DHCP实验报告

DHCP实验报告姓名：朱敏学号：41412056班级：计科2班1.AreDHCPmessagessentoverUDPorTCP?由图可知：UDP2.Drawatimingdatagramillustratingthesequenceofthefirstfour-packetDiscover/Offer/Request/ACKDHCPexchangebetweentheclientandserver.Foreachpacket,indicatedthesourceanddestinationportnumbers.Aretheportnumbersthesameasintheexamplegiveninthislabassignment?3.Whatisthelink-layer(e.g.,Ethernet)addressofyourhost?由图可知：00:06:25:da:af:734.WhatvaluesintheDHCPdiscovermessagedifferentiatethismessagefromtheDHCPrequestmessage?5.WhatisthevalueoftheTransaction-IDineachofthefirstfour(Discover/Offer/Request/ACK)DHCPmessages?WhatarethevaluesoftheTransaction-IDinthesecondset(Request/ACK)setofDHCPmessages?WhatisthepurposeoftheTransaction-IDfield?由图可知：第一组地址为0x3e5e0ce3第二组地址为0x257e55a36.AhostusesDHCPtoobtainanIPaddress,amongotherthings.Butahost’sIPaddressisnotconfirmeduntiltheendofthefour-messageexchange!IftheIPaddressisnotsetuntiltheendofthefour-messageexchange,thenwhatvaluesareusedintheIPdatagramsinthefour-messageexchange?ForeachofthefourDHCPmessages(Discover/Offer/Request/ACKDHCP),indicatethesourceanddestinationIPaddressesthatarecarriedintheencapsulatingIPdatagram.由图可知：都用了255.255.255.255这个目的地址，当服务器运行时，client资源地址为0.0.0.0.7.WhatistheIPaddressofyourDHCPserver?8.WhatIPaddressistheDHCPserverofferingtoyourhostintheDHCPOffermessage?IndicatewhichDHCPmessagecontainstheofferedDHCPaddress.由图可知：提供的IP地址为192.168.1.1019.Intheexamplescreenshotinthisassignment,thereisnorelayagentbetweenthehostandtheDHCPserver.Whatvaluesinthetraceindicatetheabsenceofarelayagent?Istherearelayagentinyourexperiment?IfsowhatistheIPaddressoftheagent?由图可知：中介代理IP地址为0.0.0.0没有。10.ExplainthepurposeoftherouterandsubnetmasklinesintheDHCPoffermessage.供DHCP用户在最后收到ACK后启动IP配置时设置掩码和开关11.IntheDHCPtracefilenotedinfootnote2,theDHCPserveroffersaspecificIPaddresstotheclient(seealsoquestion8.above).Intheclient’sresponsetothefirstserverOFFERmessage,doestheclientacceptthisIPaddress?Whereintheclient’sRESPONSEistheclient’srequestedaddress?12.Explainthepurposeoftheleasetime.Howlongistheleasetimeinyourexperiment?由图可知：租用期是DHCP得到IP的有效使用期，当使用期过后，DHCP服务器收回该IP地址，有利于IP地址的充分利用。租用时间从ACK包中获得，租聘时间1天13.WhatisthepurposeoftheDHCPreleasemessage?DoestheDHCPserverissueanacknowledgmentofreceiptoftheclient’sDHCPrequest?Whatwouldhappeniftheclient’sDHCPreleasemessageislost?DHCPrelease消息的作用是释放租用的IP地址；没有收到；服务器在时间过后停用IP地址。14.ClearthebootpfilterfromyourWiresharkwindow.WereanyARPpacketssentorreceivedduringtheDHCPpacket-exchangeperiod?Ifso,explainthepurposeofthoseARPpackets.有通过广播插叙IP地址。