Asagidaki arkadas derki dos attagin php ile bir alakasi yoktur. Bunu engellemenin en iyi yolu apache module mod_dosevasive yi kurmaktir diyor.

Insallah isine yarar.

http://forums.devshed.com/security-a...ck-300497.html
A good way to prevent a DOS attack and future DOS attackes would be to install the apache module mod_dosevasive. This apache module will help protect against people sending too many requests to the webserver in an attempt to flood it. If it detects too many connections the offending ip will be blocked from the accessing apache for This is especially useful when the server is continuously getting attacked.