nameservers ? reset($config->nameservers) : '8.8.8.8'; $factory = new Factory(); $resolver = $factory->create($server, $loop); $name = isset($argv[1]) ? $argv[1] : 'www.google.com'; $resolver->resolve($name)->then(function ($ip) use ($name) { echo 'IP for ' . $name . ': ' . $ip . PHP_EOL; }, 'printf'); $loop->run();