Use a wireshark to solve this problem please The HTTP CONDITIONAL GET/response i

Question

Use a wireshark to solve this problem please

The HTTP CONDITIONAL GET/response interaction

Before performing the
steps below, make sure your browser’s cache is empty. (To do this under Firefox, select
Tools->Clear Recent History and check the Cache box, or for Internet Explorer, select
Tools->Internet Options->Delete File; these actions will remove cached files from your
browser’s cache.) Now do the following:
• Start up your web browser, and make sure your browser’s cache is cleared, as
discussed above.
• Start up the Wireshark packet sniffer
• Enter the following URL into your browser
http://gaia.cs.umass.edu/wireshark-labs/HTTP-wireshark-file2.html
Your browser should display a very simple five-line HTML file.
• Quickly enter the same URL into your browser again (or simply select the refresh
button on your browser)
• Stop Wireshark packet capture, and enter “http” in the display-filter-specification
window, so that only captured HTTP messages will be displayed later in the
packet-listing window.
• (Note: If you are unable to run Wireshark on a live network connection, you can
use the http-ethereal-trace-2 packet trace to answer the questions below; see
footnote 1. This trace file was gathered while performing the steps above on one
of the author’s computers.)
Answer the following questions:
1. Inspect the contents of the first HTTP GET request from your browser to the
server. Do you see an “IF-MODIFIED-SINCE” line in the HTTP GET?
2. Inspect the contents of the server response. Did the server explicitly return the
contents of the file? How can you tell?
3. Now inspect the contents of the second HTTP GET request from your browser to
the server. Do you see an “IF-MODIFIED-SINCE:” line in the HTTP GET? If
so, what information follows the “IF-MODIFIED-SINCE:” header?
4. What is the HTTP status code and phrase returned from the server in response to
this second HTTP GET? Did the server explicitly return the contents of the file?
Explain.

Explanation / Answer

1) No I don't see an "IF-MODIFIED-SINCE" line in HTTP GET

2) Yes the server explicitly returned the contents of the file.It can be figured out using response code HTTP/1.1 200 OK and response length Content-Length: 371

3) Yes I can see a "IF-MODIFIED-SINCE" line in HTTP GET.It has the the following data If-Modified-Since: Tue, 11 Sep 2018 05:59:01 GMT which is same as
Last-Modified: Tue, 11 Sep 2018 05:59:01 GMT from the response of the first request

4) The HTTP status code and phrase returned are HTTP/1.1 304 Not Modified.The server did not return the contents instead responded that the contents of the file is not changed using 304 response code

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