title: IP over Bluetooth with Raspbian systems
body: <p>I have got 2 Raspberry Pis, running Raspbian, up-to-date. Each Pi has exactly one Bluetooth USB dongle. I can make them communicate via RFCOMM using <a href="http://people.csail.mit.edu/albert/bluez-intro/x232.html" rel="noreferrer">this.</a></p>
  
  <p>Now, I would like to establish a proper IP layer over the Bluetooth physical link. As far as I understand, I have to use PAN (Personal Area Network), that should create a network interface I could manage with ifconfig. I am trying to adapt <a href="http://fedoranews.org/contributors/muhammad_al_ismail/bluetooth/" rel="noreferrer">this tutorial</a>, but I am stuck at an <em>invalid exchange</em> error.</p>
  
  <p>On RPi0, I run</p>
  
  <pre><code>$ sudo pand --nodetach --listen --master --role=NAP
  pand[2313]: Bluetooth PAN daemon version 4.99
  </code></pre>
  
  <p>On RPi1, I run</p>
  
  <pre><code>$ pand --nodetach --connect 00:1A:7D:DA:71:16
  pand[2323]: Bluetooth PAN daemon version 4.99
  pand[2323]: Connecting to 00:1A:7D:DA:71:16
  pand[2323]: Connect to 00:1A:7D:DA:71:16 failed. Invalid exchange(52)
  </code></pre>
  
  <p>I cannot find any relevant information about this error code. Any idea how I could solve this ? Or am I mistaken and should I use something else instead of PAN ?</p>
  
  <p>Thanks in advance !</p>
  
  <p>EDIT:
  When specifying the Bluetooth device I want to listen on, I get another error message. It doesn't really make sense either, since I do not run any other Bluetooth server.</p>
  
  <pre><code>$ sudo pand -i 00:1A:7D:DA:71:16 --nodetach --listen --role=NAP
  pand[2582]: Bluetooth PAN daemon version 4.99
  pand[2582]: Bind failed. Address already in use(98)
  </code></pre>