title: iperf can't connect from remote machine
body: <p>I am trying to measure the network bandwidth between two cloud virtual machines, using iperf. Machine A runs </p>
  
  <pre><code>    iperf -s 
  </code></pre>
  
  <p>and machine B </p>
  
  <pre><code>    iperf -c &lt;ip of machine A&gt;.
  </code></pre>
  
  <p>This doesn't work, while executing </p>
  
  <pre><code>    iperf -c localhost 
  </code></pre>
  
  <p>in machine A works fine. The firewall is not the problem as I have opened the port needed(5001 , using sudo ufw allow 5001). </p>
  
  <p>Also, I would like to note that the whole process works flawlessly on machines running on another cloud provider.</p>