[eluser]nevsie[/eluser]
not 100% sure what you mean:
Quote:since IP’s changed
Do you mean since people do not always have a fixed IP address? Therefore, if they turn off their router and connect again with a different IP they could always vote again! And if another person came along and happened to have an Old IP from someone else who voted they cannot vote?
I am also not sure on your rating system, how long each rating period runs for, are they rating one thing or multiple? Are these people general public or register members?
Anyway... some ideas...
Use IP and other information such as browser type, number?
Take an email address when the rate something, use that as verification? You could always make sure they authorise the vote through sending an email out as well... This will not stop people with multiple email accounts, but stops fake email addresses.
Only allow members to vote - log their vote against their account with you...
etc. options endless really! but membership is the most logical i guess.