You can define the following ColdFusion server variables:

Client variables

Associate data with a specific client. Client variables maintain the application’s state as the user moves from page to page in the application, as well as from session to session. “Maintaining state” means to preserve information from one page (or session) to the next so that the application remembers the user, and the user’s previous choices and preferences.

Cookie variables

Access cookies passed to the server by the browser.

CGI variables

Provide information about the server running ColdFusion, the browser requesting a page, and other information about the processing environment.

Server variables

Can be accessed by all clients and applications on the server. They persist until the server is stopped.

Local variables

Created with the CFSET tag or CFPARAM tag within a ColdFusion page.