title: What is the difference between ssh proxycommand -W, nc, exec nc
body: <p>I have seen a few blogs about .ssh/config and <code>proxycommand</code> </p>
  
  <p>now what is the difference between the next commands</p>
  
  <p><code>ProxyCommand ssh proxyserver -W [%h]:%p</code></p>
  
  <p><code>ProxyCommand ssh proxyserver nc -q0 %h %p 2&gt; /dev/null</code></p>
  
  <p><code>ProxyCommand ssh proxyserver exec nc -q0 %h %p 2&gt; /dev/null</code></p>
  
  <p>Some of these commands work on some machines, and don't work on others.</p>