How to stop proxy attacks?

[eluser]Dainius123[/eluser]
Hello, I need to stop proxy users from being able to vote in my site. It is a contest and some users use proxies to cheat on voting results.

What methods do you use to stop proxies?
Any ideas?

Thanks for help,


Dainius

[eluser]InsiteFX[/eluser]
PHP Code to Check if Someone is Coming from a Open Proxy

[eluser]Dainius123[/eluser]
But if i will use this function on vote button press then i can possibly get internal server error (if 200 or more users will click) or not? does this function overload server?

Thanks for help,


Dainius