In-depth analysis of the Broadband Router DHCP Function

DHCP functions are embodied in many places

TCP/IPEveryone knows that in a protocol-based network, each computer must have at least one IP address to communicate with other computers. In TCP/IP networks, basic network configurations are required for each workstation to be interconnected with other computers, except for IP addresses, subnet masks, default gateways, and DNS. For a small network, it may be acceptable to configure such attributes for each computer one by one, but for a large network, doing the same job for each computer is not only cumbersome, but also the absence of IP Address allocation.

DHCP can solve the above problems.

DHCP is the Dynamic Host Configuration Protocol (Dynamic Host Configuration Protocol). It aims to reduce the planning, management, and maintenance of TCP/IP networks and solve the problem of insufficient IP address space. This kind of network service facilitates the effective management of the Client IP addresses in the network.

The DHCP function is divided into two parts: one is the server, and the other is that the Client does not need to be installed, windows 9x/2000/xp starts the DHCP Client Service by default ). DHCP uses the "lease" concept to efficiently and dynamically allocate TCP/IP settings for clients. Next we will explain the allocation of dhcp ip address, and combined with the TP-LINK of Broadband Router TL-R410 specific instructionsDHCPServer.

IP Address Allocation Method of DHCP Function

The DHCP server has three IP Address allocation methods: manual allocation, automatic allocation, and dynamic allocation. Among them, dynamic allocation is the most powerful and configuration is also the most cumbersome. Currently, DHCP servers generally support several allocation methods or two of them.

Manual allocation: during manual allocation, the network administrator manually configures the IP address of the DHCP client on the DHCP server. When the DHCP client requires network services, the DHCP server passes the manually configured IP address to the DHCP client.

Automatic Allocation: in automatic allocation, you do not need to manually allocate any IP addresses. After a DHCP Client rents an IP address from the DHCP server for the first time, the IP address is permanently assigned to the DHCP Client, instead of being assigned to other clients.

Dynamic Allocation: When a DHCP Client rents an IP address from the DHCP server, the DHCP server only temporarily assigns an IP address to the client. Once the lease term expires, the address will be returned to the DHCP server for use by other clients. If the DHCP Client still needs an IP address to complete the work, you can request another IP address.

The dynamic allocation method is the only method that can automatically reuse IP addresses. It is especially convenient for DHCP clients temporarily connected to the Internet, it is also a good way to assign IP addresses to new hosts that are permanently connected to the network. The DHCP client gives up the IP address when it no longer needs it. If the DHCP client needs to shut down normally, it can release the IP address to the DHCP server, then, the DHCP server can assign the IP address to the DHCP Client requesting the IP address.

The dynamic allocation method can solve the problem of insufficient IP addresses. For example, a class C network supports only 254 hosts, and more than three hundred hosts on the network, however, if there are a maximum of 200 users online at the same time, manual or automatic allocation will not solve this problem. The IP address in the dynamic allocation mode is not always assigned to a client. If there is an idle IP address, the DHCP server can allocate it to the client with the required IP address. When the client no longer needs an IP address, the DHCP server recovers the instance.

How to Set up a DHCP server

At present, many broadband routers have the function of setting DHCP server, TP-LINK launched by the TL-410 is a Broadband Router for home users, its appearance is small, stylish. And the price is low, which is very suitable for family users and students. TL-R410 Broadband Router also supports DHCP server, with manual allocation of static IP Address Allocation) and dynamic allocation of two ways. Next we will briefly introduce how to use the TP-link TL-R410 Broadband Router as an example, set the DHCP server function.

First, go to the vrodhcp settings page and select the DHCP server. Three sub-files are displayed, including the DHCP function, client list, and static address allocation. Select the DHCP service to go to the following settings

First, enable the DHCP server, so that you can use the automatic Address Allocation Function. Address pool start address: the starting address of the IP address automatically allocated by the DHCP server. Address pool end address: the end address of the IP address automatically allocated by the DHCP server. Gateway: Optional. It is recommended that you enter the IP address of the router LAN port. The default value is 192.168.1.1. Default Domain Name: Optional. Enter the domestic network domain name. Primary DNS server: Optional. Enter the DNS server provided by the ISP. If you are not clear, contact the ISP. Backup DNS server: Optional. If the ISP provides two DNS servers, you can enter the IP address of the other DNS server here.

Note:To use the DHCP server function of the router, the TCP/IP protocol of each computer in the LAN must be set to "automatically obtain IP addresses ". This function takes effect only after the vro is restarted.

Select the client list to view the information of the client host connecting to the Internet through the vro in the local LAN, including the client host name, the client MAC address, allocated IP address, and remaining lease period. We can see that three hosts of the vro are connected to the Internet.

Lease term is an important concept. When a client uses Dynamic Address allocation, the DHCP server dynamically assigns an IP address to the client, but the assigned IP address is not always used by a client, when the DHCP server assigns an IP address to the client, it notifies the client of the validity period (that is, the lease period) of the IP address. If the client does not apply to extend the lease period after the lease period ends, the DHCP server revokes the IP address, and the remaining lease period is the time for the DHCP server to reclaim the IP address. Therefore, the customer requests to extend the lease period to the CHCP server before the lease period expires (for example, when half is left). Of course, when the client does not use this IP address, the DHCP server will be notified to reclaim the IP address, this IP address can be allocated to other clients in the future.

The TL-R410 also allows you to set static Address Allocation for DHCP servers. Select static address allocation to see the following settings. As shown in, you can obtain the MAC address of the host and assign the IP address to the host statically. In this way, the DHCP server function of the vro is fully set. For each host in the network, you only need to set it to "automatically get IP Address" in the TCP/IP protocol option. This function takes effect only after the vro is restarted. This removes the hassle of configuring cumbersome TCP/IP protocols for each host.

The DHCP function of the Broadband Router is described in detail and easy to understand. For network engineers of the new ingress, I believe the above content can help.