5) Consider the HTTP protocol. HTTP is the protocol the protocol used for sending the contents of web pages between hosts, from a web server to an agent (client like firefox or explorer). HTTP is also used by agents to make requests to web servers for particular web pages. HTTP communications, both requests and replies travel through TCP connections. The packets sent back and forth between an agent requesting web pages and the web server receiving the web page were captured using the packet sniffer wireshark. All the provided files provide a list of packets that were transmitted when two web pages were requested using the chrome browser on a windows 10 machine.

Summary data was captured and is provided for you in the files testHTTP.pdf and converasationonly.pdf. The file testHTTP.pdf contains a list of packet headers for all HTTP packets generated as the two web pages were displayed. The conversationonly.pdf file contains a list of packet headers for one of the several TCP conversations that were generated by requesting the first web page, it includes the related HTTP requests and replies (also in testHTTP.pdf) and the TCP data transfers for the requested objects..

Detailed contents of a small number of the packets are provided in the files detailsTestHTTP.pdf and detailsRetest.pdf. The file detailsTestHTTP.pdf contains the packet details when the first request is made for the first web page when there is no information about the webpage in the cache. The file detailRetest.pdf contains the details for the same request when there is information about the webpage in the cache.

All packets listed in the summary data files are included in the testhttp.pcapng Wireshark file. If you open this file with Wireshark you can see the contents of all these packets. This file should not be needed but provides information that may help you more completely understand the provided files.

Based on the information in these files answer each of the following questions. In each case explain how the contents of the files supports the answer you have given.

a) What is the difference between a basic HTTP GET request and a conditional

HTTP get request? When is each type of request used?

b) What is different about the responses to a basic HTTP GET command and to a

conditional HTTP GET request? What information does each type of response return? Would you expect a different response to the conditional get if the web page had been modified between the two requests?

c) What browser is making the request? What version of HTTP is that browser running? What version of HTTP is the queried web server running?

d) What was the IP address of the computer running the browser? What was the IP address of the web server it queried? Use evidence from the file testHTTP.pdf.

e) For one of the HTTP GET responses shown in file conversationonly.pdf how many packets were used to carry the HTTP GET response from the server to the client?

Now consider the file testHTTP.pdf and the file conversationonly.pdf. These files contains a query made for a web page including multiple objects. Based on the contents of these files answer the following questions: f) Were persistent or non-persistent connections used to download the webpage

information from the server? Why? g) Was pipelining used to download the webpage information from the server?