Configuring MAC Locking
23-50 Authentication and Authorization Configuration
Configuring MAC Locking
ThisfeaturelocksaMACaddresstooneormoreports,preventingconnectionofunauthorized
devicesthroughtheport(s).WhensourceMACaddressesarereceivedonspecifiedports,the
switchdiscardsallsubsequentframes notcontainingtheconfiguredsourceaddresses.Theonly
framesforwardedona“locked”portarethosewith
the“locked”MACaddress(es)forthatport.
TherearetwomethodsoflockingaMACtoaport:firstarrivalandstatic.Thefirstarrivalmethod
isdefinedtobelockingthefirstnnumberofMACswhicharriveonaportconfiguredwithMAC
lockingenabled.Thevaluenis
configuredwiththesetmaclockfirstarrivalcommand.
ThestaticmethodisdefinedtobestaticallyprovisioningaMAC‐portlockusingthesetmaclock
command.ThemaximumnumberofstaticMACaddressesallowedforMAClockingonaport
canbeconfiguredwiththesetmaclockstaticcommand.
Youcanconfigure
theswitchtoissueaviolationtrapifapacketarriveswithasourceMAC
addressdifferentfromanyofthecurrentlylockedMACaddressesforthatport.
MACsareunlockedasaresultof:
•Alinkdownevent
•WhenMAClock ing isdisabledonaport
•WhenaMACisaged
outoftheforwardingdatabasewhenFirstArrivalagingisenabled
Whenproperlyconfigured,MAClockingisanexcellentsecuritytoolasitpreventsMACspoofing
onconfiguredports.AlsoifaMACweretobesecuredbysomethinglikeDragonDynamic
IntrusionDetection,MAClockingwouldmakeitmoredifficultfor
ahackertosendpacketsinto
thenetworkbecausethehackerwouldhavetochangetheir MACaddressandmovetoanother
port.Inthemeantimethesystemadministratorwouldbereceivingamaclocktrapnotification.
Purpose
Toreview,disable,enable,andconfigureMAClocking.
Commands
authenticated mac
address
If authentication has succeeded, displays the MAC address assigned for egress.
vlan id If authentication has succeeded, displays the assigned VLAN id for ingress.
Table 23-5 show vlanauthorization Output Details (Continued)
Output Field What It Displays...
For information about... Refer to page...
show maclock 23-51
show maclock stations 23-52
set maclock enable 23-53
set maclock disable 23-54
set maclock 23-54
clear maclock 23-55