FTP error 425 Cannot open data connection.

When connecting to the FTP server, if you get the error "425 Cannot open data connection." or "Could not retrieve directory listing"

This is becuase you need to enable PASV mode within your FTP software.

We are behind a firewall so "Passive Mode" must be enabled on your client. 

Check ports 50000-50004 are open. And of course port 21 ! 

During FTP login, if working correctly, you should see the command:

227 Entering Passive Mode (95,128,129,36,195,x) 

In dreamweaver, under Site Definition > remote info and then tick "Use Passive FTP"