第四章点到点协议(PPP)

第四章点到点协议（PPP）本章主题点到点协议链路控制协议配置选项配置PPP4.1PPP配置基础PPP是一种可以用于异步（拨号）或同步串行（ISDN）介质的数据链路层协议，它使用LCP建立并维护数据链路连接。4.1.1本节所讨论的命令EncapsulationpppUsernamenamepasswordPppauthenticationchap|papShowinterface4.1.2实验七配置PPP链路4.1.2.1所需设备1）2500系列路由器两台；2）运行终端仿真程序的PC一台；3）一条CISCO扁平线缆；4.1.2.2拓扑结构R4Lo04.4.4.4/323.0/24S1S0R3Lo03.3.3.3/324.1.2.3配置需求1）要求在不使用用户认证的情况下使得R4，R3的回环接口能够互相通信；2）使用PAP认证方式进行链路认证；3）删除PAP认证方式，改用CHAP认证方式进行认证；4.1.2.4配置步骤：第一步在CISCO路由器上配置PPP1）进入接口配置模式，封装二层协议PPP,配置IP地址；R4#shrunints1Buildingconfiguration...Currentconfiguration:81bytes!interfaceSerial1ipaddress172.16.3.4255.255.255.0encapsulationpppendR3#shrunints0Buildingconfiguration...Currentconfiguration:!interfaceSerial0ipaddress172.16.3.3255.255.255.0noipdirected-broadcastencapsulationpppclockrate64000end2）查看接口的封装情况；R3#shints0Serial0isup,lineprotocolisupHardwareisHD64570Internetaddressis172.16.3.3/24MTU1500bytes,BW1544Kbit,DLY20000usec,reliability255/255,txload1/255,rxload1/255EncapsulationPPP,loopbacknotsetKeepaliveset(10sec)LCPOpenOpen:IPCP,CDPCPLastinput00:00:09,output00:00:09,outputhangneverLastclearingofshowinterfacecounters00:05:59Inputqueue:0/75/0(size/max/drops);Totaloutputdrops:0Queueingstrategy:weightedfairOutputqueue:0/1000/64/0(size/maxtotal/threshold/drops)Conversations0/1/256(active/maxactive/maxtotal)ReservedConversations0/0(allocated/maxallocated)5minuteinputrate0bits/sec,0packets/sec5minuteoutputrate0bits/sec,0packets/sec60packetsinput,4246bytes,0nobufferReceived0broadcasts,0runts,0giants,0throttles0inputerrors,0CRC,0frame,0overrun,0ignored,0abort83packetsoutput,4238bytes,0underruns160outputerrors,0collisions,10interfaceresets0outputbufferfailures,0outputbuffersswappedout18carriertransitionsDCD=upDSR=upDTR=upRTS=upCTS=up3）使用debugppppackets打开调试程序；R3#00:47:17:Se0PPP:Ipkttype0xC021,datagramsize1600:47:17:Se0LCP:IECHOREQ[Open]id21len12magic0x10A273CA00:47:17:Se0LCP:OECHOREP[Open]id21len12magic0x00338DBA第二步配置可选的PPP认证——使用PAP协议1）在全局配置模式下配置用户名和密码注意：用户名是远程路由器的主机名，双方路由器的口令必须相同R4(config)#usernameR3passwordciscoR4(config)#R3(config)#usernameR4passwordciscoR3(config)#2）进入接口配置模式，选择PAP认证方式R3#shrunBuildingconfiguration...Currentconfiguration:!version12.0servicetimestampsdebuguptimeservicetimestampsloguptimenoservicepassword-encryption!hostnameR3!enablepasswordcisco!usernameR4password0cisco!!interfaceSerial0ipaddress172.16.3.3255.255.255.0noipdirected-broadcastencapsulationpppclockrate64000pppauthenticationpapppppapsent-usernameR3password702050D480809!R4#shrunBuildingconfiguration...Currentconfiguration:835bytes!version12.1noservicesingle-slot-reload-enableservicetimestampsdebuguptimeservicetimestampsloguptimenoservicepassword-encryption!hostnameR4!loggingrate-limitconsole10excepterrorsenablepasswordcisco!usernameR3password0ciscoipsubnet-zeronoipfingernoipdomain-lookup!cnsevent-serviceserver!!interfaceSerial1ipaddress172.16.3.4255.255.255.0encapsulationppppppauthenticationpapppppapsent-usernameR4password70822455D0A16!4）在R4打开DEBUGPPPAUTHENTICATION命令,先关闭接口，在打开接口；R4(config)#00:59:31:Se1PPP:Treatingconnectionasadedicatedline00:59:31:Se1PAP:OAUTH-REQid2len13fromR400:59:31:Se1PAP:IAUTH-REQid2len13fromR300:59:31:Se1PAP:IAUTH-ACKid2len500:59:31:Se1PAP:AuthenticatingpeerR300:59:31:Se1PAP:OAUTH-ACKid2len5R4(config)#第三步配置两种可选的PPP认证——首选CHAP，然后PAP1）在全局配置模式下配置用户名和密码注意：用户名是远程路由器的主机名，双方路由器的口令必须相同2）进入接口配置模式，选择CHAP和PAP认证方式R4#shrunints1Buildingconfiguration...Currentconfiguration:160bytes!interfaceSerial1ipaddress172.16.3.4255.255.255.0encapsulationppppppauthenticationchappapppppapsent-usernameR4password713061E010803endR3#shrunints0Buildingconfiguration...Currentconfiguration:!interfaceSerial0ipaddress172.16.3.3255.255.255.0noipdirected-broadcastencapsulationpppclockrate64000pppauthenticationchappapppppapsent-usernameR3password71511021F0725end3）打开DEBUGPPPAUTHENTICATION命令R4(config)#01:07:59:Se1PPP:Treatingconnectionasadedicatedline01:07:59:Se1CHAP:OCHALLENGEid2len23fromR401:07:59:Se1CHAP:ICHALLENGEid3len23fromR301:08:00:Se1CHAP:ORESPONSEid3len23fromR401:08:00:Se1CHAP:IRESPONSEid2len23fromR301:08:00:Se1CHAP:OSUCCESSid2len401:08:00:Se1CHAP:ISUCCESSid3len4R4(config)#