title: Strange behaviour of netcat with UDP
body: <p>I noticed a strange behaviour working with netcat and UDP. I start an instance (instance 1) of netcat that listens on a UDP port:</p>
  
  <pre><code>nc -lu -p 10000
  </code></pre>
  
  <p>So i launch another instance of netcat (instance 2) and try to send datagrams to my process:</p>
  
  <pre><code>nc -u 127.0.0.1 10000
  </code></pre>
  
  <p>I see the datagrams. But if i close instance 2 and relaunch again netcat (instance 3):</p>
  
  <pre><code>nc -u 127.0.0.1 10000
  </code></pre>
  
  <p>i can't see datagrams on instance 1's terminal. Obsiously the operating system assigns a different UDP source port at the instance 3 respect to instance 2 and the problem is there: if i use the same instance'2 source port (example 50000):</p>
  
  <pre><code> nc -u -p 50000 127.0.0.1 10000
  </code></pre>
  
  <p>again the instance 1 of netcat receives the datagrams. UDP is a connection less protocol so, why? Is this a standard netcat behaviour?</p>