title: How to using telnet to test fix protocol?
body: <p>I am sending a <code>Logon</code> request in telnet:</p>
  
  <pre><code>$ telnet example.com
  Trying example.com...
  Connected to example.com
  Escape character is '^]'.
  8=FIX.4.4 9=103 35=A 49=Q142 56=XCD1 34=221 52=20170929-09:36:39 98=0 108=30 553=primexm_hgnh_uat_1_q 554=tVN84Y93THc5 10=023 
  </code></pre>
  
  <p>Then I try to capture the request in Wireshark:</p>
  
  <p><a href="https://i.stack.imgur.com/N1fwT.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/N1fwT.png" alt="enter image description here"></a></p>
  
  <p>It alert me: <code>the BeginString field is missing</code>, what's the problem when using telnet for test fix protocol</p>