title: How to extract an IPv4 address from a Packet?
body: <p>I have this <code>byte[]</code> that represent <code>IPv4 packet</code>:</p>
  
  <pre><code>byte[] arr = { 0, 48, 136, 21, 69, 131, 0, 24, 231, 253, 174, 161, 8, 0, 69, 0, 0, 52, 2, 31, 64, 0, 128, 6, 230, 22, 212, 25, 99, 74, 202, 177, 16, 121, 194, 156, 0, 119, 160, 128, 75, 200, 249, 141, 210, 78, 80, 24, 64, 252, 130, 182, 0, 0, 65, 82, 84, 73, 67, 76, 69, 32, 51, 52, 13, 10 };
  </code></pre>
  
  <p>And i want to calculate the <code>IPV4 address</code></p>