What is FTP (File Transfer Protocol)?

Meaning & Definition

FTP (File Transfer Protocol)

FTP, or File Transfer Protocol, is a standard network protocol used for transferring files from one computer to another over a TCP/IP-based network, such as the Internet or a local network. FTP is a fundamental and widely used method for uploading, downloading, and managing files on remote servers and systems. It allows users to access, retrieve, and upload files to and from a remote server in a structured and efficient manner.

Here are some key aspects of FTP:

  • Client-Server Model

FTP operates on a client-server model, where one computer (the FTP client) initiates a connection to another computer (the FTP server) to transfer files. The client sends requests to the server to perform various file operations.

  • Authentication

To access an FTP server, users typically need to provide valid credentials, including a username and password. Some FTP servers may also support anonymous access, where users can log in with a generic or guest username without a password.

  • Commands

FTP uses a set of commands and responses to control file operations. These commands include functions like listing directories, uploading files (put), downloading files (get), renaming files, and deleting files.

  • Modes

FTP supports different transfer modes, including ASCII mode for text files and binary mode for non-text files like images, executables, and compressed archives. The transfer mode must match the type of file being transferred to ensure data integrity.

  • Passive and Active Modes

FTP can operate in passive or active mode, depending on the network configuration. Passive mode is commonly used when the client is behind a firewall or NAT device, while active mode is used when the client can accept incoming connections.

  • Security

FTP was originally designed without built-in encryption, making it vulnerable to eavesdropping. To address this, FTPS (FTP Secure) and SFTP (SSH File Transfer Protocol) were developed as secure alternatives that use encryption and secure authentication methods.

  • Port Numbers

FTP uses well-defined port numbers. The default FTP port is 21 for the control connection, and data transfers may use additional ports. Passive mode, in particular, uses a range of dynamically allocated ports for data transfer.

  • File and Directory Operations

FTP allows users to navigate remote directories, create, rename, and delete files and directories, and manage permissions on the server, depending on the user’s access rights.

FTP is widely used for various purposes, including website maintenance (for uploading and managing web content), data backup and synchronization, software distribution, and sharing files across networks. While traditional FTP lacks built-in security, organizations often use secure FTP alternatives like FTPS or SFTP to protect data during transit. Additionally, many modern file transfer methods and protocols, such as HTTP, HTTPS, and cloud-based file storage solutions, have gained popularity, offering enhanced security and ease of use.