Overview of DHCP Clients and Servers

Configuring DHCP servers for a network provides these benefits:

• The administrator can centrally define global and subnet TCP/IP parameters for the entire internetwork and define parameters for reserved clients.
• Client computers do not require manual TCP/IP configuration. When a client computer moves between subnets, it is reconfigured for TCP/IP automatically at system startup time.

DHCP uses a client-server model. The network administrator establishes one or more DHCP servers that maintain TCP/IP configuration information to be provided to clients that make requests.

The DHCP server database includes the following items:

• Valid configuration parameters for all clients on the internetwork.
• Valid IP addresses maintained in a pool for assignment to clients, plus reserved addresses for manual assignment.
• Duration of leases and other configuration parameters offered by the server. The lease defines the length of time for which the assigned IP address can be used.

A Windows NT computer becomes a DHCP client if the Enable Automatic DHCP Configuration option is checked in the Windows NT TCP/IP Installation Options dialog box. When a DHCP client computer is started, it communicates with a DHCP server to receive the required TCP/IP configuration information. This configuration information includes at least an IP address and submask plus the lease associated with the configuration.

Note DHCP client software is part of the Microsoft TCP/IP-32 for Windows for Workgroups software and the Microsoft Network Client 2.0 software that are included on the Windows NT Server compact disc. For information about installing this software, see the Windows NT Server Installation Guide.

For an overview of how DHCP works, see "Dynamic Host Configuration Protocol" in Chapter 12, "Networking Concepts for TCP/IP."

Note DHCP can be monitored using SNMP. For a list of DHCP MIB object types, see Appendix A, "MIB Object Types for Windows NT."