title: What is a reliable method to record votes from anonymous users, without allowing duplicates
body: <p>First of all, I searched as best I could and read all SO questions that seem relevant, but nothing specifically answered this. This is not a duplicate, afaik.</p>
  
  <p>Obviously if anonymous voting on a website is allowed, there is no fool proof way to prevent someone voting more than once.</p>
  
  <p>However, I am wondering if someone with experience can aide me in coming up with a reasonably reliable way of tracking absolutely unique visitors and recording votes against those credentials.</p>
  
  <p>Currently I am ensuring that only one vote per item/session combo is allowed, however this is easily circumvented by restarting browser, changing browsers/computers, or clearing your session data.</p>
  
  <p>Recording against IP seems the next reasonable solution but I wonder if this will get false positives too often (multiple people on same LAN behind a NAT will have same external IP, etc).</p>
  
  <p>Is there a middle ground to be had here or some other method/combination I am overlooking?</p>