.---------------.               .------------------.
 | FTP Client    |               | Apache Listening |            .----------.
 | with HTTPS    |---------------| for SSL          |            | FTP      |
 | over SSL      |    SSL conn.  |                  |            | Server   |
 | Proxy support |-------------------.           .---------------.          |
 |               |       FTP conn    |<-CONNECT->|    FTP conn.  |          |
 |               |-------------------'           '---------------'          |
 |               |               |                  |            |          |
 |               |---------------|                  |            |          |
 |               |               |                  |            '----------'
 '---------------'               '------------------'