SERVER_SOFTWARE The name and version of the information server software answering the request (and running the gateway). Format: name/version
SERVER_NAME The server's hostname, DNS alias, or IP address as it would appear in self-referencing URLs.
GATEWAY_INTERFACE The revision of the CGI specification to which this server complies. Format: CGI/revision
SERVER_PROTOCOL The name and revision of the information protcol this request came in with. Format: protocol/revision
SERVER_PORT The port number to which the request was sent.
REQUEST_METHOD The method with which the request was made. For HTTP, this is "GET", "HEAD", "POST", etc.
PATH_INFO The extra path information, as given by the client. In other words, scripts can be accessed by their virtual pathname, followed by extra information at the end of this path. The extra information is sent as PATH_INFO. This information should be decoded by the server if it comes from a URL before it is passed to the CGI script.
PATH_TRANSLATED The server provides a translated version of PATH_INFO, which takes the path and does any virtual-to-physical mapping to it.
SCRIPT_NAME A virtual path to the script being executed, used for self-referencing URLs.
QUERY_STRING The information which follows the ? in the URL which referenced this script. This is the query information. It should not be decoded in any fashion. This variable should always be set when there is query information, regardless of command line decoding.
REMOTE_HOST The hostname making the request. If the server does not have this information, it should set REMOTE_ADDR and leave this unset.
REMOTE_ADDR The IP address of the remote host making the request.
AUTH_TYPE If the server supports user authentication, and the script is protects, this is the protocol-specific authentication method used to validate the user.
REMOTE_USER If the server supports user authentication, and the script is protected, this is the username they have authenticated as.
REMOTE_IDENT If the HTTP server supports RFC 931 identification, then this variable will be set to the remote user name retrieved from the server. Usage of this variable should be limited to logging only.
CONTENT_TYPE For queries which have attached information, such as HTTP POST and PUT, this is the content type of the data.
CONTENT_LENGTH The length of the said content as given by the client.
------------------------------------------------------------ In addition to these, the header lines received from the client, if any, are placed into the environment with the prefix HTTP_ followed by the header name.