Index: lib/ezutils/classes/ezsmtptransport.php
===================================================================
--- lib/ezutils/classes/ezsmtptransport.php	(revision 24228)
+++ lib/ezutils/classes/ezsmtptransport.php	(working copy)
@@ -96,7 +96,7 @@
             $sendData['CcRecipients'] = $mail->ccReceiverTextList();
             $sendData['BccRecipients'] = $mail->bccReceiverTextList();
         }
-        $sendData['headers'] = $mail->headerTextList();
+        $sendData['headers'] = $mail->headerTextList( array( 'exclude-headers' => $ini->variable( 'MailSettings', 'ExcludeHeaders' ) ) );
         $sendData['body'] = $mail->body();
 
         $smtp = new smtp( $parameters );
Index: settings/site.ini
===================================================================
--- settings/site.ini	(revision 24228)
+++ settings/site.ini	(working copy)
@@ -1036,6 +1036,9 @@
 DebugSending=disabled
 # Receiver email address to use when DebugSending is enabled
 DebugReceiverEmail=
+# Headers to exclude from the sent message, case insensitive, only relevant when using SMTP
+# You might want to add bcc here, if your mail server does not hide bcc recipients from each other
+ExcludeHeaders[]
 
 [ShopSettings]
 # This settings controls when the basket is cleared.