404 Error Code
The HTTP 404 Error Code is popularly known as the “Not Found” Error. The 404 Error indicates that the system or the client can contact the server whereas the server is not able to contact the system or client in return. This may be due to the link being broken or dead due to obvious reasons, the page or post may be removed from the site, or the link may be altered by mistake. This makes the server throw a 404 Error to the user. The 404 Error is the most popular among the HTTP Errors on the internet. It is entirely different from the “Server Not Found” Error which occurs when the client server itself cannot establish a connection. It indicates that the server itself was found, but that the server cannot able to retrieve the requested page.
In the Error code, the first digit indicates a client error that is the mistyped link. The following two digits indicate the error more specifically. Often the 404 Errors are followed by a phrase for the readers to let know about the missing page. Most servers by default show an HTML page with a 404 and “Not Found” message.
Soft 404 Error Codes
A soft 404 Error page is a 404 error page but returns an HTTP status code 200. The page will look like “Page Not Found” but search engines will see and think that it’s an actual live page. Also in a soft 404 error code, the user either gets redirected to the home page or another custom page. For example, consider a site has a house for sale. Once the house is being sold the page now becomes a soft 404 error page.
404 Substatus Error Codes
The 404 Substatus Error Codes are codes that specify the most specific cause of the error. These are defined by the Microsoft’s Internet Information Services and is not specified by the IANA officially.
404.0 – Not found
404.1 – Site Not Found
404.2 – ISAPI or CGI restriction
404.3 – MIME type restriction
404.4 – No handler configured
404.5 – Denied by request filtering configuration
404.6 – Verb denied
404.7 – File extension denied
404.8 – Hidden namespace
404.9 – File attribute hidden
404.10 – Request header too long
404.11 – Request contains double escape sequence
404.12 – Request contains high-bit characters
404.13 – Content length too large
404.14 – Request URL too long
404.15 – Query string too long
404.16 – DAV request sent to the static file handler
404.17 – Dynamic content mapped to the static file handler via a wildcard MIME mapping
404.18 – Query string sequence denied
404.19 – Denied by filtering rule
404.20 – Too Many URL Segments
404 CODE REFERENCES
The HTTP 404 Error Code References are listed below.
- Rails HTTP Status Symbol :not_found
- Go HTTP Status Constant http.StatusNotFound
- Symfony HTTP Status Constant Response::HTTP_NOT_FOUND
- Python2 HTTP Status Constant httplib.NOT_FOUND
- Python3+ HTTP Status Constant http.client.NOT_FOUND
- Python3.5+ HTTP Status Constant http.HTTPStatus.NOT_FOUND