I'm using the thumb rating system instead of the stars. However there are no restriction settings available for thumbs, only for stars. I found a forum post saying that the restriction settings are copied from stars to thumbs though.
My problem is that some star settings do work for thumbs as well, like 'Prevent article author to vote' and 'Use cookies to prevent duplicate voting', but I cannot restrict users to only vote one time per IP. The IP's are getting logged, but duplicate votes are possible.
I'm using the RPX plugin to let users login my site using openid, facebook, linkedin and twitter. Now if a user logs in with all these sites, they can vote 4 times.
How to prevent this?
PS. I tried registering for the gdragon forum, but the activation mails are never sent.