Redirecting All Sub-Domains
The first step to redirect a www. sub-domain to the root so that it always resolves to just the domain is to download the IIS Manager. This is assuming you do not have direct access to the server and are using Windows as your server. After this, the account that is going to access IIS needs premission granted. After logging in, go the the globe icon under the connections section and select: Connect a Site. After this I put in my Server name and Site name as my domain name and click Next. Then I authenticate with my username and password to the account and click next and after it connects, Finish.
From here I go into the Feature View of the IIS control panel and select URL Rewrite. Next I will click on the Action: Add Rule(s) and select: Canonical Domain. A list of options are provided to me and I will select: mouthguardstore.com. This default pattern is good for redirecting all sub-domains to the root.
Limiting Redirects To Only WWW.
The default pattern does not allow for other sub-domains which I have, such as: http://snoring-and-sleep-apnea.mouthguardstore.com/. I don't want that to redirect to the root of the application because those are actual pages. I'll have to edit the rule that was created and change it to: Check if input string: Matches the Pattern (to prevent an infinite loop) and then set the pattern from: ^.mouthguardstore\.com$ to ^www.mouthguardstore\.com$ so that it redirects all www. prefixed URLs to their non-www. counter part. Now I have consolidated all the URLs so that only one document exists for the content requested in a www. or non-www situation.