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File transfer protocol

The File Transfer Protocol (FTP) is a part of the Internet protocol suite that is able to transfer computer files between machines with widely different operating systems.

It is an 8-bit protocol, capable of handling any type of file without further processing such as MIME or UUEncode. However, 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.

OSI model



Application layer FTP SMTP HTTP ...
Transport layer TCP UDP
Network layer IP ICMP ARP
data link layer Ethernet Token Ring FDDI ...

FTP is standardized in RFC 0959 by the IETF as:

FTP commonly runs on port 21.

The objectives of FTP are:

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

Disadvantages are:

  1. Passwords and file contents are sent in plaintext
  2. It is hard to filter FTP traffic using a firewall, since the data connection is made to an apparently arbitrary port
  3. It is possible to tell a server to send to an arbitrary port of a third computer

FTP, though usable directly by a user at a terminal, is designed mainly for use by programs.

Many sites that run FTP servers enable so-called "anonymous ftp". Users do not need an account on the server. They are asked to send their email addresses as their passwords, but there is no verification.

Table of contents
1 FTP and web browsers
2 See also
3 External Links

FTP and web browsers

Nowadays, web browsers can manage the FTP protocol, via a URL in the form ftp://<ftpserveraddress>  (e.g., [1]).

A username and password may also be added:  ftp://<login>:<password>@<ftpserveraddress>.

In GUIs such as MS Windows, one can create a so-called desktop shortcut for more easy access to FTP servers.

See also

External Links