title: nslookup reported "can't resolve '(null)': Name does not resolve" though it successfully resolved the DNS names
body: <p>I am on ubuntu, and I am running a docker default bridge network. I have containerized versions of zookeeper, kafka, and an app that I wrote that talks to kafka. </p>
  
  <p>I do a:</p>
  
  <pre><code>docker exec -it &lt;my-app id&gt; /bin/bash
  </code></pre>
  
  <p>Then inside my app's container I run <code>nslookup kafka</code></p>
  
  <pre><code>/go # nslookup schmafka
  nslookup: can't resolve '(null)': Name does not resolve
  
  Name:      schmafka
  Address 1: 172.20.0.8 docker_kafka_1.docker_default
  </code></pre>
  
  <p>I do not understand why I get the output "can't resolve '(null)'" and then I get the expected ip address printed out later. I tried to google nslookup and this output message but I cannot figure why this happens.</p>
  
  <p>My /etc/resolv.conf file looks like this:</p>
  
  <pre><code>/go # cat /etc/resolv.conf 
  search valhalla.local valhalla v
  nameserver 127.0.0.11
  options ndots:0
  </code></pre>