title: Reciprocal ping: "Request timed out" and "Destination host unreachable"
body: <p>I use a VPN to connect to the internal network of my university. There is an Ubuntu machine in the university that is used for computational purposes. When I connect to the VPN I can ping every machine except the desired machine.</p>
  <p>By pining the target machine from my computer I get:</p>
  <pre><code>Request timed out.
  </code></pre>
  <p>By pinging my own machine from the target machine I get:</p>
  <pre><code>Destination host unreachable
  </code></pre>
  <p>I can ping every other machine from my machine, and my machine from every other machine without a problem.</p>
  <p>May someone please help me in this issue?</p>