Ok guys, here is the problem, I know that exist out there a lots of spider programs that go on your website and open all pages and get your content, or maybe an hacker that wants to get your content he can use this kind of program to get it with no problem.
So how can we stop this thing. I know when those programs go to get the website they open one page after another, maybe have an function that checks the rate the user opens pages, lets say 1 pages / 5 second is an spider, so redirect the user to an page that he have to type an authentication using some image? The point is, what is the best way to stop this without losing also performance and letting others crawlers like google pass those authentication so we can have our website indexed and also block unwanted crawlers.
What you guys say?
http://www.robotstxt.org/robotstxt.html
If you are wanting to up security, you can use an incoming proxy like a barracuda web application firewall but there will always be a performance hit. There may be a more specific answer such as use Drupal with login and permissions/taxonomy to segment what is allowable to anonymous users and what is restricted to authenticated ones but I would need more specific information.