title: Mosquitto TLS, works with MQTTfx but not mosquitto_pub (tlsv1 alert unknown ca)
body: <p>Quite strange issue</p>
  
  <p>I have mosquitto broker working with TLS</p>
  
  <p>It is correctly accessible by an MQTTfx client set up for 'Enable SSL/TLS, TLSv1.2, CA certificate file'</p>
  
  <p>The same ca.crt file is used by a openwrt mosquitto client issuing</p>
  
  <pre><code> # mosquitto_pub -h x.x.x.x -p 8883 --cafile /etc/mosquitto/certs/ca.crt -i 1.1.1.1 -t test -m 123 -d
  </code></pre>
  
  <p>it returns</p>
  
  <pre><code>Client 1.1.1.1 sending CONNECT
  Error: A TLS error occurred.
  </code></pre>
  
  <p>At the orher end, the broker, shows</p>
  
  <pre><code>OpenSSL Error: error:14094418:SSL routines:SSL3_READ_BYTES:tlsv1 alert unknown ca
  OpenSSL Error: error:140940E5:SSL routines:SSL3_READ_BYTES:ssl handshake failure
  Socket error on client (null), disconnecting.
  </code></pre>
  
  <p>What is messing me up is the fact that the MQTTfx client instead is accepted, and it's using the same certificate..!</p>
  
  <pre><code>New connection from y.y.y.y on port 8883.
  New client connected from y.y.y.y as 180ce1c04c1944e1964608221efbcf0a (c1, k60).
  Sending CONNACK to 180ce1c04c1944e1964608221efbcf0a (0)
  </code></pre>
  
  <p>Should mean that the certificate is valid and trusted... isn't it?
  What's wrong then with the other client using the exact same certificate file ?!?!</p>