Mod_rewrite is an Apache web server module installed on all of our Linux servers by default; it does not have to be installed or enabled. Our Linux hosting accounts support most mod_rewrite functionality.
Mod_rewrite manipulates browser-submitted URLs and translates them to deliver content to the browser. This process takes places entirely server-side and without the browser's knowledge. The resulting content appears to have originated from the submitted URL, much like masking. However, this functionality is different from that of classic redirection, which simply points a browser to a different web server location.
Because mod_rewrite effectively disguises how and from where content is served, it can increase Website security. It also benefits Websites that utilize search engines, since search engines work best with static URLs. Mod_rewrite removes the dynamic portion of the URL, effectively making it static, thus preventing potential conflicts and increasing Website visibility.
For additional information on mod_rewrite, see How do I use mod_rewrite?