Enterasys Matrix DFE-Gold Series Configuration Guide 20-1
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DHCP Configuration

ThischapterdescribestheDynamicHostConfigurationProtocol(DHCP)configurationsetof
commandsandhowtousethem.

DHCP Overview

TheDynamicHostConfigurationProtocol(DHCP)providesservicesforallocatinganddelivering
IPaddressesandotherconfigurationparameterstoInternethosts.DHCPconsistsoftwo
components:aprotocolfordeliveringhostspecificconfigurationparametersfromaDHCPserver
toahost,andamechanismforallocatingnetworkaddressestohosts.Optionalfunctionalityalso
providesservicestocompletehighavailability,authenticatedandQoSdependanthost
configuration.
TheDHCPprotocolisbasedonaclientservermodelinwhichadesignatedDHCPserver
allocatesnetworkaddressesanddeliversconfigurationparameterstodynamicallyconfigured
clients.Throughouttheremainderofthissection,theterm“serverreferstoahostproviding
initializationparametersthroughDHCP,andtheterm“client”referstoahostrequesting
initializationparametersfromaDHCPserver.
DHCPsupportsthefollowingmechanismsforIPaddressallocation:
•AutomaticDHCPassignsanIPaddresstoaclientforalimitedperiodoftime(oruntilthe
clientexplicitlyrelinquishestheaddress).
•ManualAclientʹsIPaddressisassignedbythenetworkadministrator,andDHCPisused
simplytoconveytheassignedaddresstotheclient.
TheamountoftimethataparticularIPaddressisvalidforasystemiscalledalease.The
EnterasysMatrixNorstandalonedevicemaintainsaleasedatabasewhichcontainsinformation
abouteachassignedIPaddress,theMACaddresstowhichitisassigned,theleaseexpiration,and
whethertheaddressassignmentisdynamicorstatic.TheDHCPleasedatabaseisstoredinflash
memory.

Configuring DHCP

Bydefault,theDHCPserverisnotenabledontheEnterasysMatrixNorstandalonedevice.You
canselectivelyenableDHCPserviceonparticularinterfacesandnotothers.ToenableDHCP
serviceonaninterface,youmustfirstdefineaDHCPscope.AscopeconsistsofapoolofIP
addressesandasetofparametersforaDHCPclient.Theparametersareusedbytheclientto
configureitsnetworkenvironment,forexample,thedefaultgatewayandDNSdomainname.
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.