I host my sites on HOSTGATOR VPS with only one ip address, all my sites must be parked based on sub a sub domain of primary domain eg: my primary domain is www.abc.com my another websites is : www.123.com parked based on sub domain 123.abc.com Hoever Google keep indexing 123.abc.com cause duplicated content issue. How to block Google to index 123.abc.com????
don't know exactly if it would have help much more then your 301, or via a Robot.txt comment, but you could have had a look at a Network Configuration software.