Is it possible to block internal Drupal paths for anonymous users and leave only paths generated by pathauto? For example:

* block path: /taxonomy/term/5
* leave path: /products/books

In google webmaster tools for my site, all taxonomy pages have an issue called "**Pages with duplicate title tags**" and google is showing both paths for each term, which is a problem. How to block the internal Drupal path for anonymous users?

By the way, apart from this, some taxonomy terms are purely for config and their paths should be blocked not because googlebot has a problem but generally, those paths make no sense for non-admins and should never be accessed directly via url.