BASIC INTERNET PROTOCOLS: http, ftp, telnet.

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BASIC INTERNET PROTOCOLS http, ftp, telnet.

• Mirela Walczak

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Content

• Key Words
• Introduction
• Internet Protocol Suite
• Client Server Model
• OSI Model
• FTP Protocol
• HTTP Protocol
• TELNET Protocol

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Key Words

• Port
• Host
• Control stream
• Proxy
• SSL- secure sockets layer
• Client
• Server

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What is protocol?
Is a convention or standard that controls or
enables the connection , communication and data
transfer between two computing endpoints.
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Internet Protocols Suite

• The set of communication protocols used for
  Internet and other similar networks.

• Internet Protocol
• IP

• Transmission Control Protocol TCP

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OSI Model
OSI

• The Open Systems Interconnection Reference Model
• OSI Reference Model
• OSI Model
• OSI seven layer model

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TCP/IP Model OSI Model
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Client Server Model

• Software architecture model distinguishes
  Client system from Server system, which
  communicate over a computer network.

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The qualities characteristic for

• Server
• Passive
• It waits for the requests from the client
• When the request is received server process it
  and send an answer to the client

• Client
• Active
• It sends the request to server
• It is waiting for the answers from the server

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File Transfer Protocol

• Is a network protocol used for transfer data
  from one computer to another through a network
  such as Internet.

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Advantages of FTP

• FTP operates on two ports 21, 20
• Provides two different transfer mode
• Active client mode
• Passive server mode
• Servers can have anonymous FTP access
• Two formats on which data can be send
• ASCII mode-American Standard Code for
  Information
• Interchange
• BINARY mode

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ASCII mode
BINARY mode
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Disadvantage of FTP

• FTP is a high latency protocol for e.g to begin a
  transfer of data it has to be used many comands.
• Passwords and file contents are sent in clear
  text, allowing unwanted eavesdropping.
• It is possible to tell a server to send data to
  an arbitrary port of a third computer.

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The objectives of FTP

• To promote sharing of files (computer programs
  and/or data).
• To encourage indirect or implicit use of remote
  computers.
• To shield a user from variations in file storage
  systems among different hosts.
• To transfer data reliably, and efficiently.

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HyperText Transfer Protocol

• Is a communication protocol for the transfer
  of information on the Internet.

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Offices of the current Internet Engineering Task
Force Secretariat
World Wide Web Consortium World Wide Web Consortium

Type Consortium
Founded October 1994
Founder Tim Berners-Lee
Headquarters MIT/CSAIL in USAERCIM in FranceKeio University in Japanand many other offices around the world
Website www.w3.org -- History
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HTTP request method

• HEAD-Asks for the response identical to the one
  that would correspond to a GET request, but
  without response body.
• GET-Requests a representation of the specified
  resource.
• POST-Submitt data to be processed (e.g. from a
  HTML form) to the identified resource.
• PUT-Uploads a representation of the specified
  resource.
• DELETE-Deletes the specified resource.
• TRACE-Echoes back the received request, so that a
  client can see what intermediate servers are
  adding or changing in the request.
• OPTIONS-Returns the HTTP methods that the server
  supports.
• CONNECT-For use with a proxy that can change to
  being an SSL tunnel.

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HTTP Versions

• HTTP/0.9
• Support only one command GET and omits the
  header.
• HTTP/1.0
• This is the first protocol revision to specify
  its version in communications.
• HTTP/1.1
• Current version with persistent connection.
• Allows pipelining and multiple request at
  the same time.
• Works well with proxies
• HTTP/1.2
• Version from the 1995, later subsumed by the
  experimental HTTP Extension Framework

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Telecommunication Network Protocol

• Is a network protocol used on the Internet or
  local area network (LAN) connections.

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TELNET security

• Three main reasons why ..........?
• Does not encrypt any data sent over the
  connection (including passwords).
• Does not ensure that communication is carried out
  between the two desired hosts, and not
  intercepted in the middle.

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The packets allow easily obtain login and
password information.
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Current Status

• TELNET was replaced by SSH (Secure shell protocol
  with high level of encryption).
• Popular in enterprise networks to access host
  applications.
• Is also heavily used for games played over the
  Internet, as well as talkers.
• Cannot be used as a tunneling protocol.
• Should not be used on networks with Internet
  connection.

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SUMMARY

• PROTOCOLS are very important in successful
  communication.
• INTERNET PROTOCOL SUITE consist of two protocols
  IP and TCP. They are responsible for transmission
  data.
• OSI MODEL is an abstract description for layered
  communication and computers network protocol
  design. Consist of 7 seven layers.
• CLIENT SERVER MODEL is responsible for exchanging
  information between client and server .

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FILE TRANSFER PROTOCOL

• There are two computers involved in an FTP
  transfer a server and a client.
• Any software company or individual programmer is
  able to create FTP server or client software
  because the protocol is an open standard.
• There are many existing FTP client and server
  programs, and many of these are free.

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HYPERtext TRANSFER PROTOCOL

• Its original purpose was to provide a way to
  publish and retrieve HTML pages.
• Development of HTTP was coordinated by the World
  Wide Web Consortium and the Internet Engineering
  Task Force.
• HTTP is a request/response protocol between
  clients and servers.
• HTTP defines eight methods.
• HTTP versions 0.9, 1.0, 1.1, 1.2

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TELNET PROTOCOL

• Name is derived from the words telecommunication
  network.
• It was developed in 1969.
• Provides general, bi-directional, 8-bit
  communication.
• Client-server protocol with port 23.
• TELNET is not recommended for modern systems from
  the point of view of computer security.

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Sources

• http//en.wikipedia.org/wiki/Main_Page
• http//www.demon.net/helpdesk/technicallibrary/mis
  c/telnet/images/telnet.gif
• http//www.cyf-kr.edu.pl/mfjawien/FZI/Wstepx1.htm
  l
• http//www.angelfire.com/ab7/gregsgrl85/ftp.html
• http//www.cs.rpi.edu/academics/courses/fall96/net
  prog/lectures/html/ftp/tsld002.htm