title: Simulating host unreachable - how to achieve/implement it
body: <p>Here is my scenario:</p>
  
  <p>A is a provisioning server and B is an client. Whenever there is any change in B's setup, it uploads the appropriate config file to A. </p>
  
  <p>I am working as an automation engineer to automate it. One of the scenario says to disconnect A from network or stop the server A. perform some changes to B and make sure that B failed to upload the files to provisioning server A. </p>
  
  <p>To automate it, the simple way to stop the server A and do the appropriate actions.</p>
  
  <p>Since A and B are also used for other purposes by other parties so I can not either disconnect A or B from network OR stop the server at A. </p>
  
  <p>So, I am looking forward for any solution so that I can simulate the host (provisioning server) unreachable scenario. So when B will send an update to A it will fail but in actual A is running as usual. </p>
  
  <p>Please suggest me some way to achieve it. </p>
  
  <p>I am using Perl as a programming language but I am fine if solution is available in other language.</p>