If I have domain A.com with an established set of pages indexed in Google for a year. All my backlinks are to A.com as well. I set up domain B.com (same content in A.com, just redesigned). I am afraid of duplicate indexing by Google. So.. I shut down A.com and did a 301 redirect to B.com with a mask on it so that the url always looks like A.com when coming to the site from that url. However you can also navigate the site with from B.com. Google will index A.com and B.com with duplicate content. How do I make sure B.com (where the content physically lives) isn't indexed and make sure Google indexes it as A.com as it always previously had. A secondary question is whether the masking is a no-no for Google.