Using CCC (Clear Command Channel), your connection process and login are encrypted, but when you begin transferring data, all FTP commands are sent in clear text. The data transfers remain encrypted, unless you choose to use a clear data channel. SSL connections require CCC when connecting in PORT mode from behind a NAT firewall.
Click on a site in the Site Manager.
On the menu bar, click File > Properties. The Site Properties dialog box appears.
Click the Type tab.
In the Protocol list, make sure FTP with SSL (Implicit encryption), or FTP with SSL (Explicit encryption) is selected.
Select the Clear Command channel check box.
Click OK or Connect.
The Clear Command channel option is only available with SSL connections.
Using a clear data channel with SSL