Glossary.

FTP

File Transfer Protocol. Defined in RFC 959.

FTP Client

Program that connects to the FTP server, sends requests that follow FTP protocol to that FTP server, and interprets the responses received.

FTP Server

Program, usually running in a background, that waits for connection from FTP client and then serve the client by responding to requests received from the client side.

Local Site

Linux box you are running FTP client from. Generally may differ from the host that displays the program window.

Remote Site

The site, FTP server is running on that you are connected to. May very well be on the same host as a Local Site.

Control Connection

Connection between FTP client and FTP server used to send and receive requests and responses.

Data Connection

Connection usually established between FTP client and FTP server by request from the Client. Used to transfer "data" rather than requests/responses. An example of "data" would be directory listing or contents of the file being transfered.

Passive Transfer

One of the ways to establish Data Connection. Client side requests the Server to accept Data Connection, receives information on what address to connect to, and then establishes Data Connection by connecting to the server. Usually the only way to go if you are behind the firewall.

Firewall

A host that connects your local network to the global Internet. May impose some restrictions on type of the Internet services allowed to pass through.