计算机网络实验报告4.docx

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1、福建格林大孽计耳机与彩包孽陵实验报告课程名称：计算机网络姓名：学院：计算机与信息学院专业：计算机科学与技术年级：学号：指导教师：职称：年月曰实验工程列表序号实验工程名称成绩指导教师1TCP协议分析2345678总评实验报告实验四TCP协议分析一、实验目的1、掌握TCP报文段首部各字段的含义；2、掌握TCP的建立连接的三次握制；3、了解TCP确实认机制；4、了解TCP的流量控制和拥塞控制。二、实验原理利用数据捕获技术来完成实验。TCP协议的根本概念，TCP确实认机制。三、实验步骤下载网络数据包捕获工具（SnifferWiresharkEtherea1、IriS等，安装，运行，进行数据捕获。找出T

2、CP数据包。进行如下操作：1分析某个TCP数据包各字段的值并解释；2找出建立连接时的TCP数据包进行分析；3找出TCP数据包，解释TCP确实认机制；4找出TCP数据包，解释TCP的流量控制和拥塞控制机制。以Wireshark为例，具体实验步骤如下：1 .组建对等网这个环节省略，因为实验室中都已经建好了。但要自己要决定哪一台作为效劳器，哪一台作为客户器，现在分别记为Server和Client0例如：Server的IP地址为192.168.2.92,Client的IP地址为192.168.2.93（就是本机）2 .在效劳器端安装FTP效劳器软件这里出于试验内容简单考虑，使用简单的FTP效劳器软件H

3、omeFtPSerVer。不需要安装，直接解压即可。HomeFtpServer设置如下：1）HomeFtpServer主界面2)HomeFtPSerVer简单配置匿名访问)WebInterfaceBannedListGeneralAnonymousLogDomain(匿名访问根目录的设置,后面是各访问权限选项0AllowanonymoususersAnonYmoUSHomeDirectory:DAtestBrowse0Allowdownloadfiles Allowuploadfiles Allowrenamingfiles(ordirs) Allowdeletingfiles0Allowch

4、angedirectoryAlloweatingdirectoriesAllowdeletingdirectoriesDirAlias:Cancel这些设置完成后，就可以启动HOmeFtPSerVer。具体步骤如下：1)HomeFtpServer主界面选择“FtpServer-Settings”，翻开设置界面如下:3选择Anonymous选项卡，设置如下：4点击APPIy应用5最后点击主界面StartSerVer开始效劳。3 .在客户端启动监听程序具体步骤为：在客户端翻开WireShark监听程序，在菜单栏上选择CaPtUre-OPtions,翻开设置窗口，在CaPtUreFilter中输入t

5、cpand192.168.2.93,点击右下角的Start开始监听。4 .在客户机上运行FTP程序，从效劳器上下载一个文件到客户机这里直接使用IE浏览器或资源管理器访问就可以了(ftp:/192.168.2.92，该IP地址是server的IP地址。具体步骤是：翻开资源管理器,输入地址为:ftp192.168.2.92Q转到口叵I区0三-HH转到画飞实验四TCP协议分析OlVireshark).docInternet用尸：匿名2翻开效劳器中的“实验四TCP.doc”文件，此时观察WireShark中已记录的数据。IarvellYukonEthernetController(Iicrosoft,

6、s:PacketScheduler)CtCPandhost192.16tI.2.93)-TireshFileEditViewGoCaptureAnalyzeStatisticsTelephonyToolsHelp飘翼翻翻事I臼日於0昌Iq伞吟5济I0QE3第国咽%I回Filter：_Expression.ClearApplyNo.TimeSourceDestinationProtocolZBI10.000000192.168.2.93192.168.2.92FTPRequest:TYPEI20.000568192.168.2.92192.168.2.93FTPResponse:200Types

7、ettoI.30.000715192.168.2.93192.168.2.92FTPRequest:PASV40.001770192.168.2.92192.168.2.93FTPResponse:227EnteringPassiv50.001853192.168.2.93192.168.2.92TCPtd-postmanatroqLSYNJSeq=60.002564192.168.2.92192.168.2.93TCPafrogtd-postmanSYN,ack70.002576192.168.2.93192.168.2.92TCPtd-postmanafrogackSeq=80.00280

8、1192.168.2.93192.168.2.92FTPRequest:SIZEA312265321390.003577192.168.2.92192.168.2.93FTPResponse:213571904100.003701192.168.2.93192.168.2.92FTPRequest:RETR3122653213110.004571192.168.2.92192.168.2.93FTPResponse:150Openingdataco120.004766192.168.2.92192.168.2.93FTP-DATAftpData:1460bytes130.004775192.1

9、68.2.92192.168.2.93FTP-DATAftpData:1460bytes140.004785192.168.2.93192.168.2.92TCPtd-postmanafrogACKSeq=150.005574192.168.2.92192.168.2.93FTP-DATAFTPData:1460bytes160.005585192.168.2.92192.168.2.93FTP-DATAFTPData:1460bytes170.005594192.168.2.93192.168.2.92TCPtd-postmanafrogackSeq=180.005605192.168.2.

10、92192.168.2.93FTP-DATAFTPData:1460bytes1Q1Q7IEa?Q71Q71fiR-Q2CTP-T匚TPC=T=14fihTu田Frame1:62bytesonwire(496bits),62bytescaptured(496bits)田EthernetII,Src:HonHaiPr_a2:al:f2(44:37:e6:a2:al:f2),Dst:HonHaiPr_a2:a3:9f(44:37:e6:a2:a3:9f)SllnternetProtocol,Src:192.168.2.93(192.168.2.93),Dst:192.168.2.92(192.16

11、8.2.92)()TransmissioncontrolProtocol,SrcPort:fpitp(1045),DstPort:ftp(21),Seq:1,Ack:1,Len:8田FileransferProtocol(FTP)OOOOOOlO00200030440002fa37e6a23011e55c0415a862ca39f4437400040060015622900005459e6a2alf2a2d9ca8al5a8eOd50452049080221Od0045005dca8eO5018OaD7.D7E.0.b)Z.!.P.9.TYPEI5 .分析该TCP数据包各字段的值1分析该TCP

12、数据包各字段的值从上图可以看出，源端口号为1049,目的端口号为1042,序列号为1,确认号为0,头文件长度为32字节，标记为0x02(SYN),窗口大小为65535,检验和为OXdb61等信息。Baa.pcap-WiresharkJFileEditViewGoCaptureAnalyzeStatisticsTelephonyToolsHelpBl稼才赢僦I白届将e昌Iqq嗓存*bTbqq0edi第国网舞iFilter:Expression.ClearApplyNo.TimeSourceDestinationProtocolInfo10.000000192.168.2.93192.168.2.

13、92FTPRequest:typeI20.000568192.168.2.92192.168.2.93FTPResponse:200TypesettoI.30.000715192.168.2.93192.168.2.92FTPRequest:PASV40.001770192.168.2.92192.168.2.93FTPResponse:227EnteringPassiveMode(192,：50.001853192.168.2.93192.168.2.92TCPtd-postmanafrogSYNSeq=OWin=65535i0.002564192.168.2.92192.168.2.93T

14、CPafrogtd-postmanSYN,ackSeq=OAck=I70.002576192.168.2.93192.168.2.92TCPtd-postmanafrogackSeq=IAck=Iwin=；80.002801192.168.2.93192.168.2.92FTPRequest:SIZE3122653213513133O4-90.003577192.168.2.92192.168.2.93FTPResponse:213571904100.003701192.168.2.93192.168.2.92FTPRequest:RETR3122653213513133O4110.00457

15、1192.168.2.92192.168.2.93FTPResponse:150openingdataconnectionfor12 0.004766192.168.2.92192.168.2.93FTP-DATFTPData:1460bytes13 0.004775192.168.2.92192.168.2.93FTP-DATFTPData:1460bytes14 0.004785192.168.2.93192.168.2.92TCPtd-postmanafrogACKSeq=IAck=2921W15 0.005574192.168.2.92192.168.2.93FTP-DATFTPDat

16、a：1460bytes16 0.005585192.168.2.92192.168.2.93FTP-DATFTPData:1460bytes17 0.005594192.168.2.93192.168.2.92TCPtd-postmanafrogACKSeq=IAck=5841W18 0.005605192.168.2.92192.168.2.93FTP-DATFTPData:1460bytes19 0.006368192.168.2.92192.168.2.93FTP-DATFTPData:1460bytes20 0.006375192.168.2.93192.168.2.92TCPtd-p

17、ostmanafrogACKSeq=IAck=8761W21 0.006383192.168.2.92192.168.2.93FTP-DAlFTPData:1460bvtes(I田Frame5:66bytesonwire(528bits),66bytescaptured(528bits)田EthernetII,Src:HonHaiPr_a2:al:f2(44:37:e6:a2:al:f2),Dst:HonHaiPr_a2:a3:9f(44:37:e6:a2:a3:9f)EllnternetProtocol,Src:192,168.2.93(192.168.2.93),Dst:192,168.2

18、92(192.168.2.92)sourceport:td-postman(1049)Desfinationport:afrog(1042)streamindex:1Sequencenumber:0(relativesequencenumber)Headerlength:32bytes田Flags:0x02(SYN)Windowsize:65535田Checksum:0xdb61validationdisabled田OPtions:(12bytes)2）找出建立连接时的tcp数据包进行分析。可以发现第5段数中seq=O,即为建立连接时的TCP数据包。40.001770192.168.2.92

19、192.168.2.93FTPResponse:227EnteringPassiveMode(192,168,2,92,4,18).I50.001853192.168.2.93192.168.2.92TCPtd-postmanafrogSYNSeq=OWin=65535Len=OMSS=1460WS=2SACK_PERM=160.002564192.168.2.92192.168.2.93TCPafrogtd-postmanSYN,ACKSeq=OAck=IWin=65535Len=OMSS=1460WS=2:70.002576192.168.2.93192.168.2.92TCPtd-pos

20、tmanafrogackseq=lAck=Iwin=256960Len=O80.002801192.168.2.93192.168.2.92FTPRequest：SIZEA3122653213513133O4TCP3202553223512673263163）找出TCP数据包，解释TCP确实认机制第15、16两段数据中ACK=1,为确认信号。可以发现第14、15、16三段值即为TCP连接的三次握手。第14段：140.004785192.168.2.93192.168.2.92TCP150.005574192.168.2.92192.168.2.93FTP-D/16O.5585192.168.2

21、92192.168.2.93FTP-DX17O,005594192.168.2.93192.168.2.92TCP日Frame14:54bytesonwire(432bits),54bytescaptured(4OEthernetII,Src:HonHaiPr_a2:al:f2(44:37:e6:a2:al:f2),DstBinternetProtocol,Src:192.168.2.93(192.168.2.93),Dst:IsElTransmissioncontrolProtocol,SrcPort:td-postman(1049),Sourceport:td-postman(1049)

22、Destinationport:afrog(1042)streamindex:1sequencenumber:1(relativesequencenumber)Acknowledgementnumber:2921(relativeacknumber)Headerlength:20bytes田Flags:OxlO(ACK)windowsize:256960(scaled)(Schecksum:0x8624validationdisabledseq/ackanalysis第15段:Frame15:1514bytesonwire(12112bits),1514bytescapturedCEthern

23、erII,Src:HonHaiPr_a2:a3:9f(44:37:e6:a2:a3:9f),Dsr:HoiInternetProtocol,Src:192.168.2.92(192.168.2.92),Dst:192.16.TransmissoncontrolProtocol,SrcPort:afrog(1042),DstPort:Sourceport:afrog(1042)Destinationport:td-postman(1049)streamndex:1sequencenumber:2921(relativesequencenumber)Nextsequencenumber:4381(

24、relativesequencenumber)Acknowledgementnumber:1(relativeacknumber)Header1ength:20bytes国Flags:OxlO(ack)windowsize:256960(sealed)()checksum:04Of2val1dationdisabled(Sseq/ackanalysis第16段:160.005585192.168.2.92192.168.2.93FTP-DAlFTPD170.005594192.168.2.93192.168.2.92TCPtd-poiFrame16:1514bytesonwire(12112b

25、its),1514bytescaptured(121EthernetII,Src:HonHaiPr_a2:a3:9f(44:37:e6:a2:a3:9f),Dst:HonHiinternetProtocol,Src:192.168.2.92(192.168.2.92),Dst:192.168.；TransmissioncontrolProtocol,SrcPort:afrog(1042),DstPort:tcsourceport:afrog(1042)Destinationport:td-postman(1049)streamindex:1sequencenumber:4381(relativesequencenumber)Nextsequencenumber:5841(relativesequencenumber)Acknowledgementnumber:1(relativeacknumber)Headerlength:20bytes()Flags:OxlO(ACK)Windowsize:256960(scaled)Schecksum:0x6302validationdisabled()seq/ackanalysis(4找出TCP数据包，解释TCP的流量控制和拥塞控制机制四、总结通过本次实验了解TCP报文首部格式，认识TCP协议的工作原理和运行机制。