ZXR105900/5200SeriesUserManual(BasicCongurationVolume)
Routersdonotsendthereceivedbroadcastpacketfromasub-net-
worktoanotherbydefault.Buttherouterasthedefaultgateway
oftheclienthostmustsendthebroadcastpackettothesub-net-
workwheretheDHCPserverlocateswhentheDHCPserverand
clienthostarenotinthesamesub-network.Thisfunctioniscalled
DHCPrelay.
ZXR105900/5200canactasaDHCPserverorDHCPrelaytofor-
wardDHCPinformationbutitcannotusebothfunctionsatthe
sametime.
DHCPmakesIPaddressallocationmoreconvinent.Butwiththe
wideapplicationofDHCPservice,someproblemhappens.Firstly,
DHCPserviceallowsmultipleDHCPserverstobeinasubnet,which
meansthatadministratorcan’tassurethatclientdoesn’tgetIPad-
dressfromillegalDHCPserversetbysomeclientsbutonlygets
legalIPaddressfromDHCPserversetbyadministrator .Secondly,
insubnetdeployedDHCPservice,thehostwhichisdesignatedle-
galIPaddress,subnetmaskandgatewaycanaccessnetworknor-
mally.ButDHCPserverwillstillallocatethisIPaddresstoother
hostspossibly.Itwillleadtoaddresscollisionandaffectthenor-
maldistributionofIPaddress.DHCPsnoopingfunctionisenabled
forZXR105900/5200topreventbogusDHCPserverfrombeing
laidinnetwork,andinthiscase,theportconnectingtoDHCP
servermustbesettotrustedport.What’smore,dynamicARP
inspectiontechnologycanbeusedtogethertopreventillegalIP
andMACaddressbinding,thusensuringnormalassignmentofIP
addressesbyDHCPserver .
ConfiguringDHCP
ConfiguringIPPool
1.TocongureordeleteanIPpool,usethefollowingcommand.
Step
CommandFunction
1
ZXR10(config)#ippool<word>ThiscreatesIPpoolwhich
DHCPfunctionusesand
entersintoIPpoolof
correspondingname
congurationmode.
<word>IPaddresspool
name,1~16characters.
2
ZXR10(config)#noippool<word>ThisdeletesIPaddresspool
whichnamecorresponds.
2.Tocongureconicttimeinippoolordeletetheorginalcon-
guration,usethefollowingcommands.
84CondentialandProprietaryInformationofZTECORPORATION