Apache will return 403 (Forbidden) instead of 404 (Not Found) if the
`Indexes` option is turned off.  This is because with `Indexes` turned on,
it considers it something it *might* be able to serve in the future.  With
`Indexes` off, it will never serve that page in the future (unless
`Indexes` is turned back on).

The [[404 plugin|plugins/404]] code only checks for 404, not 403.  It should check for both.

> There are plenty of reasons a web server might 403. In most of those
> cases, trying to create a page where the forbidden content is is not the
> right thing for ikiwiki to do. --[[Joey]]

See Also:

 * [StackOverflow: 404-vs-403](http://stackoverflow.com/questions/5075300/404-vs-403-when-directory-index-is-missing)
 * [[404 plugin discussion|plugins/404/discussion]]
