What is DHCP? What is a DHCP server?

When learning network protocols, we need to pay attention to the concepts and applications of DHCP protocols and DHCP servers. So what about DHCP? Next, let's take a look at the basic concepts of DHCP.

1. What is DHCP?

Dynamic Host Allocation Protocol (DHCP) is a standard TCP/IP protocol that simplifies Host IP Address Allocation Management. You can use the DHCP server to manage dynamic IP Address Allocation and other related environment configurations, such as DNS, WINS, and Gateway settings ).

On a network that uses the TCP/IP protocol, each computer has a unique computer name and IP address. The IP address and Its subnet mask) are used to identify the host and subnet connected to the computer. When you move the computer from one subnet to another, you must change the IP address of the computer. For example, the allocation of static IP addresses will increase the burden on network administrators. DHCP allows users to dynamically allocate IP addresses in the IP address database of the DHCP server to clients in the LAN, this reduces the burden on network administrators. You can use the DHCP service provided by the Windows 2000 Server to automatically allocate IP addresses and configure related environments on the network.

When DHCP is used, the DHCP service is installed on at least one NT server in the network. Other workstations that want to use DHCP must also be set to use DHCP to obtain IP addresses. 1 shows a network instance that supports DHCP.

2. Benefits of using DHCP:

Secure and reliable settings

DHCP avoids errors caused by manual IP addresses and subnet masks. It also avoids address conflicts caused by assigning an IP address to multiple workstations. It reduces the burden of managing IP Address Settings. Using a DHCP server greatly shortens the time required to configure or reconfigure workstations in the network. At the same time, setting a DHCP server allows you to flexibly set the address rental period. At the same time, the update process of the DHCP address lease will help the user determine that the customer's settings need to be updated frequently, for example, customers who use hosts often change locations ), these changes are automatically completed by the client and the DHCP server without interference from the network administrator.

3. Common DHCP terms

Scope

A range is a continuous range of all allocable IP addresses in a network. The scope is mainly used to define the IP address range of a single physical subnet in the network. Scope is the main means for servers to manage IP addresses assigned to network customers.

Super Scope

A super scope is a set of scopes used to implement multiple logical IP subnets in the same physical subnet. A super scope contains only a list of member scopes or subscopes. However, super scopes are not used to set specific scopes. Attributes of sub-scopes must be set separately.

Exclusion Scope

The exclusion range is the sequence of IP addresses not used for allocation. It ensures that the IP address in this sequence is not allocated to the client by the DHCP server.

Address pool

After the user defines the DHCP range and the exclusion range, the remaining addresses become an address pool, and the addresses in the address pool can be dynamically allocated to clients in the network.

Lease

The lease term is the length of time specified by the DHCP server. In this period, the client can use the obtained IP address. The lease is activated when the client obtains the IP address. The client needs to update the IP address Lease Before the lease expires. When the lease expires or is deleted from the server, the lease is stopped.

4 DHCP Tool

The DHCP console is the main tool for managing DHCP servers. It is added to the management tool when installing the DHCP service. On Windows 2000 server, the DHCP console is designed as a plug-in for the Microsoft Management Console (MMC), which is more closely integrated with other network management tools. In the following sections, you will learn how to use it.

After installing the DHCP server, you can use the DHCP console to perform the following basic server management functions:

Create a range, add and set the main range and Multiple scopes, view and modify the attributes of the range, activate the range or main scope, monitor the activity of the range lease,

Create reserved addresses for customers who require fixed IP addresses

Add custom default option type

Add and configure option classes defined by users or service providers

In addition, the DHCP console also has new features, such: enhanced Performance monitors, more predefined DHCP option types, support for Dynamic DNS updates for lower-level users, and monitor authorized DHCP servers on the network.