By default, MFFTP uses the host's default FTP client for transfers. To support a third party client - for example, to provide FTPS support - it must be possible to invoke the client from a standard command line. As there could be an infinite number of variations of the commands to invoke a third party client, you need a user-written module to generate and invoke them.
The following sections describe how to configure MFFTP to invoke a third party client, the parameter block that will be passed to the user module, and what is expected of it.