As to the FTP server we used OpenSSH. No, this is not an offer to write more than that.
The yes part is that I used filezilla to move files to and from OpenSSH and putty. Again, this is only to share the names for you to do further research.
We are a company in New York that deals with Medical Billing. Data from our clients usually came from either paper or later we set up an FTP site with an outside provider. But since HIPAA, I am getting more and more requests for a secure ftp site. Is this just a matter of using encryption keys and can the other user still use Filezilla?