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ConfiguringDHCPSnooping

D-Link UnifiedWiredandWirelessAccessSystem

November2011 Page253

D‐LinkUWSUserManual

TheDHCPsnoopingapplicationprocessesincomingDHCPmessages.ForDHCPRELEASEandDHCPDECLINE

messages,theapplicationcomparesthereceiveinterfaceandVLANwiththeclient’sinterfaceandVLANinthe

bindingdatabase.Iftheinterfacesdonotmatch,theapplicationlogstheeventanddropsthemessage.For

validclientmessages,DHCPsnoopingcom

paresthesourceMACaddresstotheDHCPclienthardwareaddress.

Wherethereisamismatch,DHCPsnoopinglogsanddropsthepacket.Youcandisablethisfeatureusingthe

DHCPSnoopingInterfaceConfigurationpage,showninFigure158below,orbyusingthe

noipdhcpsnooping

verifymac‐address

command.DHCPsnoopingforwardsvalidclientmessage sontrustedmemberswithinthe

VLAN.IfDHCPrelayand/orDHCPserverco‐existwiththeDHCPsnooping,theDHCPclientmessagewillbesent

totheDHCPrelayand/orDHCPservertoprocessfurther.

ToaccesstheDHCPSnoopingInterfaceConfigurationpage,clickLAN >L2Features>DH

CPSnooping>

InterfaceConfigurationinthenavigationtree.

Figure158:DHCPSnoopingInterfaceConfiguration

•ClickSubmittoapplythenewconfigurationandcausethechangetotakeeffect.Thesechangeswillnot

beretainedacrossapowercycleunlessaSaveconfigurationisperformed.

Table139:DHCPSn

oopingInterfaceConfiguration

Field Description

Interface Selecttheinterfaceforwhichdataistobedisplayedorconfigured.

TrustState Ifitisenabled,theDHCPsnoopingapplicationconsiderstheportastrusted.

ThedefaultisDisable.

LoggingInvalidPackets Ifitisenabled,theDHCPsnoopingapplicationlogsinvalidpacketsonthis

interface.Thedef aultisDisable.

teLimit SpecifiestheratelimitvalueforDHCPsnoopingpurposes.Iftheincomingrate

ofDHCPpacketsexceedsthevalueofthisobjectforconsecutivelyburst

intervalseconds,theportwillbeshutdown.IfthisvalueisNone,thereisno

limit.Thedefaultis15pack etspersecond(pps).Th

eRateLimitrangeis0to

300.

BurstInterval Specifiestheburstintervalvalueforratelimitingpurposesonthisinterface.If

theratelimitisNone,theburstintervalhasnomeaninganddisplaysitas“N/

A” .Thedefaultis1second.TheBurstIntervalrangeis1to15