title: Number of UDP padding-bytes
body: <p>I am currently looking at the structure of UDP-packets in a DHCP-setup-scenario and have troubles figuring out the number of padding-bytes that I need at the end of the UDP-packet. </p>
  
  <p>I traced the data using Wireshark and can understand the content of the Ethernet-frame down to the UDP-level. What I fail to understand is how many padding bytes 0x00 are added to the UDP-data.
  In my scenario I have a UDP-length of 0x0134 (=308 Bytes/Octets, given from Wireshark), the last seven octets are just padding (=0x00).
  The Wikipedia-article for UDP (<a href="http://en.wikipedia.org/wiki/User_Datagram_Protocol" rel="nofollow">http://en.wikipedia.org/wiki/User_Datagram_Protocol</a>), paragraph "Checksum Computation" mentions padding with Zero-Octets to make multiple of Two Octets. 
  I initially interpreted this as having multiple of two as my UDP-length. However if that was true then I would not need 7 padding octets but could live with one single padding-octet:
  Here's an equivalent of the end of the trace:</p>
  
  <p>Byte-#....Content<br>
  ...<br>
  299d.......0xF9<br>
  300d.......0x2B<br>
  301d.......0xFF<br>
  302d.......0x00<br>
  => Here I would already have a multiple of 2, however I still get six more padding-bytes.</p>
  
  <p>Can somebody help me understand where these six are coming from?</p>
  
  <p>Cheers,</p>
  
  <p>ye_ol_man</p>