Analysis on the principle of preventing repetitive brush-counting in PHP

The first is to use the verification code, others manually brush the ticket, or even the site to spend hundreds of of dollars to buy a verification code recognition program
Limit IP address, unplug the network cable on the IP, Taobao 2 dollars can buy an IP automatic converter, automatic dial-up Internet
Cookies Just clean it up, okay?
Session When the page closes, it breaks.
MAC address? In Device Manager you can change
User hard drive serial number? Using Software to cheat
Registered users can vote? Unless you have a lot of registered users
Impossible to guard against ...

Recommended ip+ Verification Code +session

Captcha can make some fun.

Netizen Two

The following are the methods I used in a polling website, but I still get mad brushes

Verification code (do not know how his ticket machine to break through this clearance)
Session validation (also not known)
Generate a random number
IP authentication (can be disguised)
Voting sources (can be disguised)

Verification code to get a Chinese, or random number, let's do the calculation, and so on, so you should be able to prevent the machine, the machine can not withstand that is your code has a problem

Final Summary:

Brush ticket problems have always existed, only possible to reduce the way to brush the ticket, you really do not let others brush is impossible, even if the registration, people can register n number! You think that even a real vote would have pulled the ballot. To do not let others brush the ticket, only you control the voting crowd!