title: Address family not supported by protocol family
body: <p>I tried to do the ruby example shown in this page: <a href="http://tomayko.com/writings/unicorn-is-unix" rel="noreferrer">http://tomayko.com/writings/unicorn-is-unix</a></p>
  
  <p>but all I got was</p>
  
  <pre><code>echo.rb:9:in `bind': Address family not supported by protocol family - bind(2) (Errno::EAFNOSUPPORT)
      from echo.rb:9:in `&lt;main&gt;'
  </code></pre>
  
  <p>Any idea?</p>