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What is FTP ?
FTP is the short form for File
Transfer Protocol, a standard Internet protocol, for exchanging
files between servers over the internet. FTP is a network
protocol. It is one of the most useful services of the internet.
There are two computers involved in an FTP transfer: a server
and a client. The FTP server, running FTP server software,
listens on the network for connection requests from other
computers, that is computers configured to accept FTP requests
are referred to as FTP servers. These servers store a tremendous
amount of information, and it is available to anyone on the
Internet using FTP, are also called host or remote computers.
The client computer, running FTP client software, initiates a
connection to the server.
Once connected,the client can do a number of file manipulation
operations such as uploading files to the server, download files
from the server, rename or delete files on the server and so on.
Client computers are also called local computers. Downloading
refers to transferring files from the FTP server to the client
computer. Uploading refers to transferring files to the FTP
server from the client computer. FTP is commonly used to
transfer Web page files from their creator to the computer that
acts as their server for everyone on the Internet. It's also
commonly used to download programs and other files to your
computer from other servers. FTP is most commonly used to
download a file from a server using the Internet or to upload a
file to a server (e.g., uploading a Web page file to a server).
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FTP is similar to Hyper Text
Transfer Protocol (HTTP), which transfers displayable web pages
and related files, Simple Mail Transfer Protocol (SMTP), which
transfers e-mail, in that it is an application protocol that
uses the internet’s TCP/IP protocols.
Objectives of FTP
1. To promote sharing of files. These can be computer programs,
textual or binary data.
2. To encourage indirect or implicit use of remote computers.
This is widely done nowadays but was rarer when FTP was
designed.
3. To shield a user from variations in file storage systems
among different hosts. Users need not worry about the types of
file systems used at either end of a FTP transaction, an obvious
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4. To transfer data reliably and
efficiently. It supports this last aim with more options and
functionality than the web protocol HTTP, which was designed
after it. File Transfer Protocol (FTP) powers one of the most
fundamental Internet functions: the transfer of files between
computers. Prior to 1995, FTP generated more traffic on the
Internet than any other service. Today, Web developers use FTP
protocols to upload/update their web sites and download other
information. FTP is an 8-bit client- server protocol, capable of
handling any type of file without further processing, such as
MIME or Uuencode. FTP is used to transfer all files needed for
the website to the web server, including HTML files, image
files, and audio/video files.
FTP
servers
Anonymous FTP-Having an FTP server on the Internet does not mean
everyone can access it. Some system administrators may choose to
restrict access to their files to a local or selected group of
users. Others administrators may choose to make all of their
files available to everyone. If it has no access restriction,
the FTP server allows any and every user to access its files;
these servers are called anonymous FTP servers. It still has a
logon procedure. It transfers files from the public portion of
an FTP server. Most anonymous FTP servers are set up to accept
"anonymous" as the user identification. For the password, they
accept, and sometimes require, the user's e-mail address.
Mirror Sites- Mirror sites are FTP servers that maintain an
exact copy of the files from one or more FTP servers. Accessing
a mirror site that is closer or less busy than the original site
can be advantageous to a user. By being closer, the file
transfer may involve fewer network connections and less network
traffic. This can help to make the file transfer faster. A less
busy server ensures a better chance of connecting.
FTP packages
There are many FTP packages available today, including
• Dedicated packages - These are stand alone software products
that help manage FTP needs.
• Built-ins - Many WYSIWYG software packages and browsers have
FTP services built right into the application.
Dedicated FTP packages offer capabilities that some built-in
components do not offer, such as the ability to delete old web
pages and rename files on the server.
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FTP
software
To transfer files between an FTP server and a desktop computer,
the local computer needs to be running FTP client software. All
these client programs orchestrate the file transfer
communications between the client computer and the FTP server.
Such programs include WS_FTP for the PC and Fetch for the
Macintosh. Each FTP program has its own interface, some more
intuitive and user-friendly than others. Whatever the program,
they all work the same way. The method for transferring files to
a web server is similar for each of these programs. After
starting, the first thing they require is an FTP server with
which the file transfer is to occur. The IP address or domain
name, identify the server to the program. Depending on the
server, it might also require a user identification code and
password. After the user enters a specific FTP server name or
address, the FTP program attempts to connect to the server. Most
FTP programs display the responses they receive from the server
when they are communicating with it.
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WS_FTP
The most popular FTP program for Windows is WS_FTP. WS_FTP is a
very powerful program allowing file types to be customized
(helpful when using lesser-known extensions) and viewed. WS_FTP
is available for all Windows platforms.
CuteFTP CuteFTP is a package
geared more toward beginners than WS_FTP since it has more
intuitive menus. CuteFTP also allows the user to set up
categories of configuration profiles, which can be helpful if
working on multiple sites. Another nice feature of CuteFTP is
the ability to resume uploads if the user gets disconnected
during transfer. CuteFTP is available in Spanish and Japanese.
Fetch for the macintosh
Fetch is a Macintosh based FTP program and is the most
convenient and popular program. . Its interface is extremely
user friendly making the FTP process especially simple for
novices.
Advantages of FTP
FTP is a very useful and valuable Internet service. A tremendous
amount of information and programs are available on the
Internet. FTP is the best way to transfer those files to one’s
computer. FTP provides an easy way to distribute information to
users locally, or worldwide. By putting your files on an FTP
server, they are available to everyone on the Internet. Some of
the advantages of using FTP are as follows
• FTP is one of the fastest and efficient ways to transfer large
amounts of data on the entire internet. It is thus the preferred
method of exchanging over HTTP.
• By using FTP, one can have an automatic backup. As one makes
changes, the files will be copied to the host's computer. This
means no matter what happens to the host, even if the computer
is totally destroyed, there exists a copy of the site on the
disk.
• FTP does not restrict the nature of information in the file,
eg, a file could contain ASCII text, binary data computer
program or any other information as needed. This is an advantage
over FrontPage, which does not give the choice.
Disadvantages of FTP
Some of the disadvantages of FTP are as follows:
1. FTP has extremely high latency; that is, the time between
beginning the request and starting to receive the required data
can be quite long, and a sometimes-lengthy login procedure is
required.
2. Passwords and file contents are sent in clear text, which can
be intercepted by eavesdroppers
3. Multiple TCP/IP connections are used, one for the control
connection, and one for each download, upload, or directory
listing. Firewall software needs additional logic to account for
these connections.
4. It is hard to filter active mode FTP traffic on the client
side by using a firewall, since the client must open an
arbitrary port in order to receive the connection. This problem
is largely resolved by using passive mode FTP.
5. It is possible to abuse the protocol's built-in proxy
features to tell a server to send data to an arbitrary port of a
third computer.
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Article Contributed By: Shaonli
Dasgupta
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