HTTP 40x -- Client Error Codes

Applies To: Windows Server 2003, Windows Server 2003 with SP1

HTTP status codes in the 4xx range indicate that a problem occurred with the request. Request problems can range from the request not meeting authentication requirements to the request being malformed. RFC 2616, "Hypertext Transfer Protocol — HTTP/1.1", refers to request problems as client errors because the requests originate from the client. For more information about RFC 2616, see the W3C World Wide Web Consortium Web site.

Table 11.4   HTTP 400-Class Client Error Codes Returned by IIS lists the client error codes that IIS returns. The descriptions for most codes are self-explanatory. When additional information about a code is required, it is provided in one of the following sections.

Table 11.4 HTTP 400-Class Client Error Codes Returned by IIS

Status Code	Condition
400	Cannot resolve the request.
401.x	Unauthorized.
403.x	Forbidden.
404.x	File or directory not found.
405	HTTP verb used to access this page is not allowed.
406	Client browser does not accept the MIME type of the requested page.
407	Initial proxy authentication required by the Web server.
412	Precondition set by the client failed when evaluated on the Web server.
413	Request entity too large.
414	Request URL is too large and therefore unacceptable on the Web server.
415	Unsupported media type.
416	Requested range not satisfiable.
417	Expectation failed.
423	Locked error.