Retransmissão de backscatter do servidor mx de backup do Postfix causando spam (553 5.7.1)

Question

Eu tenho 2 servidores Postfix

• MAIN.mail.example.com
• BACKUP.mail.example.com

Cenário do problema :

1. Se o remetente de spam enviar um e-mail de "eu" para mim diretamente para o BACKUP, o servidor o encaminhará para MAIN

2. O servidor principal rejeita o e-mail com e-mail me envia reject mail said: 553 5.7.1 <[email protected]>: Sender address rejected: not logged in (in replyto RCPT TO command)

Como evitar esse Backscatter? Qual regra e onde posso colocar BACKUP ou MAIN para avisar essas mensagens falsas?

Mensagem RAW

Return-Path: <>
X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on MAIN.mail.example.com
X-Spam-Level: *
X-Spam-Status: No, score=1.8 required=5.0 tests=BAYES_50,RDNS_DYNAMIC,
SPF_HELO_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.1
X-Original-To: [email protected]
Delivered-To: [email protected]
Received: from BACKUP.mail.example.com (IP.eu [IP])
by MAIN.mail.example.com (Postfix) with ESMTPS id 1A62C1800A9
for <[email protected]>; Fri, 12 Oct 2018 16:30:15 +0200 (CEST)
Received: by BACKUP.mail.example.com (Postfix)
id C4DF37D059; Fri, 12 Oct 2018 16:30:14 +0200 (CEST)
Date: Fri, 12 Oct 2018 16:30:14 +0200 (CEST)
From: [email protected] (Mail Delivery System)
Subject: Undelivered Mail Returned to Sender
To: [email protected]
Auto-Submitted: auto-replied
MIME-Version: 1.0
Content-Type: multipart/report; report-type=delivery-status;
boundary="13C687D03F.1539354614/BACKUP.mail.example.com"
Content-Transfer-Encoding: 8bit
Message-Id: <[email protected]>

This is a MIME-encapsulated message.

--13C687D03F.1539354614/BACKUP.mail.example.com
Content-Description: Notification
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 8bit

This is the mail system at host BACKUP.mail.example.com.

I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.

For further assistance, please send mail to postmaster.

If you do so, please include this problem report. You can
delete your own text from the attached returned message.

The mail system

<[email protected]>: host MAIN.mail.example.com[IP] said: 553 5.7.1
<[email protected]>: Sender address rejected: not logged in (in reply to
RCPT TO command)

--13C687D03F.1539354614/BACKUP.mail.example.com
Content-Description: Delivery report
Content-Type: message/delivery-status
Content-Transfer-Encoding: 8bit

Reporting-MTA: dns; BACKUP.mail.example.com
X-Postfix-Queue-ID: 13C687D03F
X-Postfix-Sender: rfc822; [email protected]
Arrival-Date: Fri, 12 Oct 2018 16:30:13 +0200 (CEST)

Final-Recipient: rfc822; [email protected]
Original-Recipient: rfc822;[email protected]
Action: failed
Status: 5.7.1
Remote-MTA: dns; MAIN.mail.example.com
Diagnostic-Code: smtp; 553 5.7.1 <[email protected]>: Sender address rejected:
not logged in

--13C687D03F.1539354614/BACKUP.mail.example.com
Content-Description: Undelivered Message
Content-Type: message/rfc822
Content-Transfer-Encoding: 8bit

Return-Path: <[email protected]>
Received: from tools.wormly.com (tools.wormly.com [96.126.113.160])
by BACKUP.mail.example.com (Postfix) with ESMTPS id 13C687D03F
for <[email protected]>; Fri, 12 Oct 2018 16:30:13 +0200 (CEST)
Date: Fri, 12 Oct 2018 14:30:12 +0000
To: [email protected]
From: Wormly SMTP Test <[email protected]>
Subject: Wormly SMTP Test Message
Message-ID: <[email protected]>
MIME-Version: 1.0
Content-Type: text/plain; charset=iso-8859-1

This message was sent using the Wormly SMTP testing tool by this user:
Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/12.0 Safari/605.1.15



--13C687D03F.1539354614/BACKUP.mail.example.com--

BACKUP.mail.example.com

smtpd_relay_restrictions =
  permit_mynetworks,
  permit_sasl_authenticated,
  reject_unauth_destination