I am designing a process for users (some on a company LAN and some on internet) to upload files to a third party's FTP server. The critical requirement is to enforce a secure (FTPES) connection to the server. I am recommending the FileZilla client but as FTES is an optional setting I can only request the users create secure FTP connections - can't force them to. I should mention here that the FTP server belongs to a third party provider and if there are server settings to enforce FTPES connections, we can't get these enabled.
My idea is to set up an FTP Proxy server that acts as a wrapper to the third party server and which only accepts FTPES connections.
So, has anyone heard of an FTP Proxy server that can do this? The closest I have found after hours of scouring the web is Kiesoft Advanced FTP Server, but this only runs as a desktop app, not as a service.