计算机网络实验报告一.docx
《计算机网络实验报告一.docx》由会员分享，可在线阅读，更多相关《计算机网络实验报告一.docx（22页珍藏版）》请在冰豆网上搜索。
计算机网络实验报告一
计算机网络实验报告一
班级：
智能1401
*******
学号：
************
一、HTTP
1.TheBasicHTTPGET/responseinteraction
实验步骤：
1.Startupyourwebbrowser.
2.StartuptheEtherealpacketsniffer,asdescribedintheIntroductorylab（butdon’t
yetbeginpacketcapture）.Enter“http”（justtheletters,notthequotationmarks）
inthedisplay-filter-specificationwindow,sothatonlycapturedHTTPmessages
willbedisplayedlaterinthepacket-listingwindow.（We’reonlyinterestedinthe
HTTPprotocolhere,anddon’twanttoseetheclutterofallcapturedpackets）.
3.Waitabitmorethanoneminute（we’llseewhyshortly）,andthenbeginEthereal
packetcapture.
4.Enterthefollowingtoyourbrowser
http:
//gaia.cs.umass.edu/ethereal-labs/HTTP-ethereal-file1.html
Yourbrowsershoulddisplaytheverysimple,one-lineHTMLfile.
5.StopEtherealpacketcapture.
实验结果：
1.IsyourbrowserrunningHTTPversion1.0or1.1?
WhatversionofHTTPisthe
serverrunning?
结果：
我的浏览器HTTP的版本是1.1，服务器的HTTP版本是1.1
2.Whatlanguages（ifany）doesyourbrowserindicatethatitcanaccepttothe
server?
结果：
浏览器可以接受的语言版本：
zh-Hans-CN,zh-Hans;q=0.8,en-US;q=0.5,en;q=0.3
3.WhatistheIPaddressofyourcomputer?
Ofthegaia.cs.umass.eduserver?
结果：
电脑的IP地址为192.168.1.8服务器IP为:
128.119.245.12
4.Whatisthestatuscodereturnedfromtheservertoyourbrowser?
结果：
状态代码是200（请求成功）
5.WhenwastheHTMLfilethatyouareretrievinglastmodifiedattheserver?
结果：
Last-Modified:
Tue,18Apr201705:
59:
01GMT\r\n
6.Howmanybytesofcontentarebeingreturnedtoyourbrowser?
结果：
返回到浏览器的内容的字节126
7.Byinspectingtherawdatainthepacketcontentwindow,doyouseeanyheaders
withinthedatathatarenotdisplayedinthepacket-listingwindow?
Ifso,name
one通过检查数据包内容窗口中的原始数据，您会看到任何标题在数据包列表窗口中未显示的数据中？
如果是这样，找出一个。
结果：
没有。
2.TheHTTPCONDITIONALGET/responseinteraction
实验步骤：
•Startupyourwebbrowser,andmakesureyourbrowser’scacheiscleared,as
discussedabove.
•StartuptheEtherealpacketsniffer
•EnterthefollowingURLintoyourbrowser
http:
//gaia.cs.umass.edu/ethereal-labs/HTTP-ethereal-file2.html
Yourbrowsershoulddisplayaverysimplefive-lineHTMLfile.
•QuicklyenterthesameURLintoyourbrowseragain（orsimplyselecttherefresh
buttononyourbrowser）
•StopEtherealpacketcapture,andenter“http”inthedisplay-filter-specification
window,sothatonlycapturedHTTPmessageswillbedisplayedlaterinthe
packet-listingwindow.
•（Note:
IfyouareunabletorunEtherealonalivenetworkconnection,youcan
usethehttp-ethereal-trace-2packettracetoanswerthequestionsbelow;see
footnote1.Thistracefilewasgatheredwhileperformingthestepsaboveonone
oftheauthor’scomputers.）
实验结果：
8.InspectthecontentsofthefirstHTTPGETrequestfromyourbrowsertothe
server.Doyouseean“IF-MODIFIED-SINCE”lineintheHTTPGET?
结果：
第一次HTTPGET没有看到“IF-MODIFIED-SINCE”
9.Inspectthecontentsoftheserverresponse.Didtheserverexplicitlyreturnthe
contentsofthefile?
Howcanyoutell?
检查服务器响应的内容。
服务器是否显式返回文件的内容？
你怎么知道？
结果：
返回内容：
10.NowinspectthecontentsofthesecondHTTPGETrequestfromyourbrowserto
theserver.Doyouseean“IF-MODIFIED-SINCE:
”lineintheHTTPGET?
If
so,whatinformationfollowsthe“IF-MODIFIED-SINCE:
”header?
客户端第二次请求此URL时，根据HTTP协议的规定，浏览器会向服务器传送If-Modified-Since报头
结果：
有“IF-MODIFIED-SINCE:
”，内容是：
If-Modified-Since:
Sat,22Apr201705:
59:
01GMT\r\n
11.WhatistheHTTPstatuscodeandphrasereturnedfromtheserverinresponseto
thissecondHTTPGET?
Didtheserverexplicitlyreturnthecontentsofthefile?
Explain.
答案：
状态码和相应状态信息的值为302MovedTemporarily。
代表的意思是新的URL应该被视为临时性的替代。
3.RetrievingLongDocuments
实验步骤：
•Startupyourwebbrowser,andmakesureyourbrowser’scacheiscleared,as
discussedabove.
•StartuptheEtherealpacketsniffer
•EnterthefollowingURLintoyourbrowser
http:
//gaia.cs.umass.edu/ethereal-labs/HTTP-ethereal-file3.html
YourbrowsershoulddisplaytheratherlengthyUSBillofRights.
•StopEtherealpacketcapture,andenter“http”inthedisplay-filter-specification
window,sothatonlycapturedHTTPmessageswillbedisplayed.
•（Note:
IfyouareunabletorunEtherealonalivenetworkconnection,youcan
usethehttp-ethereal-trace-3packettracetoanswerthequestionsbelow;see
footnote1.Thistracefilewasgatheredwhileperformingthestepsaboveonone
oftheauthor’scomputers.）
实验结果：
12.HowmanyHTTPGETrequestmessagesweresentbyyourbrowser?
结果：
2个GET请求
13.Howmanydata-containingTCPsegmentswereneededtocarrythesingleHTTP
response?
需要多少数据包含TCP片段来承载单个HTTP响应？
结果：
4个
14.WhatisthestatuscodeandphraseassociatedwiththeresponsetotheHTTPGET
request?
答案：
状态码和短语是200OK：
表示请求成功，信息包含在响应的报文中。
15.ArethereanyHTTPstatuslinesinthetransmitteddataassociatedwithaTCPinduced“Continuation”?
结果：
有，对于一个大的HTML文件会被TCP分为若干个独立的包。
4.HTMLDocumentswithEmbeddedObjects
实验步骤：
•Startupyourwebbrowser,andmakesureyourbrowser’scacheiscleared,as
discussedabove.
•StartuptheEtherealpacketsniffer
•EnterthefollowingURLintoyourbrowser
http:
//gaia.cs.umass.edu/ethereal-labs/HTTP-ethereal-file4.html
YourbrowsershoulddisplayashortHTMLfilewithtwoimages.Thesetwo
imagesarereferencedinthebaseHTMLfile.Thatis,theimagesthemselvesare
notcontainedintheHTML;insteadtheURLsfortheimagesarecontainedinthe
downloadedHTMLfile.Asdiscussedinthetextbook,yourbrowserwillhaveto
retrievetheselogosfromtheindicatedwebsites.Ourpublisher’slogois
retrievedfromthewebsite.Theimageofourbook’scoveris
storedatthemanic.cs.umass.eduserver.
•StopEtherealpacketcapture,andenter“http”inthedisplay-filter-specification
window,sothatonlycapturedHTTPmessageswillbedisplayed.
•（Note:
IfyouareunabletorunEtherealonalivenetworkconnection,youcan
usethehttp-ethereal-trace-4packettracetoanswerthequestionsbelow;see
footnote1.Thistracefilewasgatheredwhileperformingthestepsaboveonone
oftheauthor’scomputers.）
实验结果：
16.HowmanyHTTPGETrequestmessagesweresentbyyourbrowser?
Towhich
InternetaddressesweretheseGETrequestssent?
结果：
浏览器一共发出了4个HTTPGET请求，目的IP如图所示
17.Canyoutellwhetheryourbrowserdownloadedthetwoimagesserially,or
whethertheyweredownloadedfromthetwowebsitesinparallel?
Explain.
浏览器在下载这两个图片时，是串行下载还是并行下载？
请解释
结果：
是并⾏下载。
因为两个图⽚片是连续请求,并没有等第⼀个图片请求得到回复后才继续第二次请求。
5.HTTPAuthentication
实验步骤：
•Makesureyourbrowser’scacheiscleared,asdiscussedabove,andclosedown
yourbrowser.Then,startupyourbrowser
•StartuptheEtherealpacketsniffer
•EnterthefollowingURLintoyourbrowser
http:
//gaia.cs.umass.edu/ethereal-labs/protected_pages/HTTP-ethereal-file5.html
Typetherequestedusernameandpasswordintothepopupbox..
•StopEtherealpacketcapture,andenter“http”inthedisplay-filter-specification
window,sothatonlycapturedHTTPmessageswillbedisplayedlaterinthe
packet-listingwindow.
•（Note:
IfyouareunabletorunEtherealonalivenetworkconnection,youcan
usethehttp-ethereal-trace-5packettracetoanswerthequestionsbelow;see
footnote1.Thistracefilewasgatheredwhileperformingthestepsaboveonone
oftheauthor’scomputers.）
实验结果：
18.Whatistheserver’sresponse（statuscodeandphrase）inresponsetotheinitial
HTTPGETmessagefromyourbrowser?
对于浏览器发出的最初的HTTP GET请求，服务器的响应是什么？
结果：
401Unauthorized（XX）
19.Whenyourbrowser’ssendstheHTTPGETmessageforthesecondtime,what
newfieldisincludedintheHTTPGETmessage?
当浏览器发出第二个HTTPGET请求时，在HTTPGET报文中包含了哪些新的字段？
结果：
出现新字段：
Authorization:
BasicMTEyMzoyMzEz\r\n
Credentials:
1123:
2313（用户名及密码）
第一次请求：
第二次请求：
二、TCP
实验步骤：
1.CapturingabulkTCPtransferfromyourcomputertoaremote
Server
2.Afirstlookatthecapturedtrace
3.TCPBasics
实验结果：
1.WhatistheIPaddressandTCPportnumberusedbyyourclientcomputer
（source）totransferthefiletogaia.cs.umass.edu?
WhatistheIPaddressandport
numberusedbygaia.cs.umass.edutoreceivethefile.
答：
client computer:
IP address:
10.63.236.170 TCP port number:
60813
Gaia.cs.umass.edu:
IP address:
128.119.245.12 TCP port number:
80
2.WhatisthesequencenumberoftheTCPSYNsegmentthatisusedtoinitiatethe
TCPconnectionbetweentheclientcomputerandgaia.cs.umass.edu?
Whatisit
inthesegmentthatidentifiesthesegmentasaSYNsegment?
答：
第一次握手：
Sequencenumber:
0（relativesequencenumber）,SYN被置位，SYN=1
第二次握手：
Sequencenumber:
0，Acknowledgmentnumber:
1，SYN=1
第三次握手：
Sequencenumber:
1，Acknowledgmentnumber:
1，SYN=0
3.WhatisthesequencenumberoftheSYNACKsegmentsentbygaia.cs.umass.edu
totheclientcomputerinreplytotheSYN?
Whatisthevalueofthe
ACKnowledgementfieldintheSYNACKsegment?
Howdidgaia.cs.umass.edu
determinethatvalue?
Whatisitinthesegmentthatidentifiesthesegmentasa
SYNACKsegment?
答：
由上一个题目可知，三次握手的过程中，第二次握手[SYNACK]Sequencenumber:
0，Acknowledgmentnumber:
1，SYN=1；第三次握手[ACK]Sequencenumber:
1，Acknowledgmentnumber:
1，SYN=0，其中Acknowledgmentnumber=上一个Sequencenumbe+1。
实验结果和理论一致。
4.WhatisthesequencenumberoftheTCPsegmentcontainingtheHTTPPOST
command?
NotethatinordertofindthePOSTcommand,you’llneedtodiginto
thepacketcontentfieldatthebottomoftheEtherealwindow,lookingfora
segmentwitha“POST”withinitsDATAfield.
答：
TCPsegmentdata（481bytes）
5.ConsidertheTCPsegmentcontainingtheHTTPPOSTasthefirstsegmentinthe
TCPconnection.Whatarethesequencenumbersofthefirstsixsegmentsinthe
TCPconnection（includingthesegmentcontainingtheHTTPPOST）?
Atwhat
timewa
升级会员 