Sam Ingalls
Last Updated March 11, 2022 6:42 am

The File Transfer Protocol (FTP) is a communication protocol providing for the transfer of files between remote devices and a server across a local (LAN) or wide-area network (WAN) like the internet. FTP servers and software were crucial to the development of early networking in the last quarter of the 20th century and served as a precursor to more secure alternatives like FTPS and SFTP. Today, FTP has become less popular with cloud storage and sharing.

This article looks at the file transfer protocol’s definition, features, vendors, uses, and history.

What is FTP?

The File Transfer Protocol is a network protocol for transferring files between remote computers through an intermediary FTP server. FTP follows the client-server model using authenticated connections between servers and client devices to receive and share files.

Modern file transfer protocol solutions implement more robust security for small and medium businesses (SMBs) up to enterprise organizations that manage volumes of large file transfers. These new iterations include:

Type Abbreviation Differentiation
FTP-SSL FTPS Extension of FTP provides support for SSL/TLS
SSH-FTP SFTP Protocol using Secure Shell to transfer files
Managed File Transfer MFT Advanced FTP services managed by a managed service provider (MSP)
Read more: Best FTP Server Software for Secure File Transfer | ServerWatch

FTP Features

  • Management console available through a desktop or web application
  • Authentication protocol functionality and encryption-in-transit and at rest
  • Failover and redundancy capabilities like backups or virtual storage
  • Support for advanced transfer options like FTPS and SFTP
  • Record and analysis of logged transactions and forensic reporting
  • Lightweight Directory Access Protocol (LDAP) and access control
  • Configuration management and automation via additional scripting privileges

What is FTP Used For?

The File Transfer Protocol offers organizations and individual users a means to store, share, and manage files and other data for a group of authorized users. Sharing files over the internet between remote devices is the most widespread use. One user may upload a file to an FTP server and then share it with another person via a URL.

The emergence of cloud service providers (CSP) offers internet users a convenient way to share files relative to FTP. In some instances, though, users may prefer to have their files hosted on a home server and use FTP to enable it.

A graphic of how FTP works connecting an FTP host server with clients over the internet.


Also read: How to install an FTP server and secure it with TLS | TechRepublic

How FTP Works

An FTP connection needs two parties to establish a communication network. To do this, a user must receive permission by providing credentials such as a username and password to the FTP server. A public FTP server may not require credentials to access their files in some cases.

There are two distinct communication channels while establishing an FTP connection:

  • Command Channel: The channel in which the instruction and response occur
  • Data Channel: The channel in which the data gets transferred

Along with communication channels, there are two modes in which FTP operates that determine how the data connection exists:

  • Active mode: To transfer a file, an authorized user will use the protocol to request creating changes in the server. In return, the server will grant access. Distribution in active mode may become problematic if a firewall protects the user’s machine. The firewall may not allow any unauthorized sessions from an external party.
  • Passive mode: Passive mode prevents the firewall issue mentioned above. In this mode, the user establishes both the command and data channel. The server listens rather than attempting to connect back to the user.

Top FTP Server Software

  • Cerberus
  • ExaVault
  • Files.com
  • HelpSystems
  • Microsoft
  • Panic
  • Progress Software
  • Rebex
  • SmartFile
  • SolarWinds
  • South River Technologies
Read more:Best File Sharing Software for 2022 | CIO Insight

The History of FTP

MIT computer scientist Abhay Bhushan first published RFC 114 detailing FTP and email protocols in April 1971. Bhushan’s work was integral to what would become the internet. The next decade led to the adoption of the Transmission Control Protocol and Internet Protocol (TCP/IP), which formalized direct and indirect access with a remote host.

Abhay Bhushan at MIT.
Abhay Bhushan at MIT.

During the mid-1980s, FTP was adopted en masse to send and receive files in text-based computers and networks. It existed as one of the original applications for accessing information over the internet before the widespread use of HyperText Transfer Protocol (HTTP) for accessing web pages. A personal computer web browser can access FTP servers to transfer files, and virtually every computer platform supports the protocol.

Traditional FTP solutions are outdated today, but the industry is alive with more advanced file transfer protocols, including FTPS, SFTP, and HTTPS. In a sign of the protocol’s decline, Google Chrome deprecated support for FTP in November 2020.

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