Internet Engineering Task Force (IETF)                  R. Fielding, Ed.
Request for Comments: 7231                                         Adobe
Obsoletes: 2616                                          J. Reschke, Ed.
Updates: 2817                                                 greenbytes
Category: Standards Track                                      June 2014
ISSN: 2070-1721


        Hypertext Transfer Protocol (HTTP/1.1): Semantics and Content

Abstract

    The Hypertext Transfer Protocol (HTTP) is a stateless application-
    level protocol for distributed, collaborative, hypertext information
    systems.  This document defines the semantics of HTTP/1.1 messages,
    as expressed by request methods, request header fields, response
    status codes, and response header fields, along with the payload of
    messages (metadata and body content) and mechanisms for content
    negotiation.

 
RFC 7231             HTTP/1.1 Semantics and Content            June 2014


6.5.4.  404 Not Found

    The 404 (Not Found) status code indicates that the origin server did
    not find a current representation for the target resource or is not
    willing to disclose that one exists.  A 404 status code does not
    indicate whether this lack of representation is temporary or
    permanent; the 410 (Gone) status code is preferred over 404 if the
    origin server knows, presumably through some configurable means, that
    the condition is likely to be permanent.

    A 404 response is cacheable by default; i.e., unless otherwise
    indicated by the method definition or explicit cache controls (see
    Section 4.2.2 of [RFC7234]).




Fielding & Reschke           Standards Track                   [Page 59]