Dynamic Host Configuration Protocol

DHCP Terminology

Table 4.1 lists common DHCP terms that are used throughout this chapter.

Table 4.1 DHCP Terminology

Term	Description
DHCP server	Any computer running the Windows 2000 DHCP service.
DHCP client	Any computer that has DHCP settings enabled.
Scope	The full, consecutive range of possible IP addresses for a network. DHCP services can be offered to scopes, which typically define a single physical subnet on a network. DHCP servers primarily use scopes to manage network distribution and assignment of IP addresses and any related configuration parameters.
Superscope	An administrative grouping of scopes that are used to support multiple, logical IP subnets on the same physical subnet. Superscopes contain a list of member scopes (or child scopes) that can be activated as a collection.
Exclusion range	Ensures that any IP address listed in that range is not offered by the DHCP server to any DHCP clients.
Address pool	Available IP addresses form an address pool within the scope. Pooled addresses are available for dynamic assignment by the DHCP server to DHCP clients.
Lease	The length of time, specified by the DHCP server, a client computer can use a dynamically assigned IP address. When a lease is made to a client, the lease is considered active. Before the lease expires, the client renews its lease with the DHCP server. A lease becomes inactive when it either expires or is deleted by the server. The lease duration determines when the lease expires and how often the client needs to renew its lease with the DHCP server.
Reservation	Creates a permanent address lease assignment from the DHCP server to the client. Reservations ensure that a specified hardware device on the subnet can always use the same IP address. This is useful for computers such as remote access gateways, WINS, or DNS servers that must have a static IP address.
Option types	Other client configuration parameters a DHCP server can assign when offering an IP address lease to a client. Typically, these option types are enabled and configured for each scope. Most options are predefined through RFC 2132, but you can use DHCP Manager to define and add custom option types as needed.
Option class	A way for the DHCP server to further submanage option types provided to clients. Option classes can be configured on your DHCP servers to offer specialized client support. When an option class is added to the server, clients of that class can be provided class-specific option types for their configuration.