basic internet protocols: http, ftp, telnet
DESCRIPTION
BASIC INTERNET PROTOCOLS: http, ftp, telnet. Mirela Walczak. Content :. Key Words Introduction Internet Protocol Suite Client Server Model OSI Model FTP Protocol HTTP Protocol TELNET Protocol. Key Words:. Port Host Control stream Proxy SSL- secure sockets layer Client - PowerPoint PPT PresentationTRANSCRIPT
BASIC INTERNET PROTOCOLS: http, ftp, telnet.
Mirela Walczak
Content :Key Words
IntroductionInternet Protocol Suite
Client Server Model OSI Model
FTP ProtocolHTTP Protocol
TELNET Protocol
Key Words:• Port• Host • Control stream • Proxy• SSL- secure sockets layer• Client • Server
What is protocol?
Is a convention or standard that controls or enables the connection , communication and data transfer between two computing endpoints.
Internet Protocols Suite The set of communication
protocols used for Internet and other similar networks.
• Internet Protocol IP
• Transmission Control Protocol TCP
OSI Model• The Open Systems
Interconnection Reference Model
• OSI Reference Model
• OSI Model • OSI seven layer
model
OSI
TCP/IP Model – OSI Model
Client Server Model Software
architecture model distinguishes Client system from Server system, which communicate over a computer network.
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 serverIt is waiting for the
answers from the server
File Transfer Protocol
Is a network protocol used for transfer data from one computer to another through a network such as Internet.
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
ASCII modeBINARY mode
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.
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.
HyperText Transfer Protocol
Is a communication protocol for the transfer of information on the Internet.
Offices of the current Internet Engineering Task Force Secretariat
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
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.
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/1.1Current 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
Telecommunication Network Protocol
Is a network protocol used on the Internet or local area network (LAN) connections.
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.
TELNET security
•The packets allow easily obtain login and password information.
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.
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 computer’s network protocol design. Consist of 7 seven layers.
• CLIENT SERVER MODEL is responsible for exchanging information between client and server .
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.
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
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.
Sources
• http://en.wikipedia.org/wiki/Main_Page• http://www.demon.net/helpdesk/
technicallibrary/misc/telnet/images/telnet.gif• http://www.cyf-kr.edu.pl/~mfjawien/FZI/
Wstepx1.html• http://www.angelfire.com/ab7/gregsgrl85/
ftp.html• http://www.cs.rpi.edu/academics/courses/
fall96/netprog/lectures/html/ftp/tsld002.htm