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Benefits of using DHCP

DHCP provides the following benefits for administering your TCP/IP-based network:

Safe and reliable configuration

DHCP avoids configuration errors caused by the need to manually type in valuesat each computer. Also, DHCP helps prevent address conflicts caused by a

previously assigned IP address being reused to configure a new computer on the

network.

Reduces configuration management

Using DHCP servers can greatly decrease time spent configuring and

reconfiguring computers on your network. Servers can be configured to supply a

full range of additional configuration values when assigning address leases. Thesevalues are assigned using DHCP options.

Also, the DHCP lease renewal process helps assure that where client

configurations need to be updated often (such as users with mobile or portable

computers who change locations frequently), these changes can be madeefficiently and automatically by clients communicating directly with DHCP

servers.

How DHCP worksDHCP uses a client-server model. The network administrator establishes one or more

DHCP servers that maintain TCP/IP configuration information and provide it to clients.

The server database includes the following:

Valid configuration parameters for all clients on the network.

Valid IP addresses maintained in a pool for assignment to clients, plus reserved

addresses for manual assignment.

Duration of a lease offered by the server. The lease defines the length of time for

which the assigned IP address can be used.

With a DHCP server installed and configured on your network, DHCP-enabled clients

can obtain their IP address and related configuration parameters dynamically each time

they start and join your network. DHCP servers provide this configuration in the form ofan address-lease offer to requesting clients.

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ScopeAscope is the full successive range of possible IP addresses for a network. Scopes

typically define a single physical subnet on your network to which DHCP services areoffered. 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.SuperscopeAsuperscope is 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 ofmember scopes orchild 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.

Exclusion RangeAn exclusion range is 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.

Address PoolAfter you define a DHCP scope and apply exclusion ranges, the remaining addresses

form the available address poolwithin the scope. Pooled addresses are eligible fordynamic assignment by the server to DHCP clients on your network.

LeaseA lease is a length of time that a DHCP server specifies, during which a client computercan 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. Theduration for a lease determines when it will expire and how often the client needs to

renew it with the server.