I think it would be valuable to write all IPs to a file. Have a space separating the IP from the USER_AGENT on each line. Then suck each line into a regex like /(\S+)\s(.*)/ so that $1 has the IP and $2 is the rest of the info you'd want to store about each session. Make a hash $visitlog{$1}=$2 for each line. When you get a new submission, check
if (defined $visitlog{$newipadd}) {
# maybe check $USER_AGENT && $othrsave stuff to examine
# if anything further about unique proxy users can be determined
#failure code && error mesg
} else {
# maybe check $USER_AGENT && $othrsave stuff to further
# determine if the user is attempting to revote.
#process vote && success mesg
$visitlog{$newipadd} = "$USER_AGENT" . $othrsave;
}
Then before you end the script, overwrite your logfile with the current visitlog hash with each line containing "$key $value". This is how I'd probably do it. Hope it's helpful. I'd be glad to try to help more if you'd like any. TTFN & Shalom.
-PipTigger