When using SSL I can make the connection, but the list command says "cannot open data connection". Both the sending and target machines are behind firewalls.

Article Details

URL:	https://www.tbsoftinc.com/support/index.php?_m=knowledgebase&_a=viewarticle&kbarticleid=127
Article ID:	127
Created On:	08 Jun 2007 06:32 PM

Answer

If your computer is behind a firewall using NAT, it won't be able to interpret the PASV or PORT command relating to data transfer. You might want to try the Clear Command Channel (CCC) option under [Site Settings | Security] tab combined with the active mode (non-pasv). With such an option your FTP commands will be sent in clear text (of course password / user name are sent in encrypted form) so that firewall / router can see the client's port command and open that port for incoming connection. Data channel is still encrypted.