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
易探云2核2G5M仅330元/年起，国内挂机宝云服务器,独立ip
易探云怎么样?易探云是国内一家云计算服务商家，致力香港服务器、国内外服务器租用及托管等互联网业务，目前主要地区为运作香港BGP、香港CN2、广东、北京、深圳等地区。目前，易探云推出深圳或北京地区的适合挂机和建站的云服务器，国内挂机宝云服务器（可选深圳或北京地区）,独立ip;2核2G5M挂机云服务器仅330元/年起！点击进入：易探云官方网站地址易探云国内挂机宝云服务器推荐：1、国内入门型挂机云服务器...
Hostodo(年付12美元)，美西斯波坎机房Linux VPS主机66折
Hostodo 商家是比较小众的国外VPS主机商，这不看到商家有推送促销优惠在美国西岸的斯波坎机房还有少部分库存准备通过低价格促销，年付低至12美元Linux VPS主机，且如果是1GB内存方案的可以享受六六折优惠，均是采用KVM架构，且可以支付宝付款。第一、商家优惠码优惠码：spokanessd 1GB+内存方案才可以用到优惠码，其他都是固定的优惠低至年12美元。第二、商家促销这里，我们可以看到...
Megalayer新加坡服务器国际带宽线路测评
前几天有关注到Megalayer云服务器提供商有打算在月底的时候新增新加坡机房，这个是继美国、中国香港、菲律宾之外的第四个机房。也有工单询问到官方，新加坡机房有包括CN2国内优化线路和国际带宽，CN2优化线路应该是和菲律宾差不多的。如果我们追求速度和稳定性的中文业务，建议还是选择CN2优化带宽的香港服务器。这里有要到Megalayer新加坡服务器国际带宽的测试服务器，E3-1230配置20M国际带...
option82为你推荐
-
摩根币摩根币是传销吗百度商城百度商城知道在哪个地方，怎么找不到啊西部妈妈网加入新疆妈妈网如何通过验证？同一ip网站同一个IP不同的30个网站，是不是在一个服务器上呢？长尾关键词挖掘工具外贸长尾关键词挖掘工具哪个好用777k7.com怎么在这几个网站上下载图片啊www.777mu.com www.gangguan23.com同一服务器网站一个服务器能运行多少个网站www.e12.com.cn上海高中除了四大名校，接下来哪所高中最好？顺便讲下它的各方面情况45gtv.comLETSCOM是什么牌子?hao.rising.cn如何解除瑞星主页锁定(hao.rising.cn). 不想用瑞星安全助手