Some .htaccess code is supported on Acquia's managed Drupal platforms, while other .htaccess code is not. See below for details. 

Supported¶

• In the .htaccess provided by Drupal, we support everything Drupal requires, include Rewrites, which we have documentation about for redirects.
• The use of environment variables in .htaccess.
• Restricting access in various ways.

Unsupported ¶

• Options +Indexes which on other platforms will list the files inside a directory. That will not result in an error, but due to security concerns it will have no effect.
• DirectoryIndex is also not supported for the same reason.