Forum Moderators: phranque
2) Internally rewrite requests for those friendly URLs, when they arrive at your server, to return content from the "unfriendly" internal filepaths (which are the same as before).
3) Optionally, externally redirect *only* direct client requests for the old unfriendly URLs, to the new friendly URLs. Do not redirect requests for unfriendly filepaths that are requested as the result of step 2 above.
Notice that before changing to using SEO-friendly URLs on your pages, your URLs and your filenames were "almost the same thing." After changing those URLs, they are no longer similar to the associated server filepaths, and mod_rewrite is used to 'map' the new URLs to the old filepaths.
Making the distinction that a URL is not a filename is very helpful in understanding the process.
See the details in this previous thread [webmasterworld.com] from our library [webmasterworld.com].
Jim