Add-on domain is an independent domain but behaves like a sub-domain

Does it affect SEO?

[KFish]

I recently changed my web host and created an account maindom.com. This is a Linux server.

Since this is a multiple domain hosting, I set up a new domain (add-on domain) called newdomain.com

When I access newdomain.maindom.com I can see index.html page of newdomain.com.

I contacted my hosting provider and told them this. They said it’s perfectly ok and most multiple domain hosts do the same thing. It’s a very popular web-hosting company.

My major concerns are:

1.Will this affect my search engine ranking? If yes, will all my sites be affected?
2.What can I do to tell search engines that newdomain.maindom.com is non-existent and newdomain.com is an independent domain and so is maindom.com?
3.Is the answer I got from my host true? Does anyone know the technology behind multiple domain hosting and how it is done?

[jdMorgan]

You need to canonicalize your domain names and URLs. Use mod_rewrite, for example, to redirect requests for anything except newdomain.com or maindomain.com to the appropriate 'corrected' domain.

This will prevent duplicate-content issues from diluting your pages' ranking in search listings.

This subject is widely-covered here, and a search of WebmasterWorld for "canonical redirect" will likely turn up dozens or even hundreds of threads.

Jim

[Quadrille]

Look at the sites as a visitor would see them; if the set up is OK, then you do not have a problem.

But follow jdMorgan's advice to be sure you've seen all the possibilities that could lead to duplicate URL issues.