HTTP Error Codes Reference

By Michael Bloch
Posted Tuesday, September 7, 2004

The jargon of the web has added many new words and terms to the English language.... way too many! - it's hard to keep up with the terminology, definition and explanations.

We've all hit those pages that give us mysterious error messages, so what do they mean? Below is a brief explanation of various HTTP Error codes. If you would like to decipher other information technologies terminology, try out our comprehensive glossary search box, located at:

(http://www.tamingthebeast.net/seng/whatis.htm)

Code Number Error Message Description
400 Bad Request The request could not be understood by the server due to incorrect syntax.
401 Unauthorized User authentication is required.
403 Forbidden The server understood the request, but is refusing to fulfill it.
404 Page Not Found The server has not found anything matching the Request-URI.
405 Method Not Allowed The method specified in the Request-Line is not allowed for the resource identified by the Request-URI.
406 Not Acceptable The server cannot generate a response that the requestor is willing to accept.
407 Proxy Authentication Required This code is similar to 401 (Unauthorized), but indicates that the client must first authenticate itself with the proxy.
408 Request Timed Out The server stopped waiting for a client request.
409 Conflict The request could not be completed due to a conflict with the current state of the resource.
410 Gone The requested resource is no longer available at the server and no forwarding address is known. This condition is similar to 404, except that the 410 error condition is expected to be permanent.
411. Length Required The server requires a content-length in the request
412 Precondition Failed The precondition given in one or more of the request-header fields evaluated to false when it was tested on the server.
413 Request Entity Too Large The server is refusing to process a request because the request entity is larger than the server is willing or able to process.
414 Request URL Too Long The server is refusing to service the request because the Request-URI is longer than the server is willing to interpret.
415 Unsupported Media Type The server is refusing to service the request because the entity of the request is in a format not supported by the requested resource for the requested method.
500 Server Error Internal Web server error
501 No Server Function not implemented in Web server software
502 Server Overload Bad Gateway; a server being used by this Web server has sent an invalid response.
503 Service Unavailable Service unavailable because of temporary overload or maintenance.
504 Gateway Timeout A server being used by this server has not responded in time.
505 HTTP Version Not Supported The server does not support the HTTP protocol version that was used in the request message.

About the Author
Michael Bloch
michael@tamingthebeast.net
(http://www.tamingthebeast.net/)
Tutorials, web content and tools, software and community. Web Marketing, eCommerce & Development solutions.