User manual

 16‐PortGigabitEthernetPoE+Web‐ManagedSwitchwith2SFPPorts
33

6.5 F AULT /S AFETY 
6.5.1 AntiAttack
6.5.1.1 DHCPSnooping

DHCPsnoopingisasecuritytechnologybuiltintotheoperatingsystemofacapablenetworkswitchthatdropsDHCP
trafficdeterminedtobeunacceptable.ThefundamentaluseforDHCPsnoopingistopreventunauthorized(rogue)DHCP
serversofferingIPaddressestoDHCPclients.

CommandUsage
NetworktrafficmaybedisruptedwhenmaliciousDHCPmessagesarereceivedfromanoutsidesource.DHCPsnoopingis
usedtofilterDHCPmessagesreceivedonanon‐secureinterfacefromoutsidethenetworkorfirewall.WhenDHCP
snoopingisenabledgloballyandenabledonaVLANinterface,DHCPmessagesreceivedonanuntrustedinterfacefroma
devicenotlistedintheDHCPsnoopingtablewillbedropped. 
Tableentriesareonlylearnedfortrustedinterfaces.AnentryisaddedorremoveddynamicallytotheDHCPsnooping
tablewhenaclientreceivesorreleasesanIPaddressfromaDHCPserver.EachentryincludesaMACaddress,IPaddress,
leasetime,VLANidentifierandportidentifier.