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What to do when we have several domain names pointing to the same site to handle best the referencing ?

Be it to protect the closest names (ex: mysite.com and my-site.com) or to take advantage of the various TLD (Top Level Domain) (ex: mysite.com and mysite.org), there are good reasons to use several domain names for a single site.

If we don’t pay attention, the search engines that matter (exhaustive list of search engines that matter:Google) can see those sites as duplicates and/or arbitrarily attribute the pages to one domain or another , diluting your results in the SERP (Search Engine Result Pages). In any case, the quality of your referencing suffers.

To avoid this problem, we have to choose a main domain name that will be used as a reference. This implies using that name everywhere you may need to write a URL, and also to alter the behaviour of the secondary domains.

We’ll make the secondary domains return the same content as the main domain, while warning the robots they’re not on the main domain. Once again, the HTTP error codes will get useful : we will return a 301 code (moved permanently) along with the content.

Note that a 302 error code (moved temporarily) would be way less efficient about what we’re trying to achieve… and that’s the one that gets sent by default when a redirection occurs !

To return that code, several methods exist. The simplest is probably the use of the ‘redirect’ instruction in the web server (Apache) configuration or in a .htaccess file at the server root.

Here is the instruction to use to redirect all requests to the main address :

Redirect 301 / http://mysite.com/

or

Redirect permanent / http://mysite.com/

You could for example include a virtual hostname for every secondary domain this way :

<VirtualHost *:80>
    ServerName www.mysite.org
    ServerAlias mysite.org
    ServerAlias www.my-site.com
    ServerAlias my-site.com
    <IfModule mod_alias.c>
        Redirect permanent / http://www.my-main-site.com/
    </IfModule>
</VirtualHost>

Another way of achieving this without altering Apache’s conf would be to apply RewriteRules through a .htaccess file at the root of your site. For example :

RewriteEngine On
RewriteCond %{HTTP_HOST} ^(.*)my-site.com$
RewriteRule ^(.*)$ http://www.my-main-site.com/$1 [R=301,L]

or with :

RedirectMatch 301 /blog(.*) /$1

With a well handled error code, you make sure the main domain achieves all its potential. The search engines that matter are happy, so are you !