Set up a virtual FTP server with pam-mysql
Setting up a virtual File Transfer Protocol (FTP) server with a database back end offers many benefits. By using a database, you can store a large number of users centrally, so it’s easy to manage. It offers more security than traditional Unix OS authentication methods, because virtual users can access only the FTP server’s resources, not the OS’s. You can use the many Web tools that are available to easily install, configure, and manage the database back end. A virtual FTP server also supports some special characters, such as @, that FTP itself doesn’t support, which can come in handy if, for example, your company uses its employees’ email addresses for identity purposes.
NOTE: pam-mysql can be used to authenticate anything that supports pam authentication against a mysql database, not just your ftp server.