An issuer of Security Certificates used in SSL connections.

See Also: Security Certificate, SSL

(Common Gateway Interface) - A set of rules that describe how a Web Server communicates with another piece of software on the same machine, and how the other piece of software (the “CGI program”) talks to the web server. Any piece of software can be a CGI program if it handles input and output according to the CGI standard. Usually a CGI program is a small program that takes data from a web server and does something with it, like putting the content of a form into an e-mail message, or turning the data into a database query. You can often see that a CGI program is being used by seeing “cgi-bin” in a URL, but not always.

See Also: cgi-bin, Web

The most common name of a directory on a web server in which CGI programs are stored. The “bin” part of “cgi-bin” is a shorthand version of “binary”, because once upon a time, most programs were refered to as “binaries”. In real life, most programs found in cgi-bin directories are text files - scripts that are executed by binaries located elsewhere on the same machine.

See Also: CGI

A software program that is used to contact and obtain data from a Server software program on another computer, often across a great distance. Each Client program is designed to work with one or more specific kinds of Server programs, and each Server requires a specific kind of Client. A Web Browser is a specific kind of Client.

See Also: Browser, Server

The most common meaning of “Cookie” on the Internet refers to a piece of information sent by a Web Server to a Web Browser that the Browser software is expected to save and to send back to the Server whenever the browser makes additional requests from the Server.

Depending on the type of Cookie used, and the Browser’s settings, the Browser may accept or not accept the Cookie, and may save the Cookie for either a short time or a long time.

Cookies might contain information such as login or registration information, online “shopping cart” information, user preferences, etc.

When a Server receives a request from a Browser that includes a Cookie, the Server is able to use the information stored in the Cookie. For example, the Server might customize what is sent back to the user, or keep a log of particular user’s requests.

Cookies are usually set to expire after a predetermined amount of time and are usually saved in memory until the Browser software is closed down, at which time they may be saved to disk if their “expire time” has not been reached.

Cookies do not read your hard drive and send your life story to the CIA, but they can be used to gather more information about a user than would be possible without them.

See Also: Browser, Server