Solving Canonical Problems with WWW

One of the most common problems I see in websites is the same content being available at both the WWW and non-WWW versions of a domain. I’ve encountered this in nearly every website I’ve done an SEO audit for, and I see it every day when browsing the web. Despite it being so prevalent, it is indeed a problem.

Having the same content available on both the WWW and non-WWW versions of a domain (such as authoritylabs.com and www.authoritylabs.com) is called canonicalization. While you and I might realize they are in fact the same page, search engines mistake them to be unique pages.

Most of the time, search engines can figure out that they are the same page and only include the canonical URL in their index. SEObook explains the canonical URL as:

The canonical version of any URL is the single most authoritative version indexed by major search engines. Search engines typically use PageRank or a similar measure to determine which version of a URL is the canonical URL.

Regardless, canonicalization can result in indexing problems and duplicate content issues. Most importantly, canonicalization will split the link juice between each version as people link to and share both.

What you want to see is a redirection from the WWW to the non-WWW, or vice versa, so that if the wrong version is entered or linked to, the user is automatically taken to the canonical URL. Fortunately, this is relatively easy to set up.

Google Webmaster Tools

If you’ve verified your site with Google Webmaster Tools, you can set your preferred domain by going to Site Configuration > Settings, and selecting either ‘Display URLs as www.yourdomain.com’ or ‘Display URLs as yourdomain.com’.

This will make sure that Google only indexes your preferred canonical URL. However, it doesn’t fix the problem of splitting your link juice so you should still set up a redirect using one of the following methods.

 

Redirect Using .htaccess

If your site is hosted on Apache, you can redirect from the WWW to the non-WWW, or vice versa, with a few lines in your .htaccess file.

Redirect WWW to non-WWW:

RewriteEngine On
RewriteCond %{HTTP_HOST} !^(yourdomain\.com)?$
RewriteRule ^(.*)$ http://yourdomain.com/$1 [R=301,L]

Redirect non-WWW to WWW:

RewriteEngine On
RewriteCond %{HTTP_HOST} !^(www\.yourdomain\.com)?$
RewriteRule ^(.*)$ http://www.yourdomain.com/$1 [R=301,L]

 

Redirect Using cPanel

aka The Lazy Way to Redirect Using .htaccess

If your website is hosted with a provider that uses cPanel, you can even set up your redirects without touching a line of code. This actually adds the redirect rule directly to the .htaccess file, but sometimes I’d rather not get my hands dirty. To do this, log in to your cPanel, and go to Redirects.

Redirect WWW to non-WWW:

Redirect non-WWW to WWW:

 

Redirect Using IIS7

With IIS7, there are actually two ways to do this. The URL Rewrite extension is required for this.

The first method involves adding the following as the first rule in the system.webServer section of the web.config file of the site in question.

Redirect WWW to non-WWW:

<rewrite>
   <rules>
      <rule name="www to non www"" enabled="true">
         <match url="(.*)" />
         <conditions>
            <add input="{HTTP_HOST}" negate="true" pattern="^www\.yourdomain\.com$"  />
         </conditions>
         <action type="Redirect" url=http://www\.yourdomain\.com/{R:1}” redirectType="Permanent" />
      </rule>
   </rules>
</rewrite>

Redirect non-WWW to WWW:

<rewrite>
   <rules>
      <rule name="non www to www" enabled="true">
         <match url="(.*)" />
         <conditions>
            <add input="{HTTP_HOST}" negate="true" pattern="^www\.youdomain\.com$" />
         </conditions>
         <action type="Redirect" url="http://www\.yourdomain.\com/{R:0}" redirectType="Permanent" />
      </rule>
   </rules>
</rewrite>

The second way is using the user interface of the URL Rewrite module. You can follow the steps outlined on Scott Forsyth’s blog. I suppose you could call that the lazy way to redirect in IIS7.

 

Redirect Using nginx

Nginx is starting to gain popularity due to lower overhead and higher performance than other servers. For the redirect, you will add one of the following to the top of your site’s config file.

Redirect WWW to non-WWW

server {
    listen 80;
    server_name www.yourdomain.com;
    rewrite ^/(.*) http://yourdomain.com/$1 permanent;
}

Redirect non-WWW to WWW

server {
    listen 80;
    server_name yourdomain.com;
    rewrite ^/(.*) http://www.yourdomain.com/$1 permanent;
}

 

Whether you’re on Apache, IIS, or nginx these methods really only take a few minutes to set up, so you really don’t have much of an excuse not to.

Photo: Fabrizio Sciami/Flickr