.htaccess remove www.

Setting up a multisite to use subdomains says it is better to remove the www. prefix.

I have tried adding this to my .htaccess but it gives me a redirect error message on the page.

Please can someone tell me what I have done wrong? the added lines in bold.

SetEnv DEFAULT_PHP_VERSION 53

DirectoryIndex index.cgi index.php

# BEGIN WordPress

<IfModule mod_rewrite.c>

RewriteEngine On

RewriteBase /

RewriteRule ^index.php$ – [L]

RewriteCond %{REQUEST_FILENAME} !-f

RewriteCond %{REQUEST_FILENAME} !-d

RewriteRule . /index.php [L]

RewriteCond %{HTTP_HOST} ^www.closefocus.net [NC]

RewriteRule ^(.*)$ http://closefocus.net/$1 [L,R=301]

</IfModule>

# END WordPress