Neos\Flow\Http\Component\TrustedProxiesComponent::getTrustedClientIpAddress PHP Method

    protected function getTrustedClientIpAddress(Request $request)
    {
        $server = $request->getServerParams();
        if (!isset($server['REMOTE_ADDR'])) {
            return false;
        }
        $ipAddress = $server['REMOTE_ADDR'];
        $trustedIpHeaders = $this->getTrustedProxyHeaderValues(self::HEADER_CLIENT_IP, $request);
        $trustedIpHeader = [];
        while ($trustedIpHeaders->valid()) {
            $trustedIpHeader = $trustedIpHeaders->current();
            if ($trustedIpHeader === null || $this->settings['proxies'] === []) {
                return $server['REMOTE_ADDR'];
            }
            $ipAddress = reset($trustedIpHeader);
            if (filter_var($ipAddress, FILTER_VALIDATE_IP, FILTER_FLAG_NO_RES_RANGE | FILTER_FLAG_NO_PRIV_RANGE) !== false) {
                break;
            }
            $trustedIpHeaders->next();
        }
        if ($this->settings['proxies'] === '*') {
            return $ipAddress;
        }
        $ipAddress = false;
        foreach (array_reverse($trustedIpHeader) as $headerIpAddress) {
            $portPosition = strpos($headerIpAddress, ':');
            $ipAddress = $portPosition !== false ? substr($headerIpAddress, 0, $portPosition) : $headerIpAddress;
            if (!$this->ipIsTrustedProxy($ipAddress)) {
                break;
            }
        }
        return $ipAddress;
    }