/**
    * Fetches the IP address of the current visitor
    *
    * @return    string
    */
    function fetch_ip()
    {
        return $_SERVER['REMOTE_ADDR'];
    }

    /**
    * Fetches an alternate IP address of the current visitor, attempting to detect proxies etc.
    *
    * @return    string
    */
    function fetch_alt_ip()
    {
        $alt_ip = $_SERVER['REMOTE_ADDR'];

        if (isset($_SERVER['HTTP_CLIENT_IP']))
        {
            $alt_ip = $_SERVER['HTTP_CLIENT_IP'];
        }
        else if (isset($_SERVER['HTTP_X_FORWARDED_FOR']) AND preg_match_all('#\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}#s', $_SERVER['HTTP_X_FORWARDED_FOR'], $matches))
        {
            // try to avoid using an internal IP address, its probably a proxy
            $ranges = array(
                '10.0.0.0/8' => array(ip2long('10.0.0.0'), ip2long('10.255.255.255')),
                '127.0.0.0/8' => array(ip2long('127.0.0.0'), ip2long('127.255.255.255')),
                '169.254.0.0/16' => array(ip2long('169.254.0.0'), ip2long('169.254.255.255')),
                '172.16.0.0/12' => array(ip2long('172.16.0.0'), ip2long('172.31.255.255')),
                '192.168.0.0/16' => array(ip2long('192.168.0.0'), ip2long('192.168.255.255')),
            );
            foreach ($matches[0] AS $ip)
            {
                $ip_long = ip2long($ip);
                if ($ip_long === false)
                {
                    continue;
                }

                $private_ip = false;
                foreach ($ranges AS $range)
                {
                    if ($ip_long >= $range[0] AND $ip_long <= $range[1])
                    {
                        $private_ip = true;
                        break;
                    }
                }

                if (!$private_ip)
                {
                    $alt_ip = $ip;
                    break;
                }
            }
        }
        else if (isset($_SERVER['HTTP_FROM']))
        {
            $alt_ip = $_SERVER['HTTP_FROM'];
        }

        return $alt_ip;
    }
}