What is Passive FTP? (and where does Dreamweaver fit in?)

There is a way to get around the firewall difficulty. In "Passive" FTP your computer establishes the second connection, not the web server. Most, but not all, web servers will allow Passive FTP connection. Most firewalls will allow your computer to transfer files in this second connection to the web server (just as it allowed your computer to establish the first connection). The Dreamweaver FTP client has the option to establish Passive FTP.

Additional information

Here's a Macromedia Technote (15220) for more info.