Canonicalization for www/non-www URLs and IP/domain on a Windows server

Question

I have checked my website using this SEO tool and the results report 2 issues:

Test your site for potential URL canonicalization issues. Canonicalization describes how a site can use slightly different URLs for the same page - for example: if www.mydomain.com and http://mydomain.com displays to the same page but do not resolve to the same URL. If this happens, search engines may be unsure as to which URL is the correct one to index. Learn more about canonicalization issues.

1. www.mydomain.com and mydomain.com should resolve to the same URL, but currently do not.

2. Your site's IP xxx.xxx.xx.xxx does not redirect to your site's domain name. This could cause duplicate content problems if a search engine indexes your site under both its IP and domain name. Consider using a 301 re-write rule in your .htaccess file so that your site's IP points to your domain name. Read more about canonical URL issues.

How can I configure my website to solve the 2 issues above? My website uses a Window server (ASP.net). I want to optimize for SEO, but first I must solve this.

Answer 1

Firstly, see the comment on my answer here. If you're not able to reach either the www or non-www URLs for your website, see the second part of my answer here. If you are able to reach both and they return the same content, then proceed with the following.

Assuming that you're using IIS (for ASP.net):

1.) Create a 301 redirect from either www.mydomain.com -> mydomain.com, or the reverse (either is fine, though many prefer the non-www version).

For IIS 7.x, as covered here the steps are:

• Download and install IIS URL Rewrite 2.0 if not currently installed
• Open IIS Manager and double-click on the “URL Rewrite” icon
• Click on “Add Rules…” from the Actions pane
• Name the rule you're about to create (i.e., “Redirect mydomain.com to www”)
• From the dropdown box select Wildcards
• Enter * for the “Pattern”
• Expand the “Conditions” section and click “Add”

• In the “Add Condition” dialogue enter the following:

  Condition input: {HTTP_HOST}
  Check if input string: Matches the Pattern
  Pattern: www.mydomain.com (or mydomain.com if www is prefered)
  Ignore case: checked

• Click OK

• In the Action section make sure that the “Action Type” is set to Redirect
• For the “Action Properties”, enter http://www.domain.com/{R:0} (or use mydomain.com if www is prefered)
• Be sure that the “Append query string” remains checked so that the querystring part is also retained
• Be sure that the “Redirect Type” is set to Permanent (301)
• Apply the rule and test

In Google Webmaster Tools, be sure to set your Preferred domain (www or non-www)

2.) See my answer here.

Lastly, it's always a good idea to do a little research to verify SEO advice, as there's lots of questionable information out there that can result in more work than is necessary, and sometimes result in additional problems for your site too.