Lytheum

Well one thing I noticed is PHP's built-in function "gethostbyaddr()". This will return the host name of a given IP, which generally (from what I've noticed) doesn't change very much even when an IP changes. So what if I used this function in conjunction with "similar_text()", and if host that is trying to vote has greater than a 75% match with a host that has already voted in the past 12 hours, deny them? Would just like to hear some thoughts. Otherwise, will most likely take Crabfinger & Eujut's approach. (Which will restrict a few people from voting, which pains me) P.S. I've googled around to find out how to obtain the mac address, and it seems possible. Although I am sure it is not sent in the browsers HTTP headers, I think there is a work-around. I'll look more into that.

That is definitely an approach that I will keep in mind. It will not completely stop abuse, but it will definitely make it harder to do. Thank you. Anyone else with a solution?

Hello. Currently, I run a voting site where voters are tracked by their IP address and can only vote once every 12 hours. The system works well, except it can be exploited very easily. Visitor's only need to renew their ip to be allowed to vote again. I have captcha in place to prevent bots from doing this, but if someone were dedicated, they could get a lot of free votes. Does anyone have a better way to track such things? Cookies will not work either. It's easier to get around than an IP. Perhaps I'll have to use a language other than PHP? Thanks for your help.