/**
  * Exists
  *
  * Uses SMTP/MX Query Requests to check whether or not the Email
  * address exists on the server.
  *
  * **This requires an active, open net connection**
  * **This could fail if your outbound IP/mail server has been blacklisted**
  *
  * @param string $email Email address to discover
  * @return Returns TRUE if the server response verifies the Email address.
  * FALSE otherwise.
  */
 public static function exists($email)
 {
     if (!EmailValidator::validate($email)) {
         return false;
     }
     $smtp = new SmtpLookup\SmtpLookup();
     return $smtp->lookup($email);
 }
<?php

require __DIR__ . '/../SmtpLookup/SmtpLookup.class.php';
use EmailValidator\SmtpLookup;
$email = '*****@*****.**';
$smtp = new SmtpLookup\SmtpLookup();
var_dump($smtp->lookup($email));