HTTP 404 Error Page

404 errors should not be confused with DNS errors, which appear when the given URL refers to a server name that does not exist. A 404 error indicates that the server itself was found, but that the server was not able to retrieve the requested page.
Webservers can typically be configured to display a customised error page, including a more natural description, the parent site's branding or sometimes a search form. The protocol level phrase, which is hidden from the user, is rarely customized.
Internet Explorer (before Internet Explorer 7), however, will not display custom pages unless they are larger than 512 bytes, opting to instead display a "friendly" error page. Google Chrome includes similar functionality, where the 404 is replaced with alternative suggestions generated by Google algorithms, if the page is under 512 bytes in size.