I am using drupal7. i want to enable the clean url option. But the option is not showing there and below message is displayed
Clean URLs cannot be enabled. If you are directed to this page or to a Page not found (404) error after testing for clean URLs, see the online handbook.
And there is a Run the clean URL test is there. but clicking on that displays following failed message
The clean URL test failed.
So please let me know whether any module is needed for this or how to enable this.