title: Any small program to receive multicast packets on specified UDP port?
body: <p>I'd like to debug some multicast issues, and I hope to have some small programs/utilities to display incoming multicast packets.</p>
  
  <p>From the sending machine(A), I use Richard Stevens's <code>sock</code> program(provided with his TCP/IP Illustrated book Vol1) to send multicast packets(source port=dest port=7000), like this:</p>
  
  <pre><code>sock -u -b 7000 224.0.0.7 7000
  </code></pre>
  
  <p>On the receiving machine(B), I can capture the very sent packet with Wireshark, however, the same <code>sock</code> command running on B does not report receiving anything.</p>
  
  <p>Then, what program should I use on B to see incoming multicast packets, aside from Wireshark which is overkill. </p>
  
  <p>Linux and Windows programs are both welcome.</p>
  
  <p><img src="https://i.stack.imgur.com/OlATQ.png" alt="enter image description here"></p>