An FTP server has two main meanings. It can either refer to the physical computer that is housing your website files and is allowing you to edit them. Or, an FTP server can refer to the application that runs on the computer and enables it to provide you with your website’s files on-demand.
You can connect to an FTP server using an FTP client. This forms a client-server model where the client connects to a server and sends a request. The server, in on the other hand, would process that request and send back a response containing the requested information. In the context of FTP, the FTP client would try to upload or download files from the server and the server would try to accommodate the client’s request.
FTP servers can be set up to allow two different types of clients to connect – anonymous and authenticated clients. The anonymous mode gives users free access to the FTP server via default “anonymous” account. Overall, this approach is discouraged as it offers zero security and accountability as to the changes performed by anonymous users. The authenticated mode requires password and account, of course. The FTP server could be configured to allow different levels of access, you can block users from entering certain directories or performing certain actions. You can also disallow some users from using your FTP server at all. If needed you can use secure connections like SFTP or FTPS.