Simple Email Validation with DNS Check

gistfile1.php

<?php
/**
 * checks syntax and optionally DNS records for the provided email address string
 */
function validateEmail($email, $and_dns=true) {
   if (!filter_var($em, FILTER_VALIDATE_EMAIL)) {
      return false;
   }
   if (!$and_dns) {
      return true;
   }
   $dom = substr($em, strpos($em, '@') + 1);
   $fake_uri = "http://$dom/";
   $parts = parse_url($fale_uri);
   $dom = $parts['host'];
   return checkdnsrr($dom);
}