宽带共享技术

广域网接入共享技术 INTERNET的各种接入方式 PSTN MODEMISDNBRIADSLISDNPRI长宽等GPRS 共享技术 PROXYSERVER代理服务器ICSNAT 连接方式 INTERNET PROXYSERVER WINGATESGATE等多种软件 NAT UseNATif YouneedtoconnecttotheInternetandyourhostsdonothavegloballyuniqueIPaddressesYouchangeovertoanewISPthatrequiresyoutorenumberyournetworkTwointranetswithduplicateaddressesmergeYouwanttosupportbasicloadsharing NATImplementationConsiderations AdvantagesConserveslegallyregisteredaddressesReducesaddressoverlapoccurrenceIncreasesflexibilitywhenconnectingtoInternetEliminatesaddressrenumberingasnetworkchanges DisadvantagesTranslationintroducesswitchingpathdelaysLossofend to endIPtraceabilityCertainapplicationswillnotfunctionwithNATenabled NATOverviewandTerminology Internet Inside 10 1 1 1 InsideLocalIP Address 10 1 1 2 10 1 1 1 SimpleNATtable InsideGlobal IPAddress 202 168 2 3 202 168 2 2 10 1 1 2 HostB 162 20 7 3 A C B A B D SA10 1 1 1 DA10 1 1 1 SA192 168 2 2 DA192 168 2 2 NATOperation InsideLocal IPAddress 10 1 1 1 10 1 1 2 NATtable InsideGlobal IPAddress 202 168 2 2 202 168 2 3 NATfunctions TranslationinsidelocaladdressesOverloadinginsideglobaladdressesTCPloaddistributionHandlingoverlappingnetworks Internet Inside 10 1 1 1 10 1 1 2 TranslatingInsideLocalAddresses 10 1 1 2 10 1 1 1 192 168 2 3 192 168 2 2 NATtable InsideLocalIPAddress InsideGlobal IPAddress 10 1 1 3 192 168 2 4 Internet Inside 10 1 1 1 10 1 1 2 HostB 172 20 7 3 1 3 SA10 1 1 1 DA10 1 1 1 SA192 168 2 2 DA192 168 2 2 10 1 1 2 10 1 1 3 4 5 2 OverloadingInsideGlobalAddresses 10 1 1 2 1723 10 1 1 1 1024 NATtable 192 168 2 2 1723 192 168 2 2 1024 172 21 7 3 23 172 20 7 3 23 TCP TCP 10 1 1 3 1723 192 168 2 2 1492 172 21 7 3 23 TCP Internet Inside 10 1 1 1 HostB 172 20 7 3 1 3 SA10 1 1 1 DA10 1 1 1 SA192 168 2 2 DA192 168 2 2 10 1 1 2 10 1 1 3 4 5 2 HostC 172 21 7 3 DA192 168 2 2 4 InsideGlobalIP Address Port OutsideGlobal IPAddress Port Protocol InsideLocalIP Address Port 10 1 1 1 TCPLoadDistribution NATtable InsideGlobalIP Address Port 10 1 1 127 80 10 1 1 127 80 10 1 1 127 80 OutsideGlobal IPAddress Port 172 20 7 3 3058 172 21 7 3 4371 172 20 7 3 3062 Protocol TCP TCP TCP InsideLocalIP Address Port 10 1 1 1 80 10 1 1 2 80 10 1 1 3 80 Internet Inside 10 1 1 1 HostB 172 20 7 3 4 5 SA10 1 1 1 DA10 1 1 1 SA10 1 1 127 DA10 1 1 127 10 1 1 2 10 1 1 1 1 3 2 HostC 172 21 7 3 10 1 1 127 10 1 1 3 Virtualhost Realhosts DynamicNATConfiguration Translatebetweeninsidehostsaddressedfrom10 1 1 0 24tothegloballyunique192 168 2 0 24network Thisinterfaceconnectedtotheoutsideworld Thisinterfaceconnectedtotheinsidenetwork ipnatpooldyn nat192 168 2 1192 168 2 254netmask255 255 255 0ipnatinsidesourcelist1pooldyn nat interfaceEthernet0ipaddress10 1 1 10255 255 255 0ipnatinside interfaceSerial0ipaddress172 16 2 1255 255 255 0ipnatoutside access list1permit10 1 1 00 0 0 255 ConfiguringInsideGlobalAddressOverloading ipnatpoolovrld nat192 168 2 1192 168 2 2netmask255 255 255 0ipnatinsidesourcelist1poolovrld natoverload interfaceEthernet0 0ipaddress10 1 1 10255 255 255 0ipnatinside interfaceSerial0 0ipaddress172 16 2 1255 255 255 0ipnatoutside access list1permit10 1 1 00 0 0 255 ConfiguringTCPLoadDistribution ipnatpoolreal hosts10 1 1 110 1 1 126prefix length24typerotaryipnatinsidedestinationlist2poolreal hosts interfaceserial0ipaddress192 168 1 129255 255 255 224ipnatoutside interfaceethernet0ipaddress10 1 1 254255 255 255 0ipnatinside access list2permit10 1 1 127 ConfiguringNATtoTranslateOverlappingAddresses ipnatpoolnet 2192 2 2 1192 2 2 254prefix length24ipnatpoolnet 1010 0 1 110 0 1 254prefix length24ipnatoutsidesourcelist1poolnet 2ipnatinsidesourcelist1poolnet 10 interfaceSerial0ipaddress171 69 232 182255 255 255 240ipnatoutside interfaceEthernet0ipaddress10 1 1 254255 255 255 0ipnatinside access list1permit10 1 1 00 0 0 255 Router shipnattransProInsideglobalInsidelocalOutsidelocalOutsideglobaltcp192 168 2 1 1100310 1 1 1 11003172 16 2 2 23172 16 2 2 23tcp192 168 2 1 106710 1 1 1 1067172 16 2 3 23172 16 2 3 23 VerifyingNAT AtranslationforaTelnetisstillactive TwodifferentinsidehostsappearontheoutsidewithasingleIPaddress BasicIPaddresstranslation UniqueTCPportnumbersareusedtodistinguishbetweenhosts Router showipnattransProInsideglobalInsidelocalOutsidelocalOutsideglobal 192 2 2 110 1 1 1 192 2 2 210 1 1 2 IPaddresstranslationwithoverloading Router debugipnatNAT s 10 1 1 1 192 168 2 1 d 172 16 2 2 0 NAT s 172 16 2 2 d 192 168 2 1 10 1 1 1 0 NAT s 10 1 1 1 192 168 2 1 d 172 16 2 2 1 NAT s 10 1 1 1 192 168 2 1 d 172 16 2 2 2 NAT s 10 1 1 1 192 168 2 1 d 172 16 2 2 3 NAT s 172 16 2 2 d 192 168 2 1 10 1 1 1 1 NAT s 172 16 2 2 d 192 168 2 1 10 1 1 1 1 NAT s 10 1 1 1 192 168 2 1 d 172 16 2 2 4 NAT s 10 1 1 1 192 168 2 1 d 172 16 2 2 5 NAT s 10 1 1 1 192 168 2 1 d 172 16 2 2 6 NAT s 172 16 2 2 d 192 168 2 1 10 1 1 1 2 TroubleshootingNAT Anexampleaddresstranslationinside to outside Areplytothepacketsent AnexampleTCPconversation inside to outside Indicatestranslationwasinthefastpath ClearingNATTranslationEntries Allentriesarecleared 192 168 2 2iscleared Router shipnattransProInsideglobalInsidelocalOutsidelocalOutsideglobaltcp192 168 2 1 1100310 1 1 1 11003172 16 2 2 23172 16 2 2 23tcp192 168 2 1 106710 1 1 1 1067172 16 2 3 23172 16 2 3 23router clearipnattrans router router showipnattrans router showipnattransProInsideglobalInsidelocalOutsidelocalOutsideglobaludp192 168 2 2 122010 1 1 2 1120171 69 2 132 53171 69 2 132 53tcp192 168 2 1 1100310 1 1 1 11003172 16 2 2 23172 16 2 2 23tcp192 168 2 1 106710 1 1 1 1067172 16 2 3 23172 16 2 3 23router clearipnattransudpinside192 168 2