title: How to read ip address of the incoming emails
body: <p>I have set a continuous project for my class which is available online for students and parents can interact with. So I ask students to email their project progress everyday. I use imap to get the info and display it online. </p>
  
  <p>I understand email addresses can be spoofed. How can I find out if the mail really did come from yahoo, gmail or hotmail. Which imap function could i use. i tried this</p>
  
  <blockquote>
    <p>imap_headerinfo($inbox, $emails[$x])</p>
  </blockquote>
  
  <p>But It does not give me ip address of the servers it passed through.</p>
  
  <p>I appreciate any help. </p>