Error page
An error page is a website that is displayed if, for example, one clicks on a dead link on the Internet or calls up a non-existent URL . Most browsers show the standard page supplied by the web server ; an exception is Microsoft's Internet Explorer , which instead displays its own page, which sometimes makes troubleshooting much more difficult. Error pages can be created individually by the webmaster of the page. In the case of web servers that are operated with the Apache software, the content of the htaccess file on the web server determines which page is output with which HTTP status code (see next paragraph). Internet Explorer only displays these if the size is over 512 bytes.
Error pages are mostly categorized using HTTP status codes. The most common and therefore best known error codes are 404 "not found" and 500 "internal server error". The status codes from 400 onwards concern client errors with errors in the request, the status codes from 500 on server errors with apparently valid requests that the server cannot answer.
HTTP status codes
Common error messages in English and German:
- 4xx: Client error
- 400: Bad Request, Bad Request, Invalid Request; Incorrect syntax or unknown characters in the request
- 401: Unauthorized, unauthorized, access denied; mostly password protected, login
- 403: Forbidden, Forbidden, Inadmissible; Access blocked for the user's computer
- 404: Not Found; Document removed, moved, or renamed
- 410: Gone, No more resources can be reached under the specified URI and no forwarding address is known
- 5xx: Server error
- 500: Internal Server Error, Internal Error, Internal Server Error; z. B. Malfunction of a CGI script, process crash, resource bottleneck
- 501: Not Implemented, Not Implemented; Required functionality or requirement on the server does not exist
- 502: Bad Gateway, gateway error; Invalid response from another server in gateway or proxy mode
- 503: Service Unavailable, temporarily unavailable; Server overloaded, down or under maintenance