title: dnspython not updated when changing resolv.conf
body: <p>This snippet works perfect </p>
  
  <pre><code>import dns
  import dns.resolver
  
  default = dns.resolver.get_default_resolver()
  nameserver = default.nameservers[0]
  </code></pre>
  
  <p>except that if I change /etc/resolv.conf by hand and call again get_default_resolver function it doesn't bring me the updated address. I need to restart python console to see the change effect.</p>
  
  <p>What am I missing? Should I do the change to resolv.conf using the same library?</p>
  
  <p>Thanks in advance, </p>