal, an IP address can be directly allocated from a DHCP server. In addition, since the DHCP request is broadcasted, if the DHCP server exists in another VLAN, the server can not be discovery. In this case, as shown in FIG. 2, a request of a terminal, which is a client, may be transmitted to a DHCP server through a router or a gateway.

However, IP allocation in the existing DHCP service has the following problems.

First, there is a problem with security. When the DHCP service is connected to the network, the IP address is allocated without any restriction, and thus, the security may be a problem. Also, due to the nature of the dynamic IP address environment, the IP address can be continuously changed.

Second, there is a problem with stability. The DHCP service has a problem in that a plurality of terminals connected to the DHCP server by allocating IP from the DHCP server in case of failure cause the network to become unusable.

Third, it is inconvenient for convenience. Because the DHCP service automatically assigns IP addresses, systematic allocation of IP addresses is difficult.

Korean Patent Laid-Open No. 10-2007-0039136

SUMMARY OF THE INVENTION It is an object of the present invention to provide an IP allocation method for improving security in IP allocation in a DHCP service. Also, the technical problem of the present invention is to improve stability and convenience in IP allocation in DHCP service.

A method of allocating an IP address using a dynamic host configuration protocol in which a DHCP server and a terminal allocate an IP address in a virtual LAN (VLAN) connected through a gateway, the method comprising the steps of: Broadcasting an IP request message including the MAC address of the second terminal through the gateway; Determining whether the terminal is an authorized terminal when the DHCP server receives the broadcasting IP request message; When the broadcasting terminal is an authorized terminal, the DHCP server allocates any IP address among IP addresses in the approved IP range and transmits the IP address to the terminal as a response message. If the broadcasting terminal is not an authorized terminal, And an IP address assignment process of assigning any one of IP addresses in the IP address to the terminal and transmitting the IP address as a response message to the terminal.

Wherein the step of determining whether the terminal is an authorized terminal comprises the steps of the DHCP server extracting a MAC address from the broadcasted IP request message; Determining that the MAC address is an authorized terminal when the MAC address exists in the grant terminal list database and determining that the terminal is not an authorized terminal if the MAC address does not exist in the grant terminal list database; have.

And the DHCP server creates an authorized terminal list database for each virtual LAN (VLAN) unit.

After the IP address assignment process, the terminal accesses the network using the assigned IP address. When the terminal having the IP address in the unapproved IP range accesses the gateway, the gateway assigns the IP address to the DHCP server And may not allow access to other networks.

In the IP address assignment process, the DHCP server can assign an IP address according to the type of the terminal requesting the organization information and the IP address assignment.

After the IP address assignment process, the terminal may store an IP allocation information storing an assigned IP address, a gateway address, a subnet mask address, and a DNS address as IP allocation information.

Broadcasting the IP request message requesting the IP address allocation through the gateway when requesting the IP reallocation after storing the IP allocation information; And accessing the network using the IP address, the gateway address, the subnet mask address, and the DNS address stored in the stored IP allocation information when there is no response from the DHCP server until the preset number of times of broadcasting is reached can do.

In the case where the terminal is an authorized terminal in the IP address assignment process, the assignment of any one of the IP addresses in the approved IP range means that, when the approved terminal has a reserved reserved IP address in the approved IP range, Determining whether the period has expired; And allocating the reserved IP address when the reservation period has not expired and randomly extracting and assigning any one of the IP addresses in the approved IP range when the reservation period has expired .

According to the embodiment of the present invention, an access right can be set differently by assigning an IP address according to whether the terminal is an approval terminal, thereby improving security. According to the embodiment of the present invention, even if there is no response from the DHCP server, it is possible to perform stable IP allocation by using previously allocated IP allocation information. Also, according to the embodiment of the present invention, convenience can be improved through automatic reservation function, IP allocation by organization type, and the like.

1 is a diagram illustrating a direct IP allocation between a terminal and a DHCP server;
FIG. 2 is a diagram illustrating IP allocation through a relay of a gateway between a terminal and a DHCP server. FIG.
3 is a system diagram illustrating a DHCP service in which an authorized terminal and an unapproved terminal are assigned an IP address according to an exemplary embodiment of the present invention.
FIG. 4 is a diagram illustrating a network connection state between an authorization terminal and an unauthorized terminal according to an embodiment of the present invention; FIG.
FIG. 5 is a diagram illustrating a state in which an authorization terminal moves to an unapproved terminal when a virtual LAN is moved according to an embodiment of the present invention. FIG.
6 is a table in which an IP address allocation range is set to be different for each virtual LAN according to an embodiment of the present invention.
7 is a flowchart illustrating an IP allocation process using a dynamic host configuration protocol according to an embodiment of the present invention.
FIG. 8 is a table set up to have a unique approval IP range for each team department in the company according to an embodiment of the present invention; FIG.
9 is a flowchart illustrating a self IP allocation process according to an embodiment of the present invention.
10 is a flowchart illustrating a process of allocating a reserved IP address through an automatic reservation function according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, in order to explain the present invention in detail so that those skilled in the art can easily carry out the present invention. . Other objects, features, and operational advantages of the present invention, including its effects and advantages, will become more apparent from the description of the preferred embodiments. It should be noted that the same reference numerals are used to denote the same or similar components in the drawings.

3 is a system diagram illustrating a DHCP service in which an authorized terminal and an unapproved terminal are assigned IP addresses according to an exemplary embodiment of the present invention.

The terminal 100 is a client terminal capable of network communication such as a desktop, a computer, a notebook, and a smart phone, and is a client terminal capable of accessing the Internet through an Internet access protocol such as a TCP / IP protocol.

The gateway 300 serves as an entrance to another network from one network, and is used to connect one network such as a LAN to another network. Each network transmits data in a protocol that is different from other networks (a promise that is predetermined in a way that processes data). If you connect directly to a network using a different protocol, you can not share data. Accordingly, one gateway 300 can construct a virtual LAN (VLAN) using the same protocol. The gateway 300 may also be implemented as a router.

For reference, a virtual LAN (VLAN) is a network network separated by a single-layer network in order to create multiple distinct broadcast domains in the network. The virtual network is configured with the maximum logical network desired by the user, To provide a means to do so. That is, a virtual LAN can be configured not by a geographical location such as a space but by an access port, a MAC address, and a protocol unit

The DHCP server 200 can automatically assign an IP address and other network information to the terminal 100 (desktop, computer, notebook, smart phone, etc.) connected to the network. That is, in the case where the computer is plugged into another place in the network, the DHCP server 200 distributes the IP address and allows to transmit a new IP address. For example, when the first terminal 110 is connected to the first port of the gateway 300, the second terminal 110 allocates and transmits to the first terminal 110 an arbitrary IP address within a predetermined range such as 192.168.0.10, When the first terminal 110 is disconnected from the first port and connected to the second port of the gateway 300, the second terminal 110 allocates an IP address again and assigns an arbitrary IP address within a predetermined range such as 192.168.0.21 to the first terminal 110 do.

The DHCP server 200 according to an exemplary embodiment of the present invention may increase the security of the terminal 100 when the broadcasting terminal 100 has been approved by the broadcasting terminal 100, And transmits it as a response message to the terminal 100 by assigning any one of the IP addresses in the unapproved IP range to the terminal 100 when the terminal 100 is not the authorized terminal 100.

The DHCP server 200 is provided with an authorization terminal list database in which the MAC address of the approved terminal 100 is registered and assigns any one of the IP addresses in the approved IP range to the authorization terminal registered in the authorization terminal list database And assigns any one of the IP addresses in the unapproved IP range to the unauthorized terminal not registered in the authorization terminal list database. For the sake of simplicity, the DHCP server 200 is allowed to connect only to the DHCP server 200.

For example, the first terminal 110 having the MAC address of [0000.1111.2222] is registered in the approved terminal list database as the authorized terminal 100, and the second terminal 110 having the MAC address of [0000.1111.3223] Assuming that the first terminal 110, which is an authorized terminal, broadcasts a request for an IP address, the DHCP server 200 determines whether the first terminal 110 is an unauthorized terminal 100 Allocate IP addresses in the range of authorization. On the contrary, when the second terminal 120, which is an unauthorized terminal, performs broadcasting requesting an IP address, the DHCP server 200 allocates and transmits an IP address in an unauthorized range.

For example, in the case of the first terminal 110, which is an approved authorized terminal having a MAC address of [0000.1111.2222] as described in the following [Table 1], within the approval range of 192.168.0.10 to 192.168.0.254 And an IP address in the unauthorized range of 1.1.0.10 to 1.1.0.254 is assigned to the second terminal 120, which is an unauthorized terminal that has been approved.

Range type

DHCP Allocation Range
Approval Scope

192.168.0.10 to 192.168.0.254
Unapproved range

1.1.0.10 ~ 1.1.0.254

When the terminal 100 having the IP address in the unapproved IP range accesses the terminal 100 having the IP address assigned thereto as described above, the gateway 300 accesses the network using the assigned IP address. Only the connection to the DHCP server 200 is allowed and the other network connection is not allowed. The gateway 300 has information on the approved IP range and the unapproved IP range, and can determine whether or not the terminal 100 is connected to the network.

Therefore, as shown in FIG. 4, the authorized first terminal 110 is allowed to connect to another virtual LAN, and can freely access the network without a separate procedure. On the other hand, the unauthorized second terminal 120 can access only the DHCP server 200 because the use of the network is limited. Accordingly, the unauthorized second terminal 120 accesses the DHCP server 200 and applies for network use. After the approval of the administrator is completed, the unauthorized IP address is allocated to the authorized range and can use the normal network.

Meanwhile, the terminal 100 is assigned an IP address in units of virtual LANs (VLANs). As shown in FIG. 5, the first terminal 110, which has been allocated an IP address from the first virtual LAN configured as the first gateway 300a, is connected to another second virtual LAN (VANN) including the second gateway 300b, The network usage in the second virtual LAN is restricted if it is not approved in the second virtual LAN. That is, the first terminal 110 can access the network only in the range of the first virtual LAN (VLAN).

6, the first terminal 110 having a MAC address of [0000.1111.2222] is assigned a first virtual address of 192.168.0.0/24, In the LAN, an authorized terminal 100 is assigned an IP address of 192.168.0.10, which belongs to the approved range. In the second virtual LAN of 192.168.1.0/24, an unauthorized unauthorized terminal receives an IP address of 1.1.1.10 So that the network access through the second virtual LAN is limited.

In order to improve the stability, the terminal 100 stores IP allocation information including an assigned IP address, a gateway address, a subnet mask address, and a DNS address when the terminal 100 receives an address from the DHCP server 200 at least once. Thereafter, when the terminal 100 makes an IP allocation request to the DHCP server 200 and there is no response from the server a predetermined number of times or more, the virtual DHCP virtual agent responds and the terminal 100 receives the IP allocation information from the server .

Meanwhile, in order to improve convenience, the DHCP server 200 may assign the same IP address without changing the IP address, and may have a fixed IP address. The IP address assigned by the DHCP server 200 is a dynamic IP address, and one terminal 100 receives a different address each time an IP address is assigned in the same virtual LAN. However, some terminals (100) should not change the IP address for a special purpose and must always be assigned the same address as a fixed IP address. The DHCP server 200 allocates a reserved IP address when there is a reserved reserved IP address in the approved IP range in the approved terminal 100. If there is no reserved IP address, One of the IP addresses is randomly extracted and allocated.

Also, in order to improve convenience, the DHCP server 200 can allocate the range addresses differently according to the type of the terminal 100 requesting allocation of the organization information, the IP address, and the type of the member. In the case of the existing DHCP server 200, when different organizations are connected to the same virtual LAN (VLAN), IP address allocation is performed irrespective of the organization members. Normally, the addresses are received sequentially in the requested order. However, the DHCP server 200 of the present invention allocates the range addresses differentially according to the organization information connected to the approval information.

7 is a flowchart illustrating an IP allocation process using a dynamic host configuration protocol according to an embodiment of the present invention.

A method for assigning an IP address using a dynamic host configuration protocol in which a DHCP server 200 and a terminal 100 allocate an IP address in a virtual LAN connected through a gateway 300, Generates an IP request message including the MAC address of the terminal 100 requesting the IP address allocation in step S702, and then broadcasts the generated IP request message through the gateway 300 in step S704 . The MAC address is a physical address of Ethernet, which is a network model used in a LAN card, and is recorded in a read-only memory (ROM) of the LAN card in the terminal 100. [ Therefore, each terminal 100 can be identified by the assigned MAC address.

When the terminal 100 broadcasts an IP request message to an unspecified counterpart via the gateway 300, the DHCP server 200 can receive the broadcasted IP request message. Upon receiving the IP request message, the DHCP server 200 determines whether the terminal that has made the IP request is an authorized terminal.

The process of determining whether the terminal 100 is the authorized terminal 100 includes the steps of the DHCP server 200 extracting the MAC address from the broadcasted IP request message S706, It is determined whether the terminal is an authorized terminal (S708). If the MAC address exists in the previously registered authorized terminal list database (S708a), it is determined that the terminal is an authorized terminal. Otherwise, the MAC address does not exist in the authorized terminal list database If not, it is determined to be an unauthorized terminal (S708b). The approved terminal list database is a database in which the MAC addresses of the authorized terminals are registered. The MAC address of the terminal that is allowed to access the network is stored in the approved terminal list database.

The DHCP server 200 allocates any one of the IP addresses in the approved IP range to the terminal 100 and transmits the response message to the terminal 100 in step S710, If the terminal is not an authorized terminal, it has an IP address assignment process in which any one of IP addresses in an unapproved IP range is assigned and transmitted as a response message to the terminal 100 (S712).

For example, as shown in FIG. 3, the first terminal 110 having a MAC address of [0000.1111.2222] is registered as an authorized terminal in the approved terminal list database, and the MAC address of [0000.1111.3333] When the first terminal 110, which is an authorized terminal, broadcasts a request for an IP address, the DHCP server 200 determines that the second terminal 120 is an unauthorized terminal, Assigns an IP address in the range of authorization and transmits it. On the contrary, when the second terminal 120, which is an unauthorized terminal, performs broadcasting requesting an IP address, the DHCP server 200 allocates and transmits an IP address in an unauthorized range. Accordingly, in the case of the authorized first terminal 110 having the MAC address of [0000.1111.2222], the IP addresses within the approved range of 192.168.0.10 to 192.168.0.254 are allocated, and in the case of the approved second terminal 120 IP addresses within the unauthenticated range of 1.1.0.10 to 1.1.0.254 are assigned.

After the IP address assignment process as described above, the terminal 100 receives the assigned IP address (S714) and accesses the network using the received IP address (S716). At this time, In step S718, the terminal 100 having the IP address in the approved IP range is allowed to connect to the network 100 freely (S720). On the other hand, when the terminal 100 having an IP address in the unapproved IP range accesses, only the connection to the DHCP server 200 is allowed (S722), and the other network connection is not permitted. The terminal 100 having the IP address in the unapproved IP range is subjected to the network use approval procedure S724 from the DHCP server 200. [ For reference, the gateway 300 has information on the approved IP range and the unauthorized IP range, and can determine whether the terminal 100 is connected to the network.

Therefore, as shown in FIG. 4, the authorized first terminal 110 is allowed to connect to another virtual LAN, and can freely access the network without a separate procedure. On the other hand, the unauthorized second terminal 120 restricts the use of the network, accesses the HCP server first, applies for the network use, and when the administrator approval is completed, the authorized range of the IP address is allocated to use the normal network have.

Meanwhile, the authorization terminal list database may be generated for each virtual LAN (VLAN) unit. As shown in FIG. 5, when the first terminal 110, which has been assigned an IP address from the first virtual LAN, moves to another second virtual LAN (VANN) and accesses the second virtual LAN, The use of the network in the second virtual LAN is limited. That is, the first terminal 110 can access the network only in the range of the first virtual LAN (VLAN).

6, the first terminal 110 having a MAC address of [0000.1111.2222] is assigned a first virtual address of 192.168.0.0/24, In the LAN, an authorized terminal 100 is assigned an IP address of 192.168.0.10, which belongs to the approved range. In the second virtual LAN of 192.168.1.0/24, an unauthorized unauthorized terminal receives an IP address of 1.1.1.10 So that the network access through the second virtual LAN is limited.

Meanwhile, in order to improve the security and convenience, the IP address can be differentially allocated according to the type of the terminal 100 requesting the organization information and the IP address allocation in the IP address assignment process.

For example, in the case where the broadcasting terminal 100 is the authorized terminal 100, the DHCP server 200 determines whether or not the IP address of the terminal 100 has been approved according to the approval information such as the type of the terminal 100 requesting assignment of the IP address, You can assign an address. In the case of the existing DHCP server 200, when different organizations are connected to the same virtual LAN (VLAN), IP addresses are assigned irrespective of the organization members, and the addresses are sequentially received in the requested order. However, the DHCP server 200 of the present invention allocates the range addresses differentially according to the organization information connected to the approval information.

For example, as shown in FIG. 8, the publicity team of the company is set to have an approved IP range of 192.168.1.100 to 192.168.1.200, and similarly, the sales team, the development team, and the planning team can also have their own approved IP ranges . This allows each team department in the company to have a different IP address from the other team departments, thus enhancing security and systemic management.

This scheme is not only the organization information of FIG. 8, but also the following [Table 2]. As shown in [Table 3] and [Table 4], it is also possible to designate and manage a range according to the type, usage type, member type, and the like of the terminal 100.

Virtual LAN (VLAN)

Range type
Terminal type
DHCP Allocation Range

The first VLAN

Approval Scope
Desktop 192.168.0.10 to 192.168.0.50 mobile 192.168.0.51 to 192.168.0.200 laptop 192.168.0.201 to 192.168.0.254 Unapproved range ANY 1.1.0.10 ~ 1.1.0.254
The second VLAN

Approval Scope computer 192.168.1.10 ~ 192.168.1.99 mobile 192.168.1.100 to 192.168.1.200 Unapproved range ANY 1.1.1.10 ~ 1.1.1.254

Virtual LAN (VLAN)

Range type
Application type
DHCP Allocation Range

The first VLAN

Approval Scope
Business 192.168.0.10 to 192.168.0.50 For internet 192.168.0.51 to 192.168.0.200 For security 192.168.0.201 to 192.168.0.254 Unapproved range ANY 1.1.0.10 ~ 1.1.0.254
The second VLAN

Approval Scope Business 192.168.1.10 ~ 192.168.1.99 Internet 192.168.1.100 to 192.168.1.200 Unapproved range ANY 1.1.1.10 ~ 1.1.1.254

Virtual LAN (VLAN)

Range type
Member type
DHCP Allocation Range

The first VLAN

Approval Scope
visitant 192.168.0.10 to 192.168.0.50 Temple 192.168.0.51 to 192.168.0.200 Dispatcher 192.168.0.201 to 192.168.0.254 Unapproved range ANY 1.1.0.10 ~ 1.1.0.254
The second VLAN

Approval Scope visitant 192.168.1.10 ~ 192.168.1.99 Temple 192.168.1.100 to 192.168.1.200 Unapproved range ANY 1.1.1.10 ~ 1.1.1.254

Meanwhile, in order to improve the stability, when the terminal 100 receives an address from the DHCP server 200 at least once, the DHCP server 200 does not respond to the IP allocation request, So that the terminal 100 operates as if it received the IP allocation information from the DHCP server 200. [

To this end, after the process of assigning an IP address, as shown in the flowchart of FIG. 9, the terminal 100 transmits IP allocation information (IP address) to store the allocated IP address, gateway address, subnet mask address and DNS address as IP allocation information And a storing process (S902).

In the case of requesting the IP reallocation (S904) after the process of storing IP allocation information as described above, the AT 100 broadcasts an IP request message requesting the IP address allocation through the gateway 300 (S906). IP reallocation refers to a case where the terminal 100 requests to allocate an IP address when the terminal 100 is detached from the gateway 300 and reconnected or powered off and then turned back on. The IP reallocation is an operation for broadcasting an IP request message through the gateway 300 do. After that, it is determined whether the DHCP server responds (S908), and when it responds, the IP reallocation (S910) is received. However, if there is no response from the DHCP server 200 until the preset number of times of broadcasting is reached, a self-addressed IP address, a gateway address, a subnet mask address, and a DNS address stored in the stored IP allocation information IP allocation process (S912). This allows the terminal 100 to operate as if it received the IP allocation information including the IP address from the DHCP server 200 using the previously stored IP allocation information.

Meanwhile, in order to improve convenience, the DHCP server 200 may assign the same IP address without changing the IP address, and may have a fixed IP address. The IP address assigned by the DHCP server 200 is a dynamic IP address, and one terminal 100 receives a different address each time an IP address is assigned in the same virtual LAN. However, some terminals (100) should not change the IP address for a special purpose and must always be assigned the same address as a fixed IP address. The DHCP server 200 allocates a reserved IP address when there is a reserved reserved IP address in the approved IP range in the approved terminal 100. If there is no reserved IP address, One of the IP addresses is randomly extracted and allocated.

10 is a flowchart illustrating a process of assigning a reserved IP address through the automatic reservation function. The terminal 100 that has been approved in the IP address assignment process is assigned any one of the IP addresses in the approved IP range by checking whether the approved terminal 100 has a reserved IP address in the approved IP range (S1002). If there is a reserved IP address (S1002a), it is determined whether the reservation period has expired (S1004). If the reservation period has expired (S1004a), an available reservation IP address is assigned (S1006). If the reservation period expires, any one of the IP addresses in the approved IP range is randomly extracted and allocated. On the other hand, if the reservation period has not expired (S1004b), the reservation IP address is allocated (S1008).

If the reservation period expires, any one of the IP addresses in the approved IP range is randomly extracted and allocated (S1006), and it is determined whether the automatic reservation function is set (S1010). If the automatic reservation function is set , And registers the assigned IP address as a reserved IP address (S1012).

For reference, the automatic reservation function may be set differently for each terminal 100 as shown in [Table 5] below.

Virtual LAN (VLAN)

Range type
Terminal type
Automatic reservation
HCP allocation range

The first virtual LAN
Approval Scope
Desktop Yes 192.168.0.10 to 192.168.0.50 mobile no 192.168.0.51 to 192.168.0.200 laptop Yes 192.168.0.201 to 192.168.0.254 Unapproved range ANY no 1.1.0.10 ~ 1.1.0.254
The second virtual LAN

Approval Scope computer Yes 192.168.1.10 ~ 192.168.1.99 mobile no 192.168.1.100 to 192.168.1.200 Unapproved range ANY no 1.1.1.10 ~ 1.1.1.254

The embodiments of the present invention described above are selected and presented in order to facilitate the understanding of those skilled in the art from a variety of possible examples. The technical idea of the present invention is not necessarily limited to or limited to these embodiments Various changes, modifications, and other equivalent embodiments are possible without departing from the spirit of the present invention.

100: terminal 110: first terminal
120: second terminal 200: DHCP server
300: Gateway

Claims (8)

A method of assigning an IP address using a dynamic host configuration protocol in which a DHCP server and a terminal allocate an IP address in a virtual LAN (VLAN) connected through a gateway,
Broadcasting the IP request message including the MAC address of the terminal requesting the IP address allocation through the gateway;
Determining whether the terminal is an authorized terminal when the DHCP server receives the broadcasting IP request message;
The DHCP server allocates any one of the IP addresses in the approved IP range and transmits the response message to the terminal when the broadcasting terminal is an authorized terminal permitted to access the network, An IP address assignment step of assigning any one of IP addresses in an unapproved IP range to a terminal and transmitting the IP address as a response message to the terminal if the connection to the server is not an approved terminal;
/ RTI >
Wherein the step of determining whether the terminal is an authorized terminal comprises the steps of the DHCP server extracting a MAC address from the broadcasted IP request message, And determining that the terminal is an unauthorized terminal if the MAC address does not exist in the terminal list database. The DHCP server generates an authorized terminal list database for each VLAN unit and,
After the IP address assignment process, the terminal accesses the network using the assigned IP address. When the terminal having the IP address in the unapproved IP range accesses the gateway, the gateway assigns the IP address to the DHCP server And does not allow access to other networks,
In the IP address assignment process, the DHCP server allocates an IP address according to the type of the terminal requesting the organization information and the IP address assignment,
The terminal is allocated an IP address in units of virtual LANs (VLANs). A first terminal, to which an authorized IP address is allocated, is moved from a first virtual LAN configured as a first gateway to a second virtual LAN configured as a second gateway Wherein the first terminal is allowed to access the network only in the first virtual LAN range and the network usage in the second virtual LAN is restricted.
delete delete delete delete The method of claim 1, further comprising:
Wherein the terminal stores an IP address, a gateway address, a subnet mask address, and a DNS address as IP allocation information.
7. The method of claim 6, wherein when requesting the IP reallocation after the IP allocation information storage process,
Broadcasting the IP request message requesting the IP address allocation through the gateway;
Accessing a network using an IP address, a gateway address, a subnet mask address, and a DNS address stored in the stored IP allocation information when there is no response from the DHCP server until a preset number of broadcasting times is reached;
A method for assigning an IP address using a dynamic host configuration protocol.
The method as claimed in claim 1, wherein, in the case of an authorized terminal in the IP address assignment process, assigning any one of the IP addresses in the approved IP range includes:
Determining whether the reserved period has expired if the approved terminal has a reserved IP address that is already reserved in the approved IP range;
Allocating the reserved IP address when the reservation period has not expired and randomly extracting and assigning any one of the IP addresses in the approved IP range when the reservation period has expired;
A method for assigning an IP address using a dynamic host configuration protocol.

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