Redirect issue

Why does www.domain.com redirect to domain.com in Dolphin 7.1? I looked at .htaccess but did not find this. When I modify .htaccess to redirect domain.com to www.domain.com, I end up with redirect loops. Can someone please tell me how to fix this?

Thanks.

You may want to check your /inc/header.inc.php under the $site['url'] setting.