title: Can we know that the visit is from the file such as /etc/hosts
body: <p>when i visit the github.com,and then get a tip like that:</p>
  
  <blockquote>
    <p>You have a stale /etc/hosts entry for GitHub.com. Please remove that
    entry ASAP!</p>
  </blockquote>
  
  <p>And it confused me, as you can see below:</p>
  
  <blockquote>
    <ol>
    <li><p>Can we get the visit source come form the hosts file and how it works?</p></li>
    <li><p>If the answer is NO, i guess that the github.com know it because of the request ip is old, and then the website display the tip.</p></li>
    </ol>
  </blockquote>
  
  <p>Sure the /etc/hosts file had been edited. I am in the CHINA, you know.</p>
  
  <p>And thanks to look at this question.</p>