Specifications

Enterasys Matrix N Standalone (NSA) Series Configuration Guide 26-1
26
RADIUS Snooping Configuration
ThischapterdescribestheRADIUSSnoopingcommandsandhowtousethem.
Understanding RADIUS Snooper
RADIUSSnooper(RS)allowsanetworkmanagertomanagedownstreamconnections,whenthe
fullcomplementofEnterasys’SecureNetworkscapabilitiesisnotdeployedatthenetworkedge.
Thisallowsforthedeploymentoflessfeaturerichedgedevicestoperformbasicaccesscontrolat
thenetworkedge,whilestillprovidingcomplexuser
andservicebasedCoSprovisioning,
authorization,andusageauditingtothesession.
ManydownstreamdevicesauthenticatethelocalsessionwithaRADIUSserverthatresides
upstreamofthedistribution‐tierdevice.RADIUSrequestandresponseframesfromthesedevices
transitthedistribution‐tierdevice.TheinterceptionofthisRADIUStrafficallows
thedistribution‐
tierdevicetobuildanauthenticatedsessionfortheend‐station,asthoughitwasdirectly
connected.SessionsdetectedbyRSfunctionidenticallytolocalauthenticatedsessions fromthe
perspectiveoftheEnterasysMultiAuthframework.
TheunencryptedtrafficofthedownstreamdevicespassesthroughthedevicerunningRS,
allowing
suchMultiAuthandSecureNetworkfeaturesassession‐timeout,idle‐timeout,filter‐ID
attributesandVLAN‐tunnelattributestobeappliedtothetraffic.
TheclientsendsaRADIUSAccess‐RequestframetotheRADIUSservertoinitiatethe
authenticationprocess.ThisrequestframecontainstheCalling‐Station‐IDattribute.TheCalling
‐
Station‐ID,containingtheMACaddress,iscapturedbytheRS.Thesessionisdefinedbythe
attributesreturnedbytheRADIUSserverintheAccess‐Acceptframe.Theidle‐timeoutand
session‐timeoutdictatetheendofthesession,justasifthesessionwasdirectlyconnectedtothe
distributed‐tierdevicerunningRS.
TheRSflowtablecontainsflowsforeachvalidsessionforthissystem.TheclientIPaddressand
authenticatingRADIUSserverIP addressaremanuallyenteredintotheRADIUSflowtableonthe
RSenabledswitch.WhenaninvestigatedRADIUSframetransitstheRSenabledport
witha
matchintheflowtable,asessioniscreated.Thesessionbecomesactivewhenitseesaresponsefor
thesessionmatchfromtheRADIUSserver.
Aconfigurabletimerdeterminestheamountoftimethefirmwarewillwaitbeforeterminatinga
sessionbecausenoresponsewasseenfromthe
RADIUSserver.
DefaultandnetworkadministratorconfigurableRADIUSpacketdropsettingsexistbasedupon
resourceissuesandvalidationfailure.Packetdropforvalidationfailurescanbeconfiguredona
port‐by‐portbasis.
ToconfigureRSonaswitch:
Note: An Enterasys Feature Guide document that contains a complete discussion on RADIUS
Snooping configuration exists at the following Enterasys web site: http://www.enterasys.com/
support/manuals/