nameservers) { $config->nameservers[] = '8.8.8.8'; } $factory = new Factory(); $resolver = $factory->create($config); $names = array_slice($argv, 1); if (!$names) { $names = array('google.com', 'www.google.com', 'gmail.com'); } foreach ($names as $name) { $resolver->resolve($name)->then(function ($ip) use ($name) { echo 'IP for ' . $name . ': ' . $ip . PHP_EOL; }, 'printf'); }