ErrorDocument directive

In the event of a problem or error, Apache can be configured to do one of four things,

1. output a simple hardcoded error message
2. output a customized message
3. redirect to a local URL to handle the problem/error
4. redirect to an external URL to handle the problem/error

The first option is the default, while options 2-4 are configured using the ErrorDocument directive, which is followed by the HTTP response code and a message or URL.

Messages in this context begin with a single quote ("), which does not form part of the message itself. Apache will sometimes offer additional information regarding the problem/error.

URLs can begin with a slash (/) for local URLs, or be a full URL which the client can resolve. Examples:

ErrorDocument 500 http://foo.example.com/cgi-bin/tester
ErrorDocument 404 /cgi-bin/bad_urls.pl
ErrorDocument 401 /subscription_info.html
ErrorDocument 403 "Sorry can't allow you access today

Note that when you specify an ErrorDocument that points to a remote URL (ie. anything with a method such as "http" in front of it) Apache will send a redirect to the client to tell it where to find the document, even if the document ends up being on the same server.. This has several implications, the most important being that if you use an "ErrorDocument 401" directive then it must refer to a local document. This results from the nature of the HTTP basic authentication scheme.

See Also: documentation of customizable responses.