Hi, I have a website. It is built by apache + tomcat. Now we make a lottery activity at this website. But we find that some robots always raise the duplicated requests to hit this lottery activity. It causes that robots almost get all the awards. So we just want to block these kind of duplicated requests at every interval unit. For example, we set the interval unit is 3 seconds. The if the robot want to hit the lottery activity in 3 seconds, the website could block this action. So how to do it? I suppose if we do it at tomcat level, is it a very low performance? Can I do it at apache level? how to do it? If I could not do it apache level? Thanks in advance, Java Coder