I have a .net site.
I want to create a .org site as an alias, so if user goes to example.org, the server will actually use the files that are on the original example.net site, but still keep .org in browser's address bar (so it is not a redirect).
However, I don't want the .org site to be indexed on Search engines (since it will be a "duplicate site"). So I want to a add a META NO INDEX tag at any case that the browser address belongs to .org rather than .net.
How may I check this with PHP, under these circumstances?