RewriteEngine On
RewriteCond %{HTTP_REFERER}!^http://a166.com/.*$ [NC]
RewriteCond %{HTTP_REFERER}!^http://a166.com$ [NC]
RewriteCond %{HTTP_REFERER}!^http://www.a166.com/.*$ [NC]
RewriteCond %{HTTP_REFERER}!^http://www.a166.com$ [NC]
RewriteRule .*.(gif|jpg|jpeg|png|bmp|swf|mp3|wav|zip|rar)$ http://www.bignethk.com/404.html [R,NC]