Enterasys Networks DFE-Gold Series Manual

A SERVICE OF

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Enterasys Matrix DFE-Gold Series Configuration Guide 20-1

20

DHCP Configuration

ThischapterdescribestheDynamicHostConfigurationProtocol(DHCP)configurationsetof

commandsandhowtousethem.

DHCP Overview

TheDynamicHostConfigurationProtocol(DHCP)providesservicesforallocatinganddelivering

IPaddressesandotherconfigurationparameterstoInternethosts.DHCPconsistsoftwo

components:aprotocolfordeliveringhost‐specificconfigurationparametersfromaDHCPserver

toahost,andamechanismforallocatingnetworkaddressestohosts.Optional

functionalityalso

providesservicestocompletehigh‐availability,authenticatedandQoS‐dependanthost

configuration.

TheDHCPprotocolisbasedonaclient‐servermodelinwhichadesignatedDHCPserver

allocatesnetworkaddressesanddeliversconfigurationparameterstodynamicallyconfigured

clients.Throughouttheremainderofthissection,theterm“server”

referstoahostproviding

initializationparametersthroughDHCP,andtheterm“client”referstoahostrequesting

initializationparametersfromaDHCPserver.

DHCPsupportsthefollowingmechanismsforIPaddressallocation:

•Automatic—DHCPassignsanIPaddresstoaclientforalimitedperiodoftime(oruntilthe



clientexplicitlyrelinquishestheaddress).

•Manual—AclientʹsIPaddressisassignedbythenetworkadministrator,andDHCPisused

simplytoconveytheassignedaddresstotheclient.

TheamountoftimethataparticularIPaddressisvalidforasystemiscalledaleas e.The

Enterasys

Matrix‐Norstandalonedevicemaintainsaleasedatabasewhichcontainsinformation

abouteachassignedIPaddress,theMACaddresstowhichitisassigned,theleaseexpiration,and

whethertheaddressassignmentisdynamicorstatic.TheDHCPleasedatabaseisstoredinflash

memory.

Configuring DHCP

Bydefault,theDHCPserverisnotenabledontheEnterasysMatrix‐Norstandalonedevice.You

canselectivelyenableDHCPserviceonparticularinterfacesandnotothers.ToenableDHCP

serviceonaninterface,youmustfirstdefineaDHCPscope.AscopeconsistsofapoolofIP

addresses

andasetofparametersforaDHCPclient.Theparametersareusedbytheclientto

configureitsnetworkenvironment,forexample,thedefaultgatewayandDNSdomainname.

Router: Unless otherwise noted, the commands covered in this chapter can be executed only

when the device is in router mode. For details on how to enable router configuration modes, refer to

“Enabling Router Configuration Modes” on page 2-103.