THE APACHE SOFTWARE FOUNDATION

The Apache HTTP Server handles requests in several phases. At each of these phases, one or more modules may be called upon to handle that portion of the request lifecycle. Phases include things like URL-to-filename translation, authentication, authorization, content, and logging. (This is not an exhaustive list... First, it uses the URL-to-filename translation hook, which occurs after the HTTP request has been read, but before any authorization starts. Secondly, it uses the Fixup hook, which is after the authorization phases, and after per-directory configuration files ( files) have been read, but before the content handler is called... So, after a request comes in and a corresponding server or virtual host has been determined, the rewriting engine starts processing any directives appearing in the per-server configuration. (i.e., in the main server configuration file and sections.) This happens in the URL-to-filename phase.