Preventing revotes in a voting system
<p>I have setup a polling system, where when you vote it stores your external IP using:</p>

<pre><code>$_SERVER['REMOTE_ADDR'];
</code></pre>

<p>It stores this in a database called IPlist.
It also sets a cookie.
In the polling page if the cookie is set or the number of mysql_num_rows is greater than 1 it disables the radio boxes.
This is to prevent re-voting.</p>

<p>However some computers have the same external IPs. These can be hundreds at one time like at my school. If I vote on one computer nobody can vote at my school again.</p>

<p>Is there any way to get around this. For example to find the number of computers in the network then change mysql_num_rows. Or to find a unique Constant variable on every computer to store in a database.</p>

<p>Thanks.</p>
