FTP (File Transfer Protocol)

FTP (File Transfer Protocol) is an application‑layer network protocol designed to transfer files between computers over a TCP/IP network. It uses a separate control channel (default port 21) and a data channel (traditionally port 20 or an ephemeral port negotiated by the server) and provides commands for navigation, uploading and downloading files. By default FTP sends credentials and data in plain text, making it insecure for sensitive transfers; more secure alternatives are FTPS (FTP over TLS/SSL) and SFTP (file transfer over SSH).

For example, to upload a static website to a shared hosting account you open an FTP client (e.g. FileZilla), enter the host, username and password, and drag the site files into the public_html folder. If you are behind NAT or a firewall you often need to enable 'passive' mode so the client initiates the data connection to a server‑specified port; without it data transfers frequently fail. For automated deployments you would typically prefer SFTP or FTPS today, because plain FTP transmits passwords in clear text and is unsafe on untrusted networks.