File transfer resources

The File Transfer Protocol (FTP) specification was created to transfer files reliably and efficiently between incompatible computer systems.

FTP Basics provides an introduction to the File Transfer Protocol and the roles played by Server and Client side software to initiate file transfers.

FTP Commands that are issued by FTP Client software to communicate with a remote FTP server are listed with brief descriptions.

Technical Specifications relating to the implementation of the original FTP protocol and subsequent enhancements are covered in these IETF document releases.

FTP, SFTP and FTPS ports: the port numbers behind each protocol, the data connections FTP and FTPS open on top of them, and what to allow in a firewall.

SFTP vs FTPS vs FTP: how the three protocols differ, side by side, and when to use which.

FTP connection problems: passive mode, firewalls, proxies, timeouts and the reply codes behind them, with fixes.

FTP in Windows Explorer and the command prompt: what the FTP built into Windows can do, where it stops, and what a client adds.