may be the last-update timestamp of the record. For virtual objects,
   it may be the last time the internal state changed.

   An origin server must not send a Last-Modified date which is later
   than the server's time of message origination. In such cases, where
   the resource's last modification would indicate some time in the




 
RFC 1945                        HTTP/1.0                        May 1996


   future, the server must replace that date with the message
   origination date.

10.11  Location

   The Location response-header field defines the exact location of the
   resource that was identified by the Request-URI. For 3xx responses,
   the location must indicate the server's preferred URL for automatic
   redirection to the resource. Only one absolute URL is allowed.

       Location       = "Location" ":" absoluteURI

   An example is

       Location: http://www.w3.org/hypertext/WWW/NewLocation.html

10.12  Pragma

   The Pragma general-header field is used to include implementation-
   specific directives that may apply to any recipient along the
   request/response chain. All pragma directives specify optional
   behavior from the viewpoint of the protocol; however, some systems
   may require that behavior be consistent with the directives.

       Pragma           = "Pragma" ":" 1#pragma-directive

       pragma-directive = "no-cache" | extension-pragma
       extension-pragma = token [ "=" word ]

   When the "no-cache" directive is present in a request message, an
   application should forward the request toward the origin server even
   if it has a cached copy of what is being requested. This allows a
   client to insist upon receiving an authoritative response to its
   request. It also allows a client to refresh a cached copy which is
   known to be corrupted or stale.

   Pragma directives must be passed through by a proxy or gateway
   application, regardless of their significance to that application,
   since the directives may be applicable to all recipients along the
   request/response chain. It is not possible to specify a pragma for a
   specific recipient; however, any pragma directive not relevant to a
   recipient should be ignored by that recipient.

10.13  Referer

   The Referer request-header field allows the client to specify, for
   the server's benefit, the address (URI) of the resource from which
   the Request-URI was obtained. This allows a server to generate lists




 
RFC 1945                        HTTP/1.0                        May 1996


   of back-links to resources for interest, logging, optimized caching,
   etc. It also allows obsolete or mistyped links to be traced for
   maintenance. The Referer field must not be sent if the Request-URI
   was obtained from a source that does not have its own URI, such as
   input from the user keyboard.

       Referer        = "Referer" ":" ( absoluteURI | relativeURI )

   Example:

       Referer: http://www.w3.org/hypertext/DataSources/Overview.html

   If a partial URI is given, it should be interpreted relative to the
   Request-URI. The URI must not include a fragment.

      Note: Because the source of a link may be private information or
      may reveal an otherwise private information source, it is strongly
      recommended that the user be able to select whether or not the
      Referer field is sent. For example, a browser client could have a
      toggle switch for browsing openly/anonymously, which would
      respectively enable/disable the sending of Referer and From
      information.

10.14  Server

   The Server response-header field contains information about the
   software used by the origin server to handle the request. The field
   can contain multiple product tokens (Section 3.7) and comments
   identifying the server and any significant subproducts. By
   convention, the product tokens are listed in order of their