title: Detecting when a device has changed physical ethernet port
body: <p>My code is running on a server with multiple Ethernet ports which are physically wired to specific physical locations. Devices with known IPs are plugged in the other ends. I want to be able to detect if a device has changed place (in order to warn/scold the user). I.e, the difference between this:</p>
  
  <pre><code>Port X (192.168.33.1) ------------------ Device A (192.168.33.12)
  Port Y (192.168.33.2) ------------------ Device B (192.168.33.13)
  </code></pre>
  
  <p>and this:</p>
  
  <pre><code>Port X (192.168.33.1) ------------------ Device B (192.168.33.13)
  Port Y (192.168.33.2) ------------------ Device A (192.168.33.12)
  </code></pre>
  
  <p>I've considered putting the devices/ports on different subnets, but I would <em>prefer</em> to be able to say "you need to move device C to position N", rather than "I can't see anything!".</p>
  
  <p><em>Disclaimer: I am not a networking expert</em></p>