HTTP Protocol Analysis and Testing: A Practical Telnet Approach

This assignment provides a practical exploration of the HTTP protocol using Telnet for analysis and testing. It covers the structure of HTTP requests and responses, including request lines, headers like Content-Type, and the process of bundling CGI GET parameters. The assignment details how to use Telnet to simulate HTTP GET requests, download files, and interact with a simple server (netSrvDemo). It further includes testing scenarios, such as handling incorrect request lines, unsupported methods, and file access errors, illustrating how a server responds to various client inputs. The document explains the difference between text/html and application/html content types. Desklib is a valuable resource for students seeking similar solved assignments and study materials.

Part 1: HTTP
 “Fields” or “words” of a request line’s purpose in each case
The division of request line is made in 3 parts:
Method request target HTTP-version:
This method is used for indication of the request for the performance on the resource target.
Use of the GET method can be done in case the user wants retrieval of any information from
the server.
The Request target’s purpose is allowing the server, the identification of the target resource
on which the application of request is done. It can have the form of absolute form or origin
form.
The HTTP version can be 1.0 or 1.1 and its purpose is an indication of the version of HTTP
protocol that is used by the client (Reschke, 2017).
 Describe the procedure of bundling the CGI GET parameters into the request URL.
The CGI GET parameters request is bundled under the string query URL. The string of the
query is contained with the values of a parameter that is followed by “=” and further it is
followed by the value of the parameter. Example param2= 200. Use of “&” is made for
separating the multiple parameter bundles from each other. Example
param2=100&param1=100.
 Describe percent encoding.
Use of percent-encoding is done to the conversion of request-target URL into the ASCII
supported format. Hence, the URL that has characters which are not supported in the URL is
converted to “%” which is further followed by two hexadecimal digits. Example, a character
space converts to %20 while percent encoding.
 Each “words” or “fields” purpose of a response line.
The division of the response line is done in 3 parts again:
HTTP version status-code reason-phrase
 Explain the Content-Type header. What is the difference between "text/HTML" and
"application/HTML"?
It specifies the resource’s media type. It explains to the client that what is the actual type of
the content which is sending to them. The "application/html" needs processing and
"text/html" doesn’t need extra processing to give the respond of content.

Part-1: Observing HTTP in action
 The operations which are the part of the HTML process of downloading, but now we use
Telnet command for those operations to perform. This is supposed to be a series of GET
commands.
 To start the process and establishing a connection, instead of its default port 23, it uses
port 80 of the website.
 We use command for terminal-> $ telnet example.com 80
 Then we enter this request with the use of host reader-
GET /index.html HTTP/1.1
Host: www.example.com
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 Download the file “wontBeThere.html” from http://bology.com.au. By using Telnet.
 Then we use this command to enter in terminal:
$ telnet bology.com.au 80
 Then enter the request with use of host reader-
GET /wontBeThere.html HTTP/1.1
Host: bology.com.au
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(Fielding, and Reschke, 2014).
netSrvDemo
 There is a command to build and to test the netsrvdemo-
 Go to the terminal window.
 Search the folder where netSrvDemo.c exists.
 Then to compile the server enter below command-
$ make
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 Then we use this command to run the server-
$ ./netSrvDemo
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 To connect with a specific server in other terminal window, we use this command:
$ telnet localhost 9991
- Then enter any text for ex.- “hey there?”

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 Main() function from netsrvdemo.c
Programming code
Part-2: Testing
There are some cases of Testing in this-
 When we enter request line with wrong numbers.
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 When the request doesn’t belong to “GET”
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 When we don’t enter a right path in the requested file.
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 When the configuration directory doesn’t have the file.
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 When our requested file delivers successfully.
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References
 Reschke, J., 2017. Indicating Character Encoding and Language for HTTP Header Field
Parameters (No. RFC 8187).
 Fielding, R. and Reschke, J., 2014. Hypertext transfer protocol (HTTP/1.1): Message syntax and
routing (No. RFC 7230).