国产浏览器屏蔽网站是什么原理？

[img]http://img.nga.178.com/attachments/mon_201209/14/-47218_5052bc4cc6331.png[/img][img]http://img.nga.178.com/attachments/mon_201209/14/-47218_5052bc4cc6331.png[/img][img]http://img.nga.178.com/attachments/mon_201209/14/-47218_5052bc4cc6331.png[/img]我记得996icu被屏蔽了。