The most common method for getting your website files from your computer to the web server is called File Transfer Protocol (FTP). Protocol in computer science means a standard procedure for regulating data transmission between computers. There are numerous applications available to transfer files using the FTP protocol. Dreamweaver utilizes an FTP client for remote server connections.
When your FTP client first connects to the web server, it establishes a control session. Control sessions allow the FTP client and server to pass commands to each other (such as change directory, upload file, and delete folder). Your FTP client uses ports to access a web server. Numbers are used to represent ports. Port 21 is the default port that FTP servers use to receive information. FTP clients typically have a method to specify the port; port 21 is the default port. For information on setting up an FTP connection, refer to Set options for FTP connections in the Dreamweaver CS5 Help.
A firewall acts as a security measure to prevent unauthorized access to a computer network. To access the Internet applications may require special configuration options. If a firewall is preventing the connection, the most common error message is the "Cannot make connection to host" error message.
Passive FTP makes the FTP client establish all connections to the FTP server, as opposed to the web host supplying the return port. Firewalls typically allow passive FTP connections without requiring additional configuration information. For information on using Passive FTP, refer to step 13 in Set options for FTP connections in the Dreamweaver CS5 Help. Passive FTP can slow down the connection process.
For information on setting up an FTP connection, refer to Set options for FTP connections in the Dreamweaver CS5 Help.