бля

<?php

class GoodPeopleChecker {

    const
        GOOD_COOKIE = 'i_am_good',
        GOOD_COOKIE_VALUE = 'yes',
        GOOD_COOKIE_LIFETIME = 2147483647;

    protected
        $is_good = null,
        $ip_addresses;

    public function __construct(array $good_peoples_ip_addresses) {
        foreach ($good_peoples_ip_addresses as $ip_address) {
            $this->ip_addresses[ip2long($ip_address)] = true;
        }
    }

    public function currentUserIsGood() {
        if (null === $this->is_good) {
            $this->is_good = $this->check();
        }
        return $this->is_good;
    }

    protected function check() {
        if (isset($_COOKIE[self::GOOD_COOKIE]) && self::GOOD_COOKIE_VALUE === $_COOKIE[self::GOOD_COOKIE]) {
            return true;
        }
        if (!empty($this->ip_addresses[ip2long($_SERVER['REMOTE_ADDR'])])) {
            $host = isset($_SERVER['HTTP_HOST']) ? '.' . preg_replace('@^www\.@', '', $_SERVER['HTTP_HOST']) : null;
            setcookie(self::GOOD_COOKIE, self::GOOD_COOKIE_VALUE, self::GOOD_COOKIE_LIFETIME, '/', $host);
            return true;
        }
        return false;
    }

}

////////////////////////////////////////////////////////////////

$GoodPeopleChecker = new GoodPeopleChecker(array(
    '127.0.0.1',
    '192.168.0.1',
));

//...

if ($GoodPeopleChecker->currentUserIsGood()) {
    echo 'One I met a boy...';
}