Port 21: the default setting
Because most Web servers set aside Port 21 to receive connections from FTP clients, Dreamweaver is also configured to access Port 21 to upload files.
Choosing another port for FTP access
Sometimes, however, server administrators change the port setting of 21 to another port to prevent unauthorized FTP access. In those situations, Dreamweaver can be set to access a different port by adding the port number to the end of the FTP host name, as outlined below:
Configuring Dreamweaver to access an FTP port other than Port 21