title: Message-ID header of Yahoo mail
body: <p>Usually the <em>Message-ID</em> header from a specific sender that uses a yahoo email account is like this:</p>
  
  <pre><code>Message-ID: &lt;1415953854.62001.YahooMailNeo@web172504.mail.ir2.yahoo.com&gt;
  </code></pre>
  
  <p>And comes along with the <em>X-Mailer</em> header</p>
  
  <pre><code>X-Mailer: YahooMailWebService/0.8.203.733
  </code></pre>
  
  <p>But sometimes the email headers of the same sender may include a different <em>Message-ID</em> header:</p>
  
  <pre><code>Message-ID: &lt;763084588.2169028.1420389380369.JavaMail.yahoo@jws11101g.mail.ir2.yahoo.com&gt;
  </code></pre>
  
  <p>In which cases there is no <em>X-Mailer</em> header.</p>
  
  <p><a href="http://www.forensicswiki.org/wiki/Yahoo!_Mail_Header_Format" rel="nofollow">Here</a> it says that the <em>Message-ID</em> header of the first case (...<strong>YahooMailNeo</strong>...) indicates it was sent via Yahoo Webmail from Chrome.</p>
  
  <p>So does anybody know which interface does <strong>JavaMail.yahoo</strong> of the second case indicate?</p>