Changeoption82
option82 时间:2021-04-04 阅读:()
2009InfosysTechnologiesLimitedSANOGXIV2009InfosysTechnologiesLimitedSANOGXIVTacklingSpoofingAttacksinBroadbandAccessNetworksBharatJoshi(bharat_joshi@infosys.
com)PavanKurapati(pavan_kurapati@infosys.
com)RamakrishnaRaoDTV(ramakrishnadtv@infosys.
com)2009InfosysTechnologiesLimitedSANOGXIVAgendaSpoofing–What,WhyandHowTypesofuserconnectionsinBroadbandAccessConcentratorsTypesofspoofingHowtocollectdatatodoAnti-spoofinginAccessNetworkAnti-spoofingHowtorecoveranti-spoofingdataafterBACcrash/reboot2009InfosysTechnologiesLimitedSANOGXIVWhatisSpoofiingSpoofingisaprocesswherebyoneentitymasqueradesasanotherentityWhyisspoofingdoneSpoofingAbyBisdoneforvariouspurposesBseekstheprivilegesofABintendstohideitstracksAsanattackonAHowisspoofingdoneWeshallseeincomingslides2009InfosysTechnologiesLimitedSANOGXIVTheultimategoalofspoofingUnauthorizedServiceGetserviceonsomeoneelse'sexpenseLossofServiceonTargetMakesurethatthetargetdoesnotgetanyserviceDifficulttotracetheattackerMakesurethatpeoplecannotfindwhoattackedthem.
UnnecessarypacketscloggingthenetworkMakesurethatnobodygetsagoodservice.
SecondaryvictimPrimarytargetrespondstospoofpacketandoverwhelmthesourcewhichbecomessecondaryvictim.
2009InfosysTechnologiesLimitedSANOGXIVTypesofuserconnectionsforanIPbasedDSLAMBridgedIPRoutingRFC2684basedbridgedencapsulationbetweenEndUserandDSLAMDSLAMinroutingmodewithroutedVLANsconfiguredonuplinki/fDynamicIPallocationusingDHCPPPPoE/APPPterminationinDSLAMIPallocationfromlocalpoolDSLAMinroutingmodewithroutedVLANsconfiguredonuplinki/fIPoARFC2684basedroutedencapsulationbetweenEndUserandDSLAMDSLAMinroutingmodewithroutedVLANsconfiguredonuplinki/fDynamicIPallocationusingDHCPL3DSLAMxDSLHomeHubxDSLHomeHubMPLSCloudPEPRouterPRouterBRASL3n/wDataCenterL3DSLAMInternetservices2009InfosysTechnologiesLimitedSANOGXIV6DSLAML3AxDSLHomeHubL3n/wDHCP2UnicastDISCOVER+Option82populatedwithRemote-ID/Circuit-ID1BroadcastDHCPDISCOVERUnicastDHCPOFFERwithoption82echoed3SendDHCPOFFERtothehostafterremovingoption8246UnicastREQUEST+Option82populatedwithRemote-ID/Circuit-ID5BroadcastDHCPREQUESTUnicastDHCPACKtotheclientwithoption827SendDHCPACKtothehostafterremovingoption828AddressallocationmechanismsforIPDSLAM–DHCP2009InfosysTechnologiesLimitedSANOGXIVTypesofuserconnectionsforaLayer2DSLAM1:1VLANsMapeveryuserconnectiontooneunique802.
1qbasedVLANNoneedofanyMAClearningofindividualhostsDownstreamtrafficmappingdonebasedonVLANsQinQorStackedVLANsAnouterServiceVLANidentifyingaspecificserviceisaddedDownstreammappingdonebasedoncombinationofCVLANandSVLANN:1TransparentBridgedVLANsMultipleusersmappedtoacommonVLANDownstreammappingdonebasedonVLANandDstMACcombinationMAClearningisrequiredforoperationL2DSLAMxDSLHomeHubxDSLHomeHubMPLSCloudPEPRouterPRouterBRASAccessAggregationDataCenterL2DSLAMInternetservices2009InfosysTechnologiesLimitedSANOGXIV8DSLAML2RAxDSLHomeHubBRASL3RAMetroDHCP2BroadcastDISCOVER+Option82populatedwithRemote-ID/Circuit-ID1BroadcastDHCPDISCOVER3UnicastDISCOVERwith'giaddr'populatedUnicastDHCPOFFERwithoption82echoed45BroadcastDHCPOFFERwithoption82andwithout'giaddr'SendDHCPOFFERtothehostafterremovingoption8268BroadcastREQUEST+Option82populatedwithRemote-ID/Circuit-ID7BroadcastDHCPREQUEST9UnicastREQUESTwith'giaddr'populatedUnicastDHCPACKtotheclientwithoption8210SendDHCPACKtothehostafterremovingoption8211AddressallocationmechanismsforL2DSLAM–DHCP2009InfosysTechnologiesLimitedSANOGXIV9DSLAML2RAxDSLHomeHubBRASL3RAMetroDHCPRADIUSPortEnabled1EAPOLStart2IdentityRequest3IdentityResponse4IdentityDetails5EAPMD5Challenge6MD5ChallengeResponse7AuthSuccess8AuthSuccess9DHCPAuthentication&AddressallocationmechanismsforL2DSLAM–DHCP+802.
1x2009InfosysTechnologiesLimitedSANOGXIV10DSLAMxDSLHomeHubBRASMetroRADIUS2PADI+IntermediateAgentpopulatedwithRemote-ID/Circuit-ID1PADIPADO+IntermediateAgentechoed35PADR6PADR+IntermediateAgentpopulatedwithRemote-ID/Circuit-IDPADS+IntermediateAgentechoed79PPPNegotiationsAuthentication&AddressallocationmechanismsforL2DSLAM-PPPoEPADOafterremovingagentinformationoption4PADSafterremovingagentinformationoption82009InfosysTechnologiesLimitedSANOGXIVTypeofSpoofingMACSpoofingIPSpoofingARPSpoofingControlprotocolinternalheaderspoofingPPPoEsession-idspoofingDHCPchaddr,ciaddr,relay-agent-informationoptionspoofing2009InfosysTechnologiesLimitedSANOGXIV12DSLAMAttackerChangeSrcMACaddressandfloodtrafficSimulates1000sofMACaddressatfasterratexDSLMACTablemaximumlimitreachedLegitimatetrafficdroppedduetoMACtableexhaustionChangingSourceMACaddresstoanillegitimateaddressAttackerxDSLMACI/FB2A2FloodtrafficwithbothMACAandMACBMACBLegitimatetrafficblockedMACAMACspoofing2009InfosysTechnologiesLimitedSANOGXIVIPspoofingChangingSourceIPaddresstoanillegitimateaddressAttackerxDSLIPBDoSattackonIPAIPASendtrafficwithIPAandMACBRepliesfloodedtoIPA12PingofDeathServiceProvider'sNetwork2009InfosysTechnologiesLimitedSANOGXIVARPspoofingRespond/sendARPResponsewithillegitimateIPaddressABCDARP:WhoisIPB1ARPReply:IamIPB:MACA2IPMACAABATrafficflowingtohostAARPTableABCDGratuitousARP:IamIPB:MACA1IPMACAABATrafficflowingtohostAARPTableServiceProvider'sNetworkServiceProvider'sNetwork2009InfosysTechnologiesLimitedSANOGXIVDHCPHeaderDHCPHeaderspoofingOp(1)Htype(1)Hlen(1)Hops(1)Xid(4)Secs(2)Flags(2)Ciaddr(4)Yiaddr(4)Siaddr(4)Giaddr(4)Chaddr(16)Sname(64)File(128)Options(Variable)ClientIdenrtifierRelayAgentOptionDSLAMAttackerxDSLL2RAL3RADHCPServerABDHCPRelease:MACB:SrcIP:BChaddr:A2Spoof'chaddr'fieldDHCPRelease:MACB:SrcIP:BClientId:A3Spoof'ClientIdentifier'fieldDHCPRelease:MACB:SrcIP:BOption82RemoteId:A4SpoofOption82fieldChangingInternalfieldswithinDHCPheaderDHCPRelease:MACB:SrcIP:BCiaddr:A1Spoof'ciaddr'field2009InfosysTechnologiesLimitedSANOGXIVSimilarlyPPPoESession-IDfieldidentifiesauniquesession.
SpoofingthiscanalsocauseservicedisruptionPPPoEHeaderPPPoEHeaderspoofingVERTYPECODESESSION_IDLENGTHPAYLOADChangingSESSION_IDfieldinPPPoEHeaderAttackerxDSLIPBIPAPPPoEIABRAS1PADT:SESSION_ID:ASessionDisconnectedServiceProvider'sNetwork2009InfosysTechnologiesLimitedSANOGXIVAnti-spoofingWhatisanti-spoofingMechanismtoidentifyspoofingandstoppingit.
Howanti-spoofingisdoneBydroppingthespoofedpacketsHowtoidentifythespoofedpacketsByverifyingIPAddressofthereceivedpacket.
ByverifyingMACaddressofthereceivedpacket.
ByverifyingthecombinationofIPandMACaddressforagiveninterfaceByverifyingtheIPaddress,MACaddressandothersessionbasedidentificationintheprotocolheader.
2009InfosysTechnologiesLimitedSANOGXIVDatarequiredforAnti-spoofingForeachuserconnectionListofValidIPaddressesassignedListofValidMACaddressesandifpossiblethecombinationofMACandIPaddresses,TimeforwhicheachIPaddressisvalid.
2009InfosysTechnologiesLimitedSANOGXIVWhyanti-spoofinginBroadbandAccessConcentrator(BAC)BACisattherightplace:Itknowsalltherequiredinformationtodoanti-spoofing.
Anti-spoofingbecomesdifficultandlesseffectiveifitisnotdoneasnearthesourceaspossible.
Itisnotonlyimportanttodropspoofedpackets,itisimportanttodropthemasearlyaspossible.
2009InfosysTechnologiesLimitedSANOGXIVDatacollectionforAntispoofinginBAC-PPPoE1xDSLHomeHubBRASL3RAMetroRADIUS2PADIPADO34PADRPADSBACObtainSession-IDfromPADSIPMACSession-IDI/FAA1011BB1022PPPLCPPPPIPCPBACObtainIPinformationfromIPCP567PADTBACDeletethespoofingentry2009InfosysTechnologiesLimitedSANOGXIVDatacollectionforAntispoofinginBAC-DHCPxDSLHomeHubBRASL3RAMetroDHCPIPMACLeaseI/FAA2001BB120212DHCPDISCOVERDHCPOFFER34DHCPREQUESTDHCPACKBACObtainIP/MAC/LeasetimefromDHCPACKMessage6DHCPRELEASEBACRemovetheentryfromtableLeaseEXPIREBACRemovetheentryfromtable2009InfosysTechnologiesLimitedSANOGXIVDatacollectionforAntispoofinginBAC–802.
1x+DHCP1xDSLHomeHubBRASL3RAMetroDHCP2InitialEAPNegotiationsEAPAuthSuccess34DHCPMessageexchangeDHCPACKBACObtaintheMACaddressfromEAPAuthSuccessmessageIPMACLeaseI/FAA2001BB1202RADIUSBACObtainIP&LeasetimefromDHCPACKMessage2009InfosysTechnologiesLimitedSANOGXIVMACAntispoofingDSLAMAttackerAttackerxDSLMACI/FB2A1FloodtrafficwithbothMACAandMACBMACBNoImpactonAMACAMACBIPMACLeaseI/FBB1202Floodtrafficwith1000'sofSrcMACsinadditiontoMACBCompareAntispooftableanddiscardnonmatchingentriesNoMACtableExhaustion!
MACI/FB2MACTableAntiSpoofTableIPMACLeaseI/FAA2001BB1202CompareAntispooftableanddiscardnonmatchingentriesNospoofingofNeighbor'sMAC!
2009InfosysTechnologiesLimitedSANOGXIVIPAntispoofingAttackerxDSLIPBNoImpactonAIPASendtrafficwithIPAandMACB1IPMACLeaseI/FAA2001BB1202CompareIPagainstthei/finAntispooftableMetro2009InfosysTechnologiesLimitedSANOGXIVARPAntispoofingABCDARP:WhoisIPB1ARPReply:IamIPB:MACA2IPMACAABBARPTableABCDGratuitousARP:IamIPB:MACA1IPMACAABBARPTableIPMACLeaseI/FAA2001BB1202CompareIP/MACagainstthei/finAntispooftableIPMACLeaseI/FAA2001BB1202ServiceProviderN/wServiceProviderN/w2009InfosysTechnologiesLimitedSANOGXIVDHCPHeaderAntispoofingDSLAMAttackerxDSLL2RAL3RADHCPServerABDHCPRelease:MACB:SrcIP:BChaddr:A1AntiSpooffilterdiscardDHCPRelease:MACB:SrcIP:BOption82RemoteId:A3Option82fromuntrustedentity.
DiscardIPMACLeaseI/FAA2001BB1202InspectDHCPHeader&comparechaddr&ClientIDwithantispooftableAcceptDHCPwithoption82onlyifitiscomingfromtrustedentityDHCPRelease:MACB:SrcIP:BCiaddr:A2AntiSpooffilterdiscard2009InfosysTechnologiesLimitedSANOGXIVPPPoEHeaderAntispoofingAttackerxDSLIPBIPAPPPoEIABRAS1PADT:SESSION_ID:101IPMACSession-IDI/FAA1011BB1022SessionIDdoesnotmatchNoImpactonAMetro2009InfosysTechnologiesLimitedSANOGXIVLosingdatacollectedforanti-spoofingDatausedinAntispoofingcanbelostduetovariousreasonsPlannedrebootSoftwarecrashPowerfailureReplacementofsystemSoftwareupgrade2009InfosysTechnologiesLimitedSANOGXIVHowtorecoverlostdataStaticconfigurationRequiredDataisavailableintheconfiguration.
PPPoEForPPPoE,thekeep-alivetimersareconfiguredandthesessionisre-initiatediftherearenorepliestothekeep-alivemessagesDHCPDHCPdoesnothavekeepalivemechanisminplace.
DHCPhasa'leasetime'whichisusuallyinorderof'days'.
Howtorecoverfromthissituation2009InfosysTechnologiesLimitedSANOGXIVRecoveringLeaseinformationforDHCPStableStorage:NotveryusefulasnotmanyBACssupportstablestorage.
LimitederasecyclesisalsoabottleneckinthisapproachBroadcastARPs:NeedtowaitfordownstreamtraffictoarriveandinitiateARPrequests.
Willincreasethedelay.
Cannotgetthecompleteinformationinonerequest.
PronetospoofingattacksifamalicioususerrepliestotheARPrequest.
RedundantcontrollersBACcanhaveredundantcontrollersandupononecontrollercrash,theothercontrollercantakeoverwithpre-synchedleasedata.
Notsuitableforpowerfailurescenariosorforupgrades.
Havingredundantcontrollersalsoaddtohardwarecosts2009InfosysTechnologiesLimitedSANOGXIVRecoveringLeaseinformationforDHCPQuerythroughSNMP/LDAPCurrentlynostandardMIBsareavailableforDHCPleaseinformation.
BACstypicallydonotsupportSNMPclientinterfacesQueryleaseinformationfromDHCPserverSolvesmostoftheproblemsstatedabove2009InfosysTechnologiesLimitedSANOGXIVLeasequeryforDHCP(RFC4388)RFC4388introducedanewDHCPrequestLeasequerywhichaBACcanusetoqueryDHCPservertoobtainleaseinformation.
ThreetypesofqueriesaresupportedQuerybyIPaddressOnlyIPaddressispopulatedinthequerymessage.
QuerybyMACaddressOnlyMACaddressispopulatedinthequerymessage.
Ifmorethanoneleaseisavailable,thencorrespondingIPaddressesarereturnedinassociated-ipoption.
BACthengetsadditionaldatabygeneratingquerybyIPaddress.
QuerybyClientidentifierOnlyclientidentifieroptionispopulatedinthequerymessage.
Ifmorethanoneleaseisavailable,thencorrespondingIPaddressesarereturnedinassociated-ipoption.
BACthengetstheadditionaldatabyqueryingbyIPaddress.
2009InfosysTechnologiesLimitedSANOGXIVLeasequeryforDHCP(RFC4388)Threetypesofreplymessagetypesareintroduced:DHCPLEASEACTIVEWhenDHCPserverknowsaboutthequeryidentifier.
DHCPLEASEUNKNOWN:WhenDHCPserverdoesnotknowaboutthequeryidentifier.
AnAccessConcentratorcachethisinformationsothatthiscanbeusedtoavoidgeneratingLeaseQueryforthequeryidentifier.
ThisisknownasNegativeCaching.
DHCPLEASEUNASSIGNED:WhenDHCPserverdoesmanagethequeryidentifierbutnoleaseisyetassigned.
NegativeCachingisdoneforthisresponseaswell.
2009InfosysTechnologiesLimitedSANOGXIVRFC4388basedleasequery–DataDriven34DSLAMLayer3RelayAgentxDSLHomeHubServiceProviderNetworkDHCPServerM1192.
168.
1.
2T1I1M2192.
168.
1.
8T2I1MACIPLeaseI/fM1192.
168.
1.
2T1I1AntiSpoofTable123I12009InfosysTechnologiesLimitedSANOGXIVRFC4388basedleasequery–DataDriven35DSLAMLayer3RelayAgentxDSLHomeHubServiceProviderNetworkDHCPServerCRASHMACIPLeaseI/fAntiSpoofTable123I12009InfosysTechnologiesLimitedSANOGXIVRFC4388basedleasequery–DataDriven36DSLAMLayer3RelayAgentxDSLHomeHubServiceProviderNetworkDHCPServer1DataTrafficfrom192.
168.
1.
22LeaseQuerybyIPAddress3LeaseActiveM1,T1,I1MACIPLeaseI/fM1192.
168.
1.
2T1I1AntiSpoofTable4DataTrafficfrom192.
168.
1.
25123I12009InfosysTechnologiesLimitedSANOGXIVRFC4388basedleasequery–NegativeCaching37xDSLHomeHubServiceProviderNetworkDHCPServerCRASH123I12009InfosysTechnologiesLimitedSANOGXIVRFC4388basedleasequery–NegativeCaching381DataTrafficfrom192.
168.
1.
102LeaseQuerybyIPAddressNegativeCachingxDSLHomeHubServiceProviderNetworkDHCPServer123MACIPThresholdI/fM1192.
168.
1.
10T1I13LeaseUNKNOWN182.
168.
1.
10,M14I12009InfosysTechnologiesLimitedSANOGXIVRFC4388basedleasequery–NegativeCaching392DataTrafficfrom192.
168.
1.
103LeaseQuerybyIPAddressNegativeCachingxDSLHomeHubServiceProviderNetworkDHCPServer123MACIPThresholdI/fM1192.
168.
1.
10T1I14LeaseUNKNOWN182.
168.
1.
10,M1Thresholdexpired1I12009InfosysTechnologiesLimitedSANOGXIVIssueswithRFC4388basedleasequeryExistingLeasequerymechanismisdatadriven:LeasequeryisinitiatedonlywhenAccessConcentratorsreceivesdataExistingmethodsuggeststheuseofnegativecaching.
NegativeCachingconsumeslotofresourcesunderspoofattacks.
Resultsinincreasedoutagetimefortheclients.
2009InfosysTechnologiesLimitedSANOGXIVIssueswithRFC4388basedleasequery(contd.
.
)Gettingconsolidatedleaseinformationperconnectionisnotpossible:Existingmechanismdoesn'thaveanymethodstogetconsolidatedleaseinformationforalltheclientsbelongingtoaconnection/circuitMultipleclientscanresideforagivenconnection/circuit.
IfAccessconcentratorhasleaseinformationofalltheclientsforagivenconnection/circuit,anti-spoofingcanbedoneindataplane(fastpath)2009InfosysTechnologiesLimitedSANOGXIVQuerybyremote-idRemote-IDsuboptionidentifyiesaconnection/circuituniquely.
ThisisgloballyuniqueidentifierRemote-IDcanbetrustedastheyarecreatedbyRelayAgent.
AccessConcentratorneednotwaitforthetraffictoarriveandcangenerateLeaseQueryassoonasitcomesupafterareboot.
DHCPServercanprovideconsolidatedLeaseInformationforaspecificconnection/circuit.
Oncealltheleaseinformationforagivenconnection/circuitisobtained,anti-spoofingcanbedoneindataplane(fastpath).
NoneedforNegativeCaching.
2009InfosysTechnologiesLimitedSANOGXIVLeaseQuerybyRemoteId43xDSLHomeHubServiceProviderNetworkDHCPServer123M1192.
168.
1.
2T1I1M2192.
168.
1.
8T2I1M3192.
168.
1.
10T3I1MACIPLeaseI/fAntiSpoofTableI12009InfosysTechnologiesLimitedSANOGXIVLeaseQuerybyRemoteId44xDSLHomeHubServiceProviderNetworkDHCPServerCRASH123MACIPLeaseI/fAntiSpoofTableI12009InfosysTechnologiesLimitedSANOGXIVLeaseQuerybyRemoteId451LeaseQuerybyRemoteIdforI12LeaseActiveofallthreeleases*3DataTrafficfrom192.
168.
1.
8xDSLHomeHubServiceProviderNetworkDHCPServer123M1192.
168.
1.
2T1I1M2192.
168.
1.
8T2I1M3192.
168.
1.
10T3I1MACIPLeaseI/fAntiSpoofTable4DataTrafficfrom192.
168.
1.
8BACdoesnotneedtowaitforthetraffictoinitiateLQLeasequerybyremote-idresultsinobtainingcompleteinformationonagiveninterface.
NoneedofinitiatingsubsequentqueriesI1*Leaseactiveforoneleaseisreturnedfollowedbyassociated-IPoption.
ThisresultsinsubsequentquerybyIPforremainingleases2009InfosysTechnologiesLimitedSANOGXIVProtocolDetails:ServeridentifiesaLeasequerybyremote-idwhentheleasequerymessagehas:Chaddr,siaddr,Ciaddr,htype,hlenandchaddriszeroandClientidentifieroptionisnotpresentandOption82withonlyRemote-Idsub-optionispresent.
SendsaLEASEACTIVEpopulatingtheciaddrwiththeIPaddressthatwasmostrecentlyaccessedbytheclient.
AllotherIPaddressesarereturnedinAssociated-IPoption.
RelayagentthensendsaLeasequerywith"QuerybyIPAddress"foralltheadditionalIPaddressesreturnedinAssociated-ipoption.
2009InfosysTechnologiesLimitedSANOGXIVProtocolDetails:ServermayreturnaLEASEUNASSIGNEDifitknowsitmanagestheleasefortheconnectionidentifiedbyRemote-Idsub-optionbutnoleaseisassignedyet.
ServermayreturnLEASEUNKNOWNifitdoesnotknowthecorrespondingRemote-idsub-option.
2009InfosysTechnologiesLimitedSANOGXIVWhyBulkLeasequeryTraditionalleasequery(Both4388)andleasequerybyremote-idworksontheprincipleofretrievingoneleaseatatimeWhilequerybyremote-idsolvesalltheproblemsassociatedwithRFC4388basedleasequerymechanism,itstillinvolvesgeneratinghugenumberofleasequeriestogetallthepossibledataBulkleasequeryworksontheprincipleofestablishingTCPconnectionbetweenRAandServerandretrievinginformationinbulk2009InfosysTechnologiesLimitedSANOGXIVBulkLeaseQuery49DSLAMLayer3RelayAgentxDSLHomeHubServiceProviderNetworkDHCPServerMACIPAddressLeaseTimeInterfaceM1192.
168.
1.
2T1I1M2192.
168.
1.
8T2I2M3192.
168.
1.
3T2I3I1I2I32009InfosysTechnologiesLimitedSANOGXIVBulkLeaseQuery50DSLAMLayer3RelayAgentxDSLHomeHubServiceProviderNetworkDHCPServerCRASHI1I2I3MACIPLeaseI/f2009InfosysTechnologiesLimitedSANOGXIVBulkLeaseQuery51DSLAMLayer3RelayAgentxDSLHomeHubServiceProviderNetworkDHCPServerMACIPAddressLeaseTimeInterfaceM1192.
168.
1.
2T1I1M2192.
168.
1.
8T2I2M3192.
168.
1.
3T2I33DataTrafficfrom192.
168.
1.
81BulkLeaseQueryinaTCPSession2LeaseActiveofallleases4DataTrafficfrom192.
168.
1.
8LeaseinformationofallinterfacesobtainedininonequeryI1I2I32009InfosysTechnologiesLimitedSANOGXIVProtocolDetails:DSLAMLayer3RelayAgentxDSLHomeHubServiceProviderNetworkDHCPServer1TCPSession2BulkLeaseQuerywithXID23LEASEQUERYACTIVEforXID24LEASEQUERYACTIVEforXID25LEASEQUERYACTIVEforXID26LEASEQUERYDONEforXID27TCPsessionclose2009InfosysTechnologiesLimitedSANOGXIVProtocolDetails:AQuerier(TypicallyaRelayAgent)establishesaTCPconnectionwiththeserveronport67.
Twonewquerytypesareadded"QuerybyRelay-ID"whererelay-idisauniqueRelayagentIdentifier.
AllleasesallocatedthroughaspecificRelayAgent.
"QueryforallconfiguredIPs"whereallIPaddressheldbyDHCPServerirrespectiveofstateisreturned.
Inthiscase,unassignedIPaddressesarereturnedwithUNASSIGNEDstate.
Newfiltersareadded:StartandEndtimefiltercanbepassedtoretrieveleasesforwhichstatehaschangedwithinthespecifiedtime.
Otherquerytypes(QuerybyIPAddress,MACaddress,Client-IDandremote-id)arealsosupported.
2009InfosysTechnologiesLimitedSANOGXIVProtocolDetails:UponreceivingaBULKLEASEQUERY,DHCPservergeneratesastreamofLEASEACTIVEforeachleasethatfulfilsthequery.
EndofleaseforagivenqueryisindicatedbytheLEASEQUERYDONEmessage.
MultipleBulkLeasequerycanbeinitiatedoverasingleTCPconnection.
Transactionid(XID)isusedtodistinguishbetweentherepliesformultiplequeries.
2009InfosysTechnologiesLimitedSANOGXIVStandardizationandImplementationeffortsStandardizationefforts:Querybyremote-idandBulkLeaseQuerydraftisbeingstandardizedinDHCworkinggroupofIETF.
Implementationefforts:WehavecreatedaProof-Of-Conceptimplementationof'QuerybyRemote-Id'and'BulkLeaseQuery'byenhancingISCDHCPserver.
2009InfosysTechnologiesLimitedSANOGXIVReferences:S.
Bellovin,"SecurityproblemsintheTCP/IPprotocolsuite,"SIGCOMMComputerCommunicationReview,vol.
19,no.
2,pp.
32–48,1989.
R.
BeverlyandS.
Bauer,"Thespooferproject:inferringtheextentofsourceaddressfilteringontheinternet,"inSRUTI'05:Proc.
oftheStepstoReducingUnwantedTrafficontheInternet,2005.
IETFStandards:RFC2131,DynamicHostConfigurationProtocolLayer2RelayAgenthttp://www.
ietf.
org/id/draft-ietf-dhc-l2ra-04.
txthttp://www.
ietf.
org/id/draft-ietf-dhc-l2ra-extensions-01.
txtQuerybyremote-idhttp://www.
ietf.
org/id/draft-ietf-dhc-leasequery-by-remote-id-02.
txtBulkleasequeryhttp://www.
ietf.
org/id/draft-ietf-dhc-dhcpv4-bulk-leasequery-00.
txtTR-101fromBroadbandForumhttp://www.
broadband-forum.
org/technical/download/TR-101.
pdf2009InfosysTechnologiesLimitedSANOGXIV2009InfosysTechnologiesLimitedSANOGXIVThankYou
com)PavanKurapati(pavan_kurapati@infosys.
com)RamakrishnaRaoDTV(ramakrishnadtv@infosys.
com)2009InfosysTechnologiesLimitedSANOGXIVAgendaSpoofing–What,WhyandHowTypesofuserconnectionsinBroadbandAccessConcentratorsTypesofspoofingHowtocollectdatatodoAnti-spoofinginAccessNetworkAnti-spoofingHowtorecoveranti-spoofingdataafterBACcrash/reboot2009InfosysTechnologiesLimitedSANOGXIVWhatisSpoofiingSpoofingisaprocesswherebyoneentitymasqueradesasanotherentityWhyisspoofingdoneSpoofingAbyBisdoneforvariouspurposesBseekstheprivilegesofABintendstohideitstracksAsanattackonAHowisspoofingdoneWeshallseeincomingslides2009InfosysTechnologiesLimitedSANOGXIVTheultimategoalofspoofingUnauthorizedServiceGetserviceonsomeoneelse'sexpenseLossofServiceonTargetMakesurethatthetargetdoesnotgetanyserviceDifficulttotracetheattackerMakesurethatpeoplecannotfindwhoattackedthem.
UnnecessarypacketscloggingthenetworkMakesurethatnobodygetsagoodservice.
SecondaryvictimPrimarytargetrespondstospoofpacketandoverwhelmthesourcewhichbecomessecondaryvictim.
2009InfosysTechnologiesLimitedSANOGXIVTypesofuserconnectionsforanIPbasedDSLAMBridgedIPRoutingRFC2684basedbridgedencapsulationbetweenEndUserandDSLAMDSLAMinroutingmodewithroutedVLANsconfiguredonuplinki/fDynamicIPallocationusingDHCPPPPoE/APPPterminationinDSLAMIPallocationfromlocalpoolDSLAMinroutingmodewithroutedVLANsconfiguredonuplinki/fIPoARFC2684basedroutedencapsulationbetweenEndUserandDSLAMDSLAMinroutingmodewithroutedVLANsconfiguredonuplinki/fDynamicIPallocationusingDHCPL3DSLAMxDSLHomeHubxDSLHomeHubMPLSCloudPEPRouterPRouterBRASL3n/wDataCenterL3DSLAMInternetservices2009InfosysTechnologiesLimitedSANOGXIV6DSLAML3AxDSLHomeHubL3n/wDHCP2UnicastDISCOVER+Option82populatedwithRemote-ID/Circuit-ID1BroadcastDHCPDISCOVERUnicastDHCPOFFERwithoption82echoed3SendDHCPOFFERtothehostafterremovingoption8246UnicastREQUEST+Option82populatedwithRemote-ID/Circuit-ID5BroadcastDHCPREQUESTUnicastDHCPACKtotheclientwithoption827SendDHCPACKtothehostafterremovingoption828AddressallocationmechanismsforIPDSLAM–DHCP2009InfosysTechnologiesLimitedSANOGXIVTypesofuserconnectionsforaLayer2DSLAM1:1VLANsMapeveryuserconnectiontooneunique802.
1qbasedVLANNoneedofanyMAClearningofindividualhostsDownstreamtrafficmappingdonebasedonVLANsQinQorStackedVLANsAnouterServiceVLANidentifyingaspecificserviceisaddedDownstreammappingdonebasedoncombinationofCVLANandSVLANN:1TransparentBridgedVLANsMultipleusersmappedtoacommonVLANDownstreammappingdonebasedonVLANandDstMACcombinationMAClearningisrequiredforoperationL2DSLAMxDSLHomeHubxDSLHomeHubMPLSCloudPEPRouterPRouterBRASAccessAggregationDataCenterL2DSLAMInternetservices2009InfosysTechnologiesLimitedSANOGXIV8DSLAML2RAxDSLHomeHubBRASL3RAMetroDHCP2BroadcastDISCOVER+Option82populatedwithRemote-ID/Circuit-ID1BroadcastDHCPDISCOVER3UnicastDISCOVERwith'giaddr'populatedUnicastDHCPOFFERwithoption82echoed45BroadcastDHCPOFFERwithoption82andwithout'giaddr'SendDHCPOFFERtothehostafterremovingoption8268BroadcastREQUEST+Option82populatedwithRemote-ID/Circuit-ID7BroadcastDHCPREQUEST9UnicastREQUESTwith'giaddr'populatedUnicastDHCPACKtotheclientwithoption8210SendDHCPACKtothehostafterremovingoption8211AddressallocationmechanismsforL2DSLAM–DHCP2009InfosysTechnologiesLimitedSANOGXIV9DSLAML2RAxDSLHomeHubBRASL3RAMetroDHCPRADIUSPortEnabled1EAPOLStart2IdentityRequest3IdentityResponse4IdentityDetails5EAPMD5Challenge6MD5ChallengeResponse7AuthSuccess8AuthSuccess9DHCPAuthentication&AddressallocationmechanismsforL2DSLAM–DHCP+802.
1x2009InfosysTechnologiesLimitedSANOGXIV10DSLAMxDSLHomeHubBRASMetroRADIUS2PADI+IntermediateAgentpopulatedwithRemote-ID/Circuit-ID1PADIPADO+IntermediateAgentechoed35PADR6PADR+IntermediateAgentpopulatedwithRemote-ID/Circuit-IDPADS+IntermediateAgentechoed79PPPNegotiationsAuthentication&AddressallocationmechanismsforL2DSLAM-PPPoEPADOafterremovingagentinformationoption4PADSafterremovingagentinformationoption82009InfosysTechnologiesLimitedSANOGXIVTypeofSpoofingMACSpoofingIPSpoofingARPSpoofingControlprotocolinternalheaderspoofingPPPoEsession-idspoofingDHCPchaddr,ciaddr,relay-agent-informationoptionspoofing2009InfosysTechnologiesLimitedSANOGXIV12DSLAMAttackerChangeSrcMACaddressandfloodtrafficSimulates1000sofMACaddressatfasterratexDSLMACTablemaximumlimitreachedLegitimatetrafficdroppedduetoMACtableexhaustionChangingSourceMACaddresstoanillegitimateaddressAttackerxDSLMACI/FB2A2FloodtrafficwithbothMACAandMACBMACBLegitimatetrafficblockedMACAMACspoofing2009InfosysTechnologiesLimitedSANOGXIVIPspoofingChangingSourceIPaddresstoanillegitimateaddressAttackerxDSLIPBDoSattackonIPAIPASendtrafficwithIPAandMACBRepliesfloodedtoIPA12PingofDeathServiceProvider'sNetwork2009InfosysTechnologiesLimitedSANOGXIVARPspoofingRespond/sendARPResponsewithillegitimateIPaddressABCDARP:WhoisIPB1ARPReply:IamIPB:MACA2IPMACAABATrafficflowingtohostAARPTableABCDGratuitousARP:IamIPB:MACA1IPMACAABATrafficflowingtohostAARPTableServiceProvider'sNetworkServiceProvider'sNetwork2009InfosysTechnologiesLimitedSANOGXIVDHCPHeaderDHCPHeaderspoofingOp(1)Htype(1)Hlen(1)Hops(1)Xid(4)Secs(2)Flags(2)Ciaddr(4)Yiaddr(4)Siaddr(4)Giaddr(4)Chaddr(16)Sname(64)File(128)Options(Variable)ClientIdenrtifierRelayAgentOptionDSLAMAttackerxDSLL2RAL3RADHCPServerABDHCPRelease:MACB:SrcIP:BChaddr:A2Spoof'chaddr'fieldDHCPRelease:MACB:SrcIP:BClientId:A3Spoof'ClientIdentifier'fieldDHCPRelease:MACB:SrcIP:BOption82RemoteId:A4SpoofOption82fieldChangingInternalfieldswithinDHCPheaderDHCPRelease:MACB:SrcIP:BCiaddr:A1Spoof'ciaddr'field2009InfosysTechnologiesLimitedSANOGXIVSimilarlyPPPoESession-IDfieldidentifiesauniquesession.
SpoofingthiscanalsocauseservicedisruptionPPPoEHeaderPPPoEHeaderspoofingVERTYPECODESESSION_IDLENGTHPAYLOADChangingSESSION_IDfieldinPPPoEHeaderAttackerxDSLIPBIPAPPPoEIABRAS1PADT:SESSION_ID:ASessionDisconnectedServiceProvider'sNetwork2009InfosysTechnologiesLimitedSANOGXIVAnti-spoofingWhatisanti-spoofingMechanismtoidentifyspoofingandstoppingit.
Howanti-spoofingisdoneBydroppingthespoofedpacketsHowtoidentifythespoofedpacketsByverifyingIPAddressofthereceivedpacket.
ByverifyingMACaddressofthereceivedpacket.
ByverifyingthecombinationofIPandMACaddressforagiveninterfaceByverifyingtheIPaddress,MACaddressandothersessionbasedidentificationintheprotocolheader.
2009InfosysTechnologiesLimitedSANOGXIVDatarequiredforAnti-spoofingForeachuserconnectionListofValidIPaddressesassignedListofValidMACaddressesandifpossiblethecombinationofMACandIPaddresses,TimeforwhicheachIPaddressisvalid.
2009InfosysTechnologiesLimitedSANOGXIVWhyanti-spoofinginBroadbandAccessConcentrator(BAC)BACisattherightplace:Itknowsalltherequiredinformationtodoanti-spoofing.
Anti-spoofingbecomesdifficultandlesseffectiveifitisnotdoneasnearthesourceaspossible.
Itisnotonlyimportanttodropspoofedpackets,itisimportanttodropthemasearlyaspossible.
2009InfosysTechnologiesLimitedSANOGXIVDatacollectionforAntispoofinginBAC-PPPoE1xDSLHomeHubBRASL3RAMetroRADIUS2PADIPADO34PADRPADSBACObtainSession-IDfromPADSIPMACSession-IDI/FAA1011BB1022PPPLCPPPPIPCPBACObtainIPinformationfromIPCP567PADTBACDeletethespoofingentry2009InfosysTechnologiesLimitedSANOGXIVDatacollectionforAntispoofinginBAC-DHCPxDSLHomeHubBRASL3RAMetroDHCPIPMACLeaseI/FAA2001BB120212DHCPDISCOVERDHCPOFFER34DHCPREQUESTDHCPACKBACObtainIP/MAC/LeasetimefromDHCPACKMessage6DHCPRELEASEBACRemovetheentryfromtableLeaseEXPIREBACRemovetheentryfromtable2009InfosysTechnologiesLimitedSANOGXIVDatacollectionforAntispoofinginBAC–802.
1x+DHCP1xDSLHomeHubBRASL3RAMetroDHCP2InitialEAPNegotiationsEAPAuthSuccess34DHCPMessageexchangeDHCPACKBACObtaintheMACaddressfromEAPAuthSuccessmessageIPMACLeaseI/FAA2001BB1202RADIUSBACObtainIP&LeasetimefromDHCPACKMessage2009InfosysTechnologiesLimitedSANOGXIVMACAntispoofingDSLAMAttackerAttackerxDSLMACI/FB2A1FloodtrafficwithbothMACAandMACBMACBNoImpactonAMACAMACBIPMACLeaseI/FBB1202Floodtrafficwith1000'sofSrcMACsinadditiontoMACBCompareAntispooftableanddiscardnonmatchingentriesNoMACtableExhaustion!
MACI/FB2MACTableAntiSpoofTableIPMACLeaseI/FAA2001BB1202CompareAntispooftableanddiscardnonmatchingentriesNospoofingofNeighbor'sMAC!
2009InfosysTechnologiesLimitedSANOGXIVIPAntispoofingAttackerxDSLIPBNoImpactonAIPASendtrafficwithIPAandMACB1IPMACLeaseI/FAA2001BB1202CompareIPagainstthei/finAntispooftableMetro2009InfosysTechnologiesLimitedSANOGXIVARPAntispoofingABCDARP:WhoisIPB1ARPReply:IamIPB:MACA2IPMACAABBARPTableABCDGratuitousARP:IamIPB:MACA1IPMACAABBARPTableIPMACLeaseI/FAA2001BB1202CompareIP/MACagainstthei/finAntispooftableIPMACLeaseI/FAA2001BB1202ServiceProviderN/wServiceProviderN/w2009InfosysTechnologiesLimitedSANOGXIVDHCPHeaderAntispoofingDSLAMAttackerxDSLL2RAL3RADHCPServerABDHCPRelease:MACB:SrcIP:BChaddr:A1AntiSpooffilterdiscardDHCPRelease:MACB:SrcIP:BOption82RemoteId:A3Option82fromuntrustedentity.
DiscardIPMACLeaseI/FAA2001BB1202InspectDHCPHeader&comparechaddr&ClientIDwithantispooftableAcceptDHCPwithoption82onlyifitiscomingfromtrustedentityDHCPRelease:MACB:SrcIP:BCiaddr:A2AntiSpooffilterdiscard2009InfosysTechnologiesLimitedSANOGXIVPPPoEHeaderAntispoofingAttackerxDSLIPBIPAPPPoEIABRAS1PADT:SESSION_ID:101IPMACSession-IDI/FAA1011BB1022SessionIDdoesnotmatchNoImpactonAMetro2009InfosysTechnologiesLimitedSANOGXIVLosingdatacollectedforanti-spoofingDatausedinAntispoofingcanbelostduetovariousreasonsPlannedrebootSoftwarecrashPowerfailureReplacementofsystemSoftwareupgrade2009InfosysTechnologiesLimitedSANOGXIVHowtorecoverlostdataStaticconfigurationRequiredDataisavailableintheconfiguration.
PPPoEForPPPoE,thekeep-alivetimersareconfiguredandthesessionisre-initiatediftherearenorepliestothekeep-alivemessagesDHCPDHCPdoesnothavekeepalivemechanisminplace.
DHCPhasa'leasetime'whichisusuallyinorderof'days'.
Howtorecoverfromthissituation2009InfosysTechnologiesLimitedSANOGXIVRecoveringLeaseinformationforDHCPStableStorage:NotveryusefulasnotmanyBACssupportstablestorage.
LimitederasecyclesisalsoabottleneckinthisapproachBroadcastARPs:NeedtowaitfordownstreamtraffictoarriveandinitiateARPrequests.
Willincreasethedelay.
Cannotgetthecompleteinformationinonerequest.
PronetospoofingattacksifamalicioususerrepliestotheARPrequest.
RedundantcontrollersBACcanhaveredundantcontrollersandupononecontrollercrash,theothercontrollercantakeoverwithpre-synchedleasedata.
Notsuitableforpowerfailurescenariosorforupgrades.
Havingredundantcontrollersalsoaddtohardwarecosts2009InfosysTechnologiesLimitedSANOGXIVRecoveringLeaseinformationforDHCPQuerythroughSNMP/LDAPCurrentlynostandardMIBsareavailableforDHCPleaseinformation.
BACstypicallydonotsupportSNMPclientinterfacesQueryleaseinformationfromDHCPserverSolvesmostoftheproblemsstatedabove2009InfosysTechnologiesLimitedSANOGXIVLeasequeryforDHCP(RFC4388)RFC4388introducedanewDHCPrequestLeasequerywhichaBACcanusetoqueryDHCPservertoobtainleaseinformation.
ThreetypesofqueriesaresupportedQuerybyIPaddressOnlyIPaddressispopulatedinthequerymessage.
QuerybyMACaddressOnlyMACaddressispopulatedinthequerymessage.
Ifmorethanoneleaseisavailable,thencorrespondingIPaddressesarereturnedinassociated-ipoption.
BACthengetsadditionaldatabygeneratingquerybyIPaddress.
QuerybyClientidentifierOnlyclientidentifieroptionispopulatedinthequerymessage.
Ifmorethanoneleaseisavailable,thencorrespondingIPaddressesarereturnedinassociated-ipoption.
BACthengetstheadditionaldatabyqueryingbyIPaddress.
2009InfosysTechnologiesLimitedSANOGXIVLeasequeryforDHCP(RFC4388)Threetypesofreplymessagetypesareintroduced:DHCPLEASEACTIVEWhenDHCPserverknowsaboutthequeryidentifier.
DHCPLEASEUNKNOWN:WhenDHCPserverdoesnotknowaboutthequeryidentifier.
AnAccessConcentratorcachethisinformationsothatthiscanbeusedtoavoidgeneratingLeaseQueryforthequeryidentifier.
ThisisknownasNegativeCaching.
DHCPLEASEUNASSIGNED:WhenDHCPserverdoesmanagethequeryidentifierbutnoleaseisyetassigned.
NegativeCachingisdoneforthisresponseaswell.
2009InfosysTechnologiesLimitedSANOGXIVRFC4388basedleasequery–DataDriven34DSLAMLayer3RelayAgentxDSLHomeHubServiceProviderNetworkDHCPServerM1192.
168.
1.
2T1I1M2192.
168.
1.
8T2I1MACIPLeaseI/fM1192.
168.
1.
2T1I1AntiSpoofTable123I12009InfosysTechnologiesLimitedSANOGXIVRFC4388basedleasequery–DataDriven35DSLAMLayer3RelayAgentxDSLHomeHubServiceProviderNetworkDHCPServerCRASHMACIPLeaseI/fAntiSpoofTable123I12009InfosysTechnologiesLimitedSANOGXIVRFC4388basedleasequery–DataDriven36DSLAMLayer3RelayAgentxDSLHomeHubServiceProviderNetworkDHCPServer1DataTrafficfrom192.
168.
1.
22LeaseQuerybyIPAddress3LeaseActiveM1,T1,I1MACIPLeaseI/fM1192.
168.
1.
2T1I1AntiSpoofTable4DataTrafficfrom192.
168.
1.
25123I12009InfosysTechnologiesLimitedSANOGXIVRFC4388basedleasequery–NegativeCaching37xDSLHomeHubServiceProviderNetworkDHCPServerCRASH123I12009InfosysTechnologiesLimitedSANOGXIVRFC4388basedleasequery–NegativeCaching381DataTrafficfrom192.
168.
1.
102LeaseQuerybyIPAddressNegativeCachingxDSLHomeHubServiceProviderNetworkDHCPServer123MACIPThresholdI/fM1192.
168.
1.
10T1I13LeaseUNKNOWN182.
168.
1.
10,M14I12009InfosysTechnologiesLimitedSANOGXIVRFC4388basedleasequery–NegativeCaching392DataTrafficfrom192.
168.
1.
103LeaseQuerybyIPAddressNegativeCachingxDSLHomeHubServiceProviderNetworkDHCPServer123MACIPThresholdI/fM1192.
168.
1.
10T1I14LeaseUNKNOWN182.
168.
1.
10,M1Thresholdexpired1I12009InfosysTechnologiesLimitedSANOGXIVIssueswithRFC4388basedleasequeryExistingLeasequerymechanismisdatadriven:LeasequeryisinitiatedonlywhenAccessConcentratorsreceivesdataExistingmethodsuggeststheuseofnegativecaching.
NegativeCachingconsumeslotofresourcesunderspoofattacks.
Resultsinincreasedoutagetimefortheclients.
2009InfosysTechnologiesLimitedSANOGXIVIssueswithRFC4388basedleasequery(contd.
.
)Gettingconsolidatedleaseinformationperconnectionisnotpossible:Existingmechanismdoesn'thaveanymethodstogetconsolidatedleaseinformationforalltheclientsbelongingtoaconnection/circuitMultipleclientscanresideforagivenconnection/circuit.
IfAccessconcentratorhasleaseinformationofalltheclientsforagivenconnection/circuit,anti-spoofingcanbedoneindataplane(fastpath)2009InfosysTechnologiesLimitedSANOGXIVQuerybyremote-idRemote-IDsuboptionidentifyiesaconnection/circuituniquely.
ThisisgloballyuniqueidentifierRemote-IDcanbetrustedastheyarecreatedbyRelayAgent.
AccessConcentratorneednotwaitforthetraffictoarriveandcangenerateLeaseQueryassoonasitcomesupafterareboot.
DHCPServercanprovideconsolidatedLeaseInformationforaspecificconnection/circuit.
Oncealltheleaseinformationforagivenconnection/circuitisobtained,anti-spoofingcanbedoneindataplane(fastpath).
NoneedforNegativeCaching.
2009InfosysTechnologiesLimitedSANOGXIVLeaseQuerybyRemoteId43xDSLHomeHubServiceProviderNetworkDHCPServer123M1192.
168.
1.
2T1I1M2192.
168.
1.
8T2I1M3192.
168.
1.
10T3I1MACIPLeaseI/fAntiSpoofTableI12009InfosysTechnologiesLimitedSANOGXIVLeaseQuerybyRemoteId44xDSLHomeHubServiceProviderNetworkDHCPServerCRASH123MACIPLeaseI/fAntiSpoofTableI12009InfosysTechnologiesLimitedSANOGXIVLeaseQuerybyRemoteId451LeaseQuerybyRemoteIdforI12LeaseActiveofallthreeleases*3DataTrafficfrom192.
168.
1.
8xDSLHomeHubServiceProviderNetworkDHCPServer123M1192.
168.
1.
2T1I1M2192.
168.
1.
8T2I1M3192.
168.
1.
10T3I1MACIPLeaseI/fAntiSpoofTable4DataTrafficfrom192.
168.
1.
8BACdoesnotneedtowaitforthetraffictoinitiateLQLeasequerybyremote-idresultsinobtainingcompleteinformationonagiveninterface.
NoneedofinitiatingsubsequentqueriesI1*Leaseactiveforoneleaseisreturnedfollowedbyassociated-IPoption.
ThisresultsinsubsequentquerybyIPforremainingleases2009InfosysTechnologiesLimitedSANOGXIVProtocolDetails:ServeridentifiesaLeasequerybyremote-idwhentheleasequerymessagehas:Chaddr,siaddr,Ciaddr,htype,hlenandchaddriszeroandClientidentifieroptionisnotpresentandOption82withonlyRemote-Idsub-optionispresent.
SendsaLEASEACTIVEpopulatingtheciaddrwiththeIPaddressthatwasmostrecentlyaccessedbytheclient.
AllotherIPaddressesarereturnedinAssociated-IPoption.
RelayagentthensendsaLeasequerywith"QuerybyIPAddress"foralltheadditionalIPaddressesreturnedinAssociated-ipoption.
2009InfosysTechnologiesLimitedSANOGXIVProtocolDetails:ServermayreturnaLEASEUNASSIGNEDifitknowsitmanagestheleasefortheconnectionidentifiedbyRemote-Idsub-optionbutnoleaseisassignedyet.
ServermayreturnLEASEUNKNOWNifitdoesnotknowthecorrespondingRemote-idsub-option.
2009InfosysTechnologiesLimitedSANOGXIVWhyBulkLeasequeryTraditionalleasequery(Both4388)andleasequerybyremote-idworksontheprincipleofretrievingoneleaseatatimeWhilequerybyremote-idsolvesalltheproblemsassociatedwithRFC4388basedleasequerymechanism,itstillinvolvesgeneratinghugenumberofleasequeriestogetallthepossibledataBulkleasequeryworksontheprincipleofestablishingTCPconnectionbetweenRAandServerandretrievinginformationinbulk2009InfosysTechnologiesLimitedSANOGXIVBulkLeaseQuery49DSLAMLayer3RelayAgentxDSLHomeHubServiceProviderNetworkDHCPServerMACIPAddressLeaseTimeInterfaceM1192.
168.
1.
2T1I1M2192.
168.
1.
8T2I2M3192.
168.
1.
3T2I3I1I2I32009InfosysTechnologiesLimitedSANOGXIVBulkLeaseQuery50DSLAMLayer3RelayAgentxDSLHomeHubServiceProviderNetworkDHCPServerCRASHI1I2I3MACIPLeaseI/f2009InfosysTechnologiesLimitedSANOGXIVBulkLeaseQuery51DSLAMLayer3RelayAgentxDSLHomeHubServiceProviderNetworkDHCPServerMACIPAddressLeaseTimeInterfaceM1192.
168.
1.
2T1I1M2192.
168.
1.
8T2I2M3192.
168.
1.
3T2I33DataTrafficfrom192.
168.
1.
81BulkLeaseQueryinaTCPSession2LeaseActiveofallleases4DataTrafficfrom192.
168.
1.
8LeaseinformationofallinterfacesobtainedininonequeryI1I2I32009InfosysTechnologiesLimitedSANOGXIVProtocolDetails:DSLAMLayer3RelayAgentxDSLHomeHubServiceProviderNetworkDHCPServer1TCPSession2BulkLeaseQuerywithXID23LEASEQUERYACTIVEforXID24LEASEQUERYACTIVEforXID25LEASEQUERYACTIVEforXID26LEASEQUERYDONEforXID27TCPsessionclose2009InfosysTechnologiesLimitedSANOGXIVProtocolDetails:AQuerier(TypicallyaRelayAgent)establishesaTCPconnectionwiththeserveronport67.
Twonewquerytypesareadded"QuerybyRelay-ID"whererelay-idisauniqueRelayagentIdentifier.
AllleasesallocatedthroughaspecificRelayAgent.
"QueryforallconfiguredIPs"whereallIPaddressheldbyDHCPServerirrespectiveofstateisreturned.
Inthiscase,unassignedIPaddressesarereturnedwithUNASSIGNEDstate.
Newfiltersareadded:StartandEndtimefiltercanbepassedtoretrieveleasesforwhichstatehaschangedwithinthespecifiedtime.
Otherquerytypes(QuerybyIPAddress,MACaddress,Client-IDandremote-id)arealsosupported.
2009InfosysTechnologiesLimitedSANOGXIVProtocolDetails:UponreceivingaBULKLEASEQUERY,DHCPservergeneratesastreamofLEASEACTIVEforeachleasethatfulfilsthequery.
EndofleaseforagivenqueryisindicatedbytheLEASEQUERYDONEmessage.
MultipleBulkLeasequerycanbeinitiatedoverasingleTCPconnection.
Transactionid(XID)isusedtodistinguishbetweentherepliesformultiplequeries.
2009InfosysTechnologiesLimitedSANOGXIVStandardizationandImplementationeffortsStandardizationefforts:Querybyremote-idandBulkLeaseQuerydraftisbeingstandardizedinDHCworkinggroupofIETF.
Implementationefforts:WehavecreatedaProof-Of-Conceptimplementationof'QuerybyRemote-Id'and'BulkLeaseQuery'byenhancingISCDHCPserver.
2009InfosysTechnologiesLimitedSANOGXIVReferences:S.
Bellovin,"SecurityproblemsintheTCP/IPprotocolsuite,"SIGCOMMComputerCommunicationReview,vol.
19,no.
2,pp.
32–48,1989.
R.
BeverlyandS.
Bauer,"Thespooferproject:inferringtheextentofsourceaddressfilteringontheinternet,"inSRUTI'05:Proc.
oftheStepstoReducingUnwantedTrafficontheInternet,2005.
IETFStandards:RFC2131,DynamicHostConfigurationProtocolLayer2RelayAgenthttp://www.
ietf.
org/id/draft-ietf-dhc-l2ra-04.
txthttp://www.
ietf.
org/id/draft-ietf-dhc-l2ra-extensions-01.
txtQuerybyremote-idhttp://www.
ietf.
org/id/draft-ietf-dhc-leasequery-by-remote-id-02.
txtBulkleasequeryhttp://www.
ietf.
org/id/draft-ietf-dhc-dhcpv4-bulk-leasequery-00.
txtTR-101fromBroadbandForumhttp://www.
broadband-forum.
org/technical/download/TR-101.
pdf2009InfosysTechnologiesLimitedSANOGXIV2009InfosysTechnologiesLimitedSANOGXIVThankYou
- Changeoption82相关文档
- 配置option82
- truckoption82
- Multipleoption82
- 支持option82
- 招标文件项目名称:汕头大学行政楼网络设备采购项目(重招)
- 支持option82
DiyVM独立服务器：香港沙田服务器,5M带宽CN2线路,L5630*2/16G内存/120G SSD硬盘,499元/月
diyvm怎么样?diyvm商家VPS主机均2GB内存起步，三个地区机房可选，使用优惠码后每月69元起;DiyVM独立服务器开设在香港沙田电信机房，CN2线路，5M带宽，自动化开通上架，最低499元/月，配置是L5630*2/16G内存/120G SSD硬盘。DiyVM是一家成立于2009年的国人主机商，提供的产品包括VPS主机、独立服务器租用等，产品数据中心包括中国香港、日本大阪和美国洛杉矶等，...
易探云香港云服务器价格多少钱1个月/1年?
易探云怎么样?易探云是目前国内少数优质的香港云服务器服务商家，目前推出多个香港机房的香港云服务器，有新界、九龙、沙田、葵湾等机房，还提供CN2、BGP及CN2三网直连香港云服务器。近年来，许多企业外贸出海会选择香港云服务器来部署自己的外贸网站，使得越来越多的用户会选择易探云作为网站服务提供平台。今天，云服务器网(yuntue.com)小编来谈谈易探云和易探云服务器怎么样?具体香港云服务器多少钱1个...
atcloud：480G超高防御VPS低至$4/月，美国/新加坡等6机房，512m内存/1核/500g硬盘/不限流量
atcloud主要提供常规cloud（VPS）和storage（大硬盘存储）系列VPS，其数据中心分布在美国(俄勒冈、弗吉尼亚)、加拿大、英国、法国、德国、新加坡，所有VPS默认提供480Gbps的超高DDoS防御+不限流量，杜绝DDoS攻击骚扰，比较适合海外建站等相关业务。ATCLOUD.NET是一家成立于2020年的海外主机商，主要提供KVM架构的VPS产品、LXC容器化产品、权威DNS智能解...
option82为你推荐
-
有机zz怎么看不了呢youj1zz不能看还有什么网站站酷zcool站酷zcool字体下载后怎么安装到PS中李子柒年入1.6亿李子柒男朋友是谁，李子柒父母怎么去世的？lunwenjiancepaperfree论文检测怎样算合格同ip域名两个网站同一个IP怎么绑定两个域名百度关键词分析关键词怎么分析？www.544qq.COM跪求：天时达T092怎么下载QQ99nets.com制作网络虚拟证件的网站 那里有呀？bbs2.99nets.com西安论坛、西安茶馆网、西安社区、西安bbs 的网址是多少？33tutu.comDnf绝望100鬼泣怎么过