--- email.inc (saved version)
+++ (current document)
@@ -78,7 +78,20 @@
 function _webform_validate_email ($formelement, $name) {
   if (!empty($formelement['#value']) && !valid_email_address($formelement['#value'])) {
     form_set_error($name,t("'%value' is not a valid email address",array('%value' => $formelement['#value'])));
-  }
+  } else {
+		if (preg_match("/^([a-zA-Z0-9])+@([a-zA-Z0-9_-])+(\.[a-zA-Z0-9_-]+)+/", $formelement['#value'])) {
+			// gets domain name
+			list($username,$domain)=split('@',$email);
+			//checks for if MX records in the DNS
+			if (!getmxrr ($domain,$mxhosts)) {
+				$valid = FALSE;
+			}
+			$valid =  TRUE;
+		}
+		if ($valid == FALSE) {
+			form_set_error($name,t("'%value' is not a valid email address",array('%value' => $formelement['#value'])));
+		}
+	}
 }
 
 /**