Recently, I found some sites unavailable from China. The site is legal for both China and U.S. and most of them are e-commerce site. When I try to browse them, I've got the following info like below,
Access Denied
You don't have permission to access "http://www.XXXXXX.com/" on this server.
Reference #18.17e0fc7d.1388995628.878368c
I am wondering why they block chinese visitors? and further, by which method they achieve this.