title: check email existence using Delphi with Indy or any other components/tools for Delphi
body: <p>I need to check email accounts whether exists or not, I need to do that using Delphi and Indy (if possible)</p>
  
  <p>I have a windows database for ERP system and I need to make sure that the customer enter valid email into the system so I can send to my customer the quotes they request.</p>
  
  <p>I tried to test on yahoo and google using send commands HELO, MAIL and RCPT but no success.</p>