Dave Dash has shared his tips on moving things smoothly from your development to production environments when using symfony and the Apache mod_rewrite module.

I think a common problem for some symfony developers that aren't too familiar with Apache's Mod Rewrite is when they move from a development environment that uses an explicit controller (e.g. frontend_dev.php is requested from the server explicitly) to their production app which implicitly calls index.php (e.g. '/' or some other route is passed to index.php) things stop working.

To combat the situation is easy - it's a simple update to the .htaccess file default to symfony to add a LoadModule line to start up mod_rewrite.