How to add "rel=nofollow" to ALL external links? How to add "rel=nofollow" attribute to ALL external links....in Drupal 7?

So far I can find only with different filters and what not....

Before I was working with Joomla - I had a single plugin which was once set up - and wrapped ALL, completely all external links, wherever they would be - in Menus, articles, modules, social buttons, advertisements, etc....

I just cannot understand why would I need some Filter - the only Filtering option should be - it is an External link...

If I would know all external URL some scripts or users may add to my site - it would be great. But my experience shows - external URLs are almost always added secretly without me being aware of it; but it still should have "rel=nofollow"..
Have you tried this module : Noindex External Links

Module let's you take full control of external links indexing. Pages could also pass HTML-validation.


  Features
  
  Two methods of indexing control:
  
  
  Wrap links with NOINDEX tag. NOINDEX tag is used to deny indexing part of page. Only Yandex and Rambler considers this tag but Google
  and others doesn't. There is also an attribute NOINDEX in meta-tag
  Robots.
  Add attribute rel="nofollow" to links. This link's attribute has no effect on indexing. Only Google really do not follow this links but
  others do. Attribute is used to say to search engine that links no
  longer constitute a "vote" in the PageRank system.