Is there any open source/commercial FTP client which supports FTPS (FTP over SSL/TLS) over firewall/proxy? Since If we use SSL/TLS, the Control channel is encrypted and the Firewall couldn't understand the port used for data communication. But, If we use passive mode, is this limitation can be addressed?
Filezilla supports FTPS.
IF you configure Filezilla to use a very restricted set of ports, and open those in the firewall, then that should get around the issue with the control channel?