[TYPO3-dev] Fatal error: Class '...\Controller\Net_DNS_Resolver' not foun

[Roman Pretory]

Hello

I try to rebuild a ext in Typo3 7.6.

I have to use folowing in the Controller:
		require_once 'Net/DNS.php';
 			$resolver = new Net_DNS_Resolver();
 			$resolver->tcp_timeout = '10';
			$response = $resolver->rawQuery($conf['domain'], 'NS');

And get this as error:
Fatal error: Class '......\Controller\Net_DNS_Resolver' not found in ..../Classes/Controller/CheckdnsController.php on line 343

Why??

Thanks RP