You could log the IP addresses to a file and then search it. If you're running your site with a database you could log them to a table. 
$address=$ENV{REMOTE_ADDR};
open FILE, "<logaddresses.dat";
my $addresses;
{
local $/=undef;
$addresses=<FILE>;
}
close FILE;
if($addresses=~/\Q$address/){
   print "You already voted\n";
} else{
   open FILE, ">>logaddresses.dat";
   print " $address\n";
   close FILE;
   # update poll;
}
#display results;

[download]
if you want code for a database solution let me know

In reply to RE: Checking user's IP.... by vroom
in thread Checking user's IP.... by Anonymous Monk

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