What is Passive FTP?
Passive FTP is a connection between two servers, where the client service is the initiator of the connection on both sides; the client and the remote site. There are two types of file transfer protocols or FTP, active and passive. In a FTP, a data port (usually port 20) and a command or control port (usually number 21) is opened between two computers, allowing files to be moved between units through the firewall. To initiate the connection, the client must follow two steps, which are detailed below: 1)Open two unprivileged local ports. The first port is n > 1023 and is set to access port 21 on the server, using a PASV ftp command. The receiving server opens unprivileged port p > 1023 and a port p command is returned. 2)Open port n +1 and connect to port p on the server. Now the connection is made and the data transfer between the client and the server can begin. In order to support passive FTP, four settings on the server side firewall are required. FTP server port 2 and n > 1023 from
The most common method for getting your web site 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 many software applications (called FTP clients) that will assist you in such data transmission. Dreamweaver contains an FTP client.
