VARIABLE MEANING
GATEWAY_INTERFACE The version of CGI that the server supports. This might be CGI/1.1.
SERVER_NAME The Internet domain name of the server.
SERVER_PORT The port number that the Web server is using.
SERVER_PROTOCOL The name and version of the protocol with which the client sent this request.
SERVER_SOFTWARE The name and version of the Web server software. This might be NCSA/1.3.