2024年HTTP 计算机网络实验报告

陕西師范大學计算机网络试验汇报试验三HTTP一、试验目的1.通過使用wireshark软件掌握基本的GET，HTTP/响应交互和消息格式2．掌握探索HTTP协议的措施。二、试验器材1.PC机電脑一台。2．下载wireshark软件并安装三、试验操作环节及成果1.TheBasicHTTPGET/responseinteraction1Startupyourwebbrowser.2.StartuptheWiresharkpacketsniffer,asdescribedintheIntroductorylab(butdon’tyetbeginpacketcapture).Enter“http”(justtheletters,notthequotationmarks)inthedisplay-filter-specificationwindow,sothatonlycapturedHTTPmessageswillbedisplayedlaterinthepacket-listingwindow.(We’reonlyinterestedintheHTTPprotocolhere,anddon’twanttoseetheclutterofallcapturedpackets).3.Waitabitmorethanoneminute(we’llseewhyshortly),andthenbeginWiresharkpacketcapture.4.EnterthefollowingtoyourbrowserYourbrowsershoulddisplaytheverysimple,one-lineHTMLfile.5.StopWiresharkpacketcapture.试验截图如下：1.IsyourbrowserrunningHTTPversion1.0or1.1?WhatversionofHTTPistheserverrunning?我的浏览器上运行的HTTP版本是1.1，在版本為的HTTP服务器上运行。2.Whatlanguages(ifany)doesyourbrowserindicatethatitcanaccepttotheserver?表明可以接受的語言是：3.WhatistheIPaddressofyourcomputer?Oftheserver?我的计算机的IP地址是：2，服务器是：2。4.Whatisthestatuscodereturnedfromtheservertoyourbrowser?

5.WhenwastheHTMLfilethatyouareretrievinglastmodifiedattheserver?

6.Howmanybytesofcontentarebeingreturnedtoyourbrowser?

7.Byinspectingtherawdatainthepacketcontentwindow,doyouseeanyheaderswithinthedatathatarenotdisplayedinthepacket-listingwindow?Ifso,nameone如下网页可得：Congratulations.You'vedownloadedthefile!2.TheHTTPCONDITIONALGET/responseinteraction•StartuptheWiresharkpacketsniffer•EnterthefollowingURLintoyourbrowserYourbrowsershoulddisplayaverysimplefive-lineHTMLfile.•QuicklyenterthesameURLintoyourbrowseragain(orsimplyselecttherefreshbuttononyourbrowser)•StopWiresharkpacketcapture,andenter“http”inthedisplay-filter-specificationwindow,sothatonlycapturedHTTPmessageswillbedisplayedlaterinthepacket-listingwindow.•(Note:IfyouareunabletorunWiresharkonalivenetworkconnection,youcanusethehttp-ethereal-trace-2packettracetoanswerthequestionsbelow;seefootnote1.Thistracefilewasgatheredwhileperformingthestepsaboveononeoftheauthor’scomputers.)试验截图如下：

8.InspectthecontentsofthefirstHTTPGETrequestfromyourbrowsertotheserver.Doyouseean“IF-MODIFIED-SINCE”lineintheHTTPGET?没有看到。9.Inspectthecontentsoftheserverresponse.Didtheserverexplicitlyreturnthecontentsofthefile?Howcanyoutell?10.NowinspectthecontentsofthesecondHTTPGETrequestfromyourbrowsertotheserver.Doyouseean“IF-MODIFIED-SINCE:”lineintheHTTPGET?Ifso,whatinformationfollowsthe“IF-MODIFIED-SINCE:”header?有，11.WhatistheHTTPstatuscodeandphrasereturnedfromtheserverinresponsetothissecondHTTPGET?Didtheserverexplicitlyreturnthecontentsofthefile?Explain.304notmodifiedCache裏已經有不會再返回内容3.RetrievingLongDocumentsInourexamplesthusfar,thedocumentsretrievedhavebeensimpleandshortHTMLfiles.Let’snextseewhathappenswhenwedownloadalongHTMLfile.Dothefollowing:•Startupyourwebbrowser,andmakesureyourbrowser’scacheiscleared,asdiscussedabove.•StartuptheWiresharkpacketsniffer•EnterthefollowingURLintoyourbrowserYourbrowsershoulddisplaytheratherlengthyUSBillofRights.•StopWiresharkpacketcapture,andenter“http”inthedisplay-filter-specificationwindow,sothatonlycapturedHTTPmessageswillbedisplayed.•(Note:IfyouareunabletorunWiresharkonalivenetworkconnection,youcanusethehttp-ethereal-trace-3packettracetoanswerthequestionsbelow;seefootnote1.Thistracefilewasgatheredwhileperformingthestepsaboveononeoftheauthor’scomputers.)12.HowmanyHTTPGETrequestmessagesweresentbyyourbrowser?2個13.Howmanydata-containingTCPsegmentswereneededtocarrythesingleHTTPresponse?414.WhatisthestatuscodeandphraseassociatedwiththeresponsetotheHTTPGETrequest?200okFavicon.con15.ArethereanyHTTPstatuslinesinthetransmitteddataassociatedwithaTCP-induced“Continuation”?No，新版本整合了所有数据包内容16.HowmanyHTTPGETrequestmessagesweresentbyyourbrowser?TowhichInternetaddressesweretheseGETrequestssent?三個基本页:2图片17.Canyoutellwhetheryourbrowserdownloadedthetwoimagesserially,orwhethertheyweredownloadedfromthetwowebsitesinparallel?Explain.并行，两個页面是持续祈求，并没有等待第一种祈求得到答复才继续第二次祈求1