Subdomain content indexing duplicate

[rteeples]

When I assign a new domain to my bluehost account it automatically assigns a subdomain address. If I register newsite.com, it automatically creates newsite.oldsite.com.

I've never had a problem with this until I noticed Google is indexing both the newsite.com/whateverarticle as well as newsite.oldsite.com/whateverarticle.

Did I do something to cause this? Anyone know of a way to prevent it?

[felgall]

The sub-domain is necessary because of the way the stats programs work with shared hosting.

To prevent the search engines listing the sub-domain in the first place you should name the subdomain completely differently to the domain and not link to it. No search engine will guess that just because wondersite.com exists that gdan4.example.com also exists and has apparently duplicate content.

If search engines do pick it up because you accidentally linked to the subdomain instead of the domain then you could set up a 301 redirect of the entire subdomain in your .htaccess file.

[benlavery]

As felgall says 301 redirect would probably be your best option. You can also change robots.txt and disallow the subdomain.