title: difference between SSH -X and ssh -Y
body: <p>I was SSH'ing into a server by running a code like this:</p>
  
  <pre><code>ssh serverUser@serverIP "./runServer" &amp;
  </code></pre>
  
  <p>on the very next line of the script when I started a VM at the client and wrote startX on it, it said: <code>X Error of failed request: Bad Window.</code></p>
  
  <p>After looking up this error, I resolved this by sshing using the 'Y' forwarding.</p>
  
  <pre><code>ssh -Y serverUser@serverIP "./runServer" &amp;
  </code></pre>
  
  <p>I am unable to understand if X and Y forwarding are the same concepts -  and how many such X, Y Z forwardings are possible?</p>
  
  <p>Thanks.</p>