title: what is H.225,h.245 and iax2 message format?Want to do signature analysis but my packets are encrypted
body: <p>I am trying to do signature analysis, but all pcap files of h225,h245 and iax2 are encrypted and on net I have not found anything that can help me for getting their signatures. I want to get something like</p>
  
  <pre><code>DESCRIBE rtsp://tmlab-share2/WMLoad.asf RTSP/1.0
  User-Agent: WMPlayer/9.0.0.3060
  Accept: application/sdp
  Accept-Charset: UTF-8, *;q=0.1
  X-Accept-Authentication: Negotiate, NTLM, Digest, Basic
  Accept-Language: en-US, *;q=0.1
  </code></pre>
  
  <p>But I have found nothing like this that can tell me some specific strings.</p>
  
  <p>I just want to know something that can be used in signature. I saw some signatures on net <a href="http://l7-filter.sourceforge.net/layer7-protocols/protocols/h323.pat" rel="nofollow noreferrer">here</a> but these are for Linux's Netfilter subsystem, and these are not working for me. </p>