KR100377628B1 - Implementation method of simultaneously working DHCP server and BOOTP relay agent - Google Patents

Abstract

The present invention relates to a method for enabling a router to simultaneously use a DHCP server and a BOOTP forwarding agent. According to the present invention, a method for simultaneously operating a DHCP server and a BOOTP forwarding agent includes: receiving a broadcast packet from a client; Checking whether a destination port of the packet is a port to which the DHCP server module and the BOOTP forwarding agent are identically connected; Confirming whether the DHCP server module and the BOOTP delivery agent module are operating at the same time when they are the same port; When the DHCP server module and the BOOTP delivery agent is operating at the same time, the broadcast packet is replicated to the DHCP server and the BOOTP delivery agent, characterized in that it comprises a step of processing each packet.

According to the present invention, it is expected that the DHCP server module and the BOOTP delivery agent module can be used to both the DHCP server module and the BOOTP delivery agent module by introducing an algorithm capable of simultaneously delivering broadcast packets.

Description

{Implementation method of simultaneously working DHCP server and BOOTP relay agent}

The present invention provides a method for simultaneously using a DHCP (Dynamic Host Configuration Protocol) server and a Boot Trap Protocol (BOOTP) forwarding agent using the same User Datagram Protocol (UDP) port 67 in a router. In particular, the present invention relates to a method of simultaneously operating a DHCP server and a BOOTP forwarding agent that enables a DHCP server and a BOOTP forwarding agent to operate simultaneously.

BOOTP is a protocol that allows network users to have an operating system configured automatically (get an IP address) and booted without user intervention. It was developed to automatically assign and manage configuration information of devices that do not have a hard disk, such as the X terminal. The BOOTP server, managed by the network administrator, automatically assigns IP addresses for a period of time.

BOOTP is the foundation of DHCP, a more advanced network management protocol.

In general, DHCP is a protocol that automatically assigns various TCP / IP protocol preferences, including IP addresses, to individual clients. In particular, the DHCP server responds to requests for IP address lease from DHCP clients. It maintains a scope, a range of IP addresses, and has a message format based on the message format of BOOTP.

In other words, DHCP dynamically receives IP configuration information from the server when the client is booted, thereby saving network administrators from having to configure the network individually for each host, and at the same time assuming that not all clients are running. By allocating fewer IP addresses than the number of clients, you can efficiently use a limited number of IP addresses.

The IP address allocation method includes a dynamic allocation method and a static allocation method. In the case of dynamic allocation, when a client requests configuration information, a network administrator selects and assigns an unused IP address from a range of IP addresses previously designated by the network administrator. At this time, the DHCP server gives the user permission only for a predetermined period set by the network administrator so that the client cannot use the assigned IP address indefinitely.

In addition, in the case of static allocation, if the client requests configuration information, the network administrator checks whether the client's hardware address is present in a table of predefined IP address and hardware address pairs, and uses the IP configuration information indefinitely. It is.

FIG. 1A is a diagram illustrating the format of DHCP and BOOTP messages, and FIG. 1-A is a table illustrating the fields in the DHCP and BOOTP messages.

As shown in FIG. 1A and FIG. 1B, the format of the DHCP and BOOTP message is the first 'op' field indicating the command code message, the 'htype' field indicating the type of hardware address, and the length information of the hardware address It has a 'hlen' field and a 'hops' field containing information for setting the client to zero. The client requires a boot, the hardware type is 10mb Ethernet, and when booting through the forwarding agency, it will have information 'op = 1', 'htype = 1', 'hlen = 6', and 'hops = 1'. .

The DHCP and BOOTP messages have a 'xid' field which is execution ID information, and also have a 'secs' field and a 'flags' field.

Also, 'ciaddr', 'yiaddr', 'siaddr', 'giaddr', 'which indicate the client's IP address, partner IP address, IP address of the next server to be used in bootstrap, forwarding agent IP address, and client hardware address information. Contains the chaddr 'field.

The DHCP and BOOTP messages include a 'sname' field indicating a selected host name, a 'file' field indicating a name of a boot file, and a 'options' field having selected parameter field information.

The DHCP server and the BOOTP delivery agent analyze the message of the above format to determine the destination and operate.

FIG. 2 is a diagram showing a time-dependent flow of messages exchanged between a DHCP server and a client when allocating a new network address, and FIG. 3 is a exchange between a BOOTP server, a client and a BOOTP forwarding agent when allocating a new IP address. This is a chart showing the flow of the message to be over time.

Referring to FIG. 2, a DHCP client 200 used by a user, an IP address assigned to the client 200, and a server 1 (100) and a server 2 (300) for work are configured. In addition, the server 1 (100) is located in a different network from the client (200), and the server 2 (300) is in the same network as the client (200).

When the client 200 starts to initialize (S101) and transmits a DHCPDISCOVER (Dynamic Host Configuration Protocol Call) message to the server 1 (100) and the server 2 (300) for network operation (S102), the server 1 The server 100 and the server 2 300 search the static allocation table and the dynamic allocation table in order to allocate an IP address by DHCP.

At this time, the static allocation table is a table consisting of a combination of IP address and hardware address, the dynamic allocation table is the assignable IP address set by the network administrator.

The server 1 (100) and the server 2 (300) respectively determine the host configuration (S103), and include it in the DHCPOFFER (Dynamic Host Configuration Protocol Proposal) message and transmit it to the client 200 (S104).

At this time, the server 1 (100) transmits a DHCPOFFER message, the client 200 collects a response to the IP address allocation request transmitted from a plurality of servers (S105). The DHCPOFFER message for the IP address allocation request from the client 200 is transmitted from an unspecified plurality of servers, respectively, and the description in this case only uses the server 1 100 and the server 2 300 as shown in the drawing. To explain.

When the client 200 receives the DHCPOFFER message, the client 200 selects the configuration of the server 2 300 existing in the same network among the host configurations transmitted from the server 1 100 and the server 2 300 (S106). DHCPREQUEST (Dynamic Host Configuration Protocol Request) message is sent to the server 1 (100) and the server 2 (300) (S107), the server 1 (100) does not exist in the same network, the message that the configuration selection was not selected DHCPOFFER Included in the message and transmitted, the server 2 (300) includes a message requesting the use of the IP address due to the configuration selection in the DHCPOFFER message and transmits.

The server 2 300 accepts the configuration at the request of the client, allocates an IP address to the client 200, and receives a DHCPACK (dynamic host configuration protocol response) message indicating that the DHCPOFFER message has been normally received. (S109).

When the initialization is completed as described above (S110), the server 2 (300) and the client 200 performs a network operation, when the work of the client 200 is normally terminated (S111), the client 200 is a server By sending a DHCPRELEASE (Dynamic Host Configuration Protocol Release) message to 2 (300), the server 2 (300) releases the configuration accepted (S113).

Since the operation of the DHCP server and the client 200 is based on the broadcast packet, the server and the client must be shared in the same network sharing the same broadcast area. That is, an IP address cannot be allocated from the server 1 (100) that does not exist in the same network.

Therefore, in order for the client 200 to receive an IP address assignment from the server 1 100 that does not share the broadcast area, a BOOTP delivery agent as shown in FIG. 3 is required.

Referring to FIG. 3, a BOOTP server 400 that is a server and a client that does not share the same broadcast area, a BOOTP client 600, and a BOOTP delivery agent 500 for connecting the server and the client are configured. do.

The IP assignment and operation of the BOOTP server 400 and the BOOTP client 600 are almost similar to those described with reference to FIG. 2.

That is, when the BOOTP delivery agent starts initialization (S201), and the BOOTP client 600 transmits a DISCOVER message to request an IP allocation to the BOOTP server 400 (S202), the BOOTP server 400 Does not exist in the same network, the BOOTP delivery agent 500 transmits the DISCOVER message to the BOOTP server (S203) and transmits the message to the BOOTP server 400 (S204).

As described above, the BOOTP delivery agent 500 plays a role of transferring a command between the BOOTP client 600 and the BOOTP server 400 which assign IP in the order as shown in FIG. 2.

In addition, when receiving OFFER information including IP allocation configuration information from the BOOTP server 400 (S206), it is checked whether the IP allocation configuration information of the message is overlapped with another client using ping play, and the overlap is If not, it also serves to deliver to the BOOTP client 600.

In this case, ping play means that the BOOTP delivery agent 500 sends a ping packet to an IP address included in an OFFER message received from the BOOTP server 400, and if there is a response, the other host already uses the IP address. This means that it is overlapping. Of course, if there is no response to the ping packet, it means that there is no overlap. Therefore, the OFFER message is transmitted to the BOOTP client 600.

As shown above, a BOOTP forwarding agent generally operates in a router connecting two or more networks.

However, when the DHCP and the BOOTP forwarding agent use the same UDP port 67, the router in which the DHCP server module and the BOOTP forwarding agent module operate together has the destination port number 67 of the broadcast packet up to the UDP layer. Since only one module of the module forwards the packet, conventionally, even if the DHCP server module and the BOOTP delivery agent module are operated at the same time, there is a problem that only one module operates as a result.

In addition, it is advantageous for the client to receive a large number of request signals and select appropriate IP configuration information among them, so that even if the router provides a DHCP server function, the client can access and work with servers in other networks. The ability to do so is advantageous for DHCP network implementations.

In order to solve the above problems, the present invention is to copy the broadcast packet to the UDP layer so that the DHCP server module and the BOOTP forwarding agent module can operate at the same time, the algorithm that can be delivered to the two modules at the same time The purpose of the present invention is to provide a method of simultaneously operating a DHCP server and a BOOTP forwarding agent so that both a DHCP server module and a BOOTP forwarding agent module can be used.

1A is a diagram illustrating the format of DHCP and BOOTP messages.

1B is a table illustrating the description of fields in DHCP and BOOTP messages.

Fig. 2 is a diagram showing a flow chart of the time of messages exchanged between a DHCP server and a client when allocating a new network address.

3 is a flow chart illustrating the time-dependent flow of messages exchanged between a BOOTP server, a client and a BOOTP forwarding agent when allocating a new IP address.

4 is a flowchart illustrating a step of checking whether both a DHCP server module and a BOOTP forwarding agent module are operating in a router when a router receives a propagation packet having a UDP port 67 as a target port number according to an embodiment of the present invention.

Figure 5 is a flow chart of the steps of duplicating and sending the propagation packet to each of the two modules when the DHCP server module and the BOOTP delivery agent module operating.

6 is a flowchart of a step of confirming that the DHCP server module and the BOOTP delivery agent module have completed processing of the propagation packet, and releasing the memory allocated to the duplicated packet.

Simultaneous running method of the DHCP server and the BOOTP delivery agent according to the present invention,

Receiving, by the router, a broadcast packet from the client, and confirming whether the destination port of the packet is a port to which the DHCP server module and the BOOTP forwarding agent are identically connected;

Confirming whether the DHCP server module and the BOOTP delivery agent module are operating at the same time when they are the same port;

When the DHCP server module and the BOOTP delivery agent is operating at the same time, the broadcast packet is copied to the DHCP server and the BOOTP delivery agent, characterized in that it comprises the step of processing each packet.

Preferably, the router further comprises releasing memory allocated to the duplicated packet when the DHCP server and the BOOTP delivery agent normally process the broadcast packet.

The simultaneous operation of the DHCP server and the BOOTP delivery agent will be described with reference to the accompanying drawings.

4 is a flowchart illustrating a step of checking whether a DHCP server module and a BOOTP forwarding agent module are operating in a router when the router receives a propagation packet having a UDP port 67 as a target port number according to an embodiment of the present invention. 5 is a flow chart of the steps of duplicating and sending the propagation packet to each of the two modules when the DHCP server module and the BOOTP forwarding agent module operate, and FIG. 6 shows that the DHCP server module and the BOOTP forwarding agent module complete processing the propagation packet. A flow chart of the steps of checking and releasing memory allocated to duplicated packets.

Referring to FIG. 4 to FIG. 6, a method of simultaneously operating a DHCP server and a BOOTP delivery agent according to the present invention will be described.

First, referring to FIG. 4, when a client transmits a broadcast packet to a server for network operation, the router receives a broadcast packet transmitted by the client (S100), and transmits the broadcast packet to a destination port. Check whether the number is 67 (S200). In this case, the port number of 67 is generally a procedure of checking whether the DHCP server module and the BOOTP delivery agent module are connected to the same port.

As a result of the check, if the target port number is 67, the router checks whether the DHCP server module and the BOOTP forwarding agent module using the port 67 are operating at the same time (S300). It prepares to duplicate the broadcast packet (S400).

Next, referring to FIG. 5, when the router completes preparation for replicating the broadcast packet in step S400, replication is performed (S410), and it is checked whether replication is successfully performed (S420).

If the replication is not performed properly, the router notifies the user of the replication failure and deletes the received broadcast packet (S450).

In addition, if the replication is successfully performed, the router transmits the original broadcast packet to the DHCP server module and transmits the duplicated broadcast packet to the BOOTP delivery agent module (S430).

The DHCP server module and the BOOTP delivery agent module process the received broadcast packets, respectively (S440).

Finally, as shown in FIG. 6, the router checks whether the processing of the broadcast packet transmitted from the DHCP server module and the BOOTP delivery agent module is normally completed (S441). The memory allocated to is released (S442).

If it is not processed normally, it notifies the user and releases the memory allocated to the duplicated packet (S443).

In detail, when the client sends a DISCOVER message to the router for an IP allocation request by DHCP, the router checks the destination of the received DISCOVER message. At this time, the router first checks whether the DISCOVER message is a broadcast packet. Since the message for DHCP is a broadcast packet, the router checks the destination.

If the destination port number of the DISCOVER message is 67, the router determines whether both the DHCP server and the BOOTP forwarding agent are operating. If the DHCP server and the BOOTP forwarding agent are simultaneously running, the router duplicates the DISCOVER message. The message is sent to the DHCP server, and the duplicate message is sent to the BOOTP forwarding agent.

The DHCP server and the BOOTP delivery agent determine a configuration for IP allocation according to the DISCVER message.

At this time, the router monitors whether the DHCP server and the BOOTP forwarding agent complete the configuration decision operation according to the DISCOVER message, and when both of them complete the configuration decision operation normally, the router releases the memory allocated for the replica of the DISCOVER message. To allocate replica allocation memory for other messages.

As described above, in the method of simultaneously operating a DHCP server and a BOOTP forwarding agent according to the present invention, a broadcast packet transmitted from a client does not simultaneously transmit from a router to a DHCP server and a BOOTP forwarding agent using the same UDP port 67 at the same time. If the DHCP server and BOOTP forwarding agent were not operated at the same time, the router can replicate the broadcast packet and send it to the DHCP server and the BOOTP forwarding agent at the same time so that the DHCP server and the BOOTP forwarding agent can be used simultaneously. This has the effect of improving the performance of the router.

Claims (2)

Receiving, by the router, a broadcast packet from the client, and confirming whether the destination port of the packet is a port to which the DHCP server module and the BOOTP forwarding agent are identically connected; Confirming whether the DHCP server module and the BOOTP delivery agent module are operating at the same time when they are the same port; When the DHCP server module and the BOOTP forwarding agent are operating at the same time, the broadcast packet of the DHCP server and the BOOTP forwarding agent comprising the step of replicating the broadcast packet to each of the DHCP server and the BOOTP forwarding agent to process each packet; Simultaneous driving method. The DHCP server and the BOOTP forwarding agent of claim 1, further comprising releasing memory allocated to the duplicated packet when the DHCP server and the BOOTP forwarding agent normally process the broadcast packet. Simultaneous driving method.