Avoid duplicate content

As experimented webmaster you know that duplicate content is very bad for your ranking. You are very cautious to avoid to have the same content duplicate on differents pages. But are you sure that your pages are really unique? If you didn't pay attention, you can have all your pages with two different url: www.example.com/page.htm and example.com/page.htm. For your home page it can be up to four different url !!! Don't panic, there is easy solutions to avoid that.

To avoid duplicate content between www.example.com and example.com; we will force the usage of www.example.com with an .htaccess file to install at the root of your hosting with the following content:

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

You will have to replace example.com with the url of your site. If there is already an .htaccess file in place, just copy the lines inside the existing file.

For the home page to avoid duplicate content between www.example.com et www.example.com/index.php; we will force the www.example.com url with a small php code to put at the beginning of the page index.php:

$url = $_SERVER["REQUEST_URI"];
if($url=='/index.php')
{
header("HTTP/1.1 301 Moved Permanently");
header("Location: http://".$_SERVER['HTTP_HOST']."/");
}