title: reverse ssh tunnel
body: <p>I have an embedded device sitting out in the field, connected through a USB cell stick to the Internet. In order to be able to reach it, I establish a reverse ssh tunnel on port 19996 to my home PC to be able to access it.</p>
  
  <p>Now I re-establish that tunnel every 10min (by cron), to make sure I have pretty much uninterrupted access, even when the provider decides to change my IP.</p>
  
  <p>Now I realized that my process list is full of </p>
  
  <pre><code>"4383 root     ssh -R 19996:localhost:22 -f -N user@host"
  </code></pre>
  
  <p>and netstat is loaded up with connections as well. How can I ensure this doesn't happen? I only need one tunnel open at a time,  not 100s of them.</p>