title: ruby cannot assign requested address
body: <p>I had already created a qt program that listens on a specific port on my server. And it works fine. Now I want to create a simple ruby program to do the same. Right now I just have a simple test server using netcat which establishes a network socket and accepts UDP data (this is Ubuntu server by the way):</p>
  
  <pre><code>$ sudo nc -l 1720
  </code></pre>
  
  <p>Now I am just trying to listen on the port in Ruby:</p>
  
  <pre><code># network.rb
  
  require 'socket'
  
  socket = UDPSocket.new
  socket.bind('64.xxx.xx.xxx', 1720)
  </code></pre>
  
  <p>This right away raises this exception:</p>
  
  <pre><code>network.rb:4:in `bind': Cannot assign requested address - bind(2) (Errno::EADDRNOTAVAIL)
  </code></pre>
  
  <p>WHy is it saying the address is not available? All that is there is a netcat socket. The goal is that I will have UDP data coming in from GPRS devices to that port, and then I will have ruby sitting on my ubuntu server listening for that data, then decoding it, and storing it into a postgresql database.  </p>