DHCP Design Guide

Applies To: Windows Server 2008

Dynamic Host Configuration Protocol (DHCP) enables centralized automatic management of IP addresses and other TCP/IP settings for network clients. You can reduce administrative overhead in your organization by designing and deploying a reliable and scalable DHCP solution.

DHCP terminology

The following are key DHCP concepts:

Term Description

address pool

Addresses that remain after you define a DHCP scope and apply exclusion ranges. Pooled addresses are eligible for dynamic assignment by the server to DHCP clients on your network.

exclusion range

A limited sequence of IP addresses within a scope, excluded from DHCP service offerings. Exclusion ranges assure that any addresses in these ranges are not offered by the server to DHCP clients on your network.


A length of time that a DHCP server specifies, during which a client computer can use an assigned IP address. When a lease is made to a client, the lease is active. Before the lease expires, the client typically needs to renew its address lease assignment with the server. A lease becomes inactive when it expires or is deleted at the server. The duration for a lease determines when it will expire and how often the client needs to renew it with the server.

options class

A way for the server to further manage option types provided to clients. When an options class is added to the server, clients of that class can be provided class-specific option types for their configuration. Options classes can be of two types: vendor classes and user classes.

option types

Other client configuration parameters a DHCP server can assign when serving leases to DHCP clients. For example, some commonly used options include IP addresses for default gateways (routers), WINS servers, and DNS servers. Typically, these option types are enabled and configured for each scope. You can use the DHCP console to configure default option types that are used by all scopes added and configured at the server. Most options are predefined through RFC 2132, but you can use the DHCP console to define and add custom option types, if required.


Used to create a permanent address lease assignment by the DHCP server. Reservations assure that a specified hardware device on the subnet can always use the same IP address.


The full consecutive range of possible IP addresses for a network. Scopes typically define a single physical subnet on your network to which DHCP services are offered. Scopes also provide the primary way for the server to manage distribution and assignment of IP addresses and any related configuration parameters to clients on the network.


An administrative grouping of scopes that can be used to support multiple logical IP subnets on the same physical subnet. Superscopes only contain a list of member scopes or child scopes that can be activated together. Superscopes are not used to configure other details about scope usage. For configuring most properties used within a superscope, you need to configure member scope properties individually.

About this guide

This guide is intended for use by an infrastructure specialist or system architect. The guide provides recommendations to help you plan a new DHCP deployment based on the requirements of your organization and the particular design that you want to create. It outlines the steps to take as you plan your DHCP deployment. Before you read this guide, you should have a good understanding of your organizational requirements and how DHCP works.

This guide describes one design goal, the allocating of IP addresses, and helps you determine the most appropriate address allocation method and design for your environment. You can use this guide to create a comprehensive DHCP design that meets the needs of your environment.

See Also


DHCP Deployment Design Goal: Allocating IP Addresses