FTP (File Transfer Protocol)

FTP (File Transfer Protocol) is a standard protocol for transferring files between a client and a server over a network. It uses port 21 for commands and a separate connection for the data, in active or passive mode. FileZilla and WinSCP are common clients.

Plain FTP sends usernames, passwords and files unencrypted, so it has largely been replaced by SFTP (SSH File Transfer Protocol, port 22), which runs over an encrypted SSH connection, and FTPS, which is FTP secured with TLS.