Redirect 404 allows you to specify a number of servers that should be attempted to be redirected to if a 404 (Page not found) error is encountered. This module is useful when you are doing a gradual migration to Drupal from another system (Drupal-based or not).
Description
Let's say you have a legacy system which contains most of your web presence and decide to migrate to Drupal, starting with the home page, but didn't want to orphan the legacy site. So, URL such as http://www.example.com/department would stop working and would return 404 to users visiting the site.
With mod_rewrite in Apache, it is possible to redirect 404 to an external URL, but it does not preserve the full request path nor support multiple destination servers.