File Transfer Protocol (FTP)

The File Transfer Protocol, or FTP, is a network protocol used to exchange files between a client and a server. It operates with two separate connections, a control connection on port 21 for commands and a separate data connection for the actual transfer. A distinction is made between active and passive mode, with passive mode being standard in environments using firewalls and NAT. FTP transmits credentials and content without encryption, which makes it unsuitable for use across public networks. Secure alternatives include FTPS with TLS encryption and SFTP based on SSH. FTP continues to be used in internal networks, for firmware updates of network components and in legacy system environments, provided appropriate security measures are in place.