The File Transfer Protocol (FTP) is an old and common Internet protocol. As the name implies, it's used to transfer files between computers. Clients can download files from or upload files to an FTP server, depending upon the server's configuration. In some situations, you may want to run an FTP server instead of or in addition to a Web server or a file-sharing server. In other cases, running multiple server types may be redundant. If you do decide to run an FTP server, there are several FTP server options for Linux. In most cases, these servers come with default configurations that work for certain purposes, but you may want to fine-tune the configuration. More radical changes may be required to run an anonymous FTP site, which allows anybody to download files from the server.