[SOLVED] Stop all (Undelivered Mail Returned to Sender)

[kez]

Hi there,

I'm getting so many bouncebacks like this, please can you get me to stop receiving these? or better, for PMG to stop sending the mail that bounced in the first instance?

In this example, the email bounced from (User unknown).

I already have done the following:

Configuration > Mail Proxy > Options > Send NDR for blocked emails > NO
Configuration > Mail Proxy > Options > Verify Receivers > YES (550)

But to my Configuration > Options > Administrator Email address I still receive all the bounce backs:

MAILER-DAEMON@my-pmg.servers

This is the mail system at host my-pmg.servers

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.

<ugbdvydkxr@au.com>: host mx01.au.com[27.86.106.68] said: 550
   <ugbdvydkxr@au.com>: User unknown (in reply to RCPT TO command)
Reporting-MTA: dns; my-pmg.servers
X-my-pmg.servers-ID: 5831718125B
X-my-pmg.servers-Sender: rfc822; SRS0=5e1d=f=my-pmg.servers=postmaster@davidzema.com
Arrival-Date: Fri, 14 Apr 2023 02:53:27 +0100 (BST)

Final-Recipient: rfc822; ugbdvydkxr@au.com
Original-Recipient: rfc822;ugbdvydkxr@au.com
Action: failed
Status: 5.0.0
Remote-MTA: dns; mx01.au.com
Diagnostic-Code: smtp; 550 <ugbdvydkxr@au.com>: User unknown

Matching Rule: Block outgoing Spam

From: my-pmg.servers
Subject: Notification: 【au PAY】お支払い金額確定のご案内
Date: 14 April 2023 at 02:53:26 BST
To: SRS0=0100=f=au.com=ugbdvydkxr@davidzema.com

 

[dcsapak]

can you post the rule 'block outgoing spam' ? did you maybe add a notification/bcc action there that cannot be sent?

 

[kez]

Hi, Yes there is a Notify Sender rule here. Thank you!

If I enable (Configuration > Mail Proxy > Options > Reject Unknown Senders > YES) would that allow the 'block outgoing spam - Notify Sender rule' to still work for real senders and stop the fake ones?

Ideally, the sender should be notified if their mail is blocked.

 

[dcsapak]

If I enable (Configuration > Mail Proxy > Options > Reject Unknown Senders > YES) would that allow the 'block outgoing spam - Notify Sender rule' to still work for real senders and stop the fake ones?

the rule will work independently of that option, but make sure you understand what that option does exactly:

https://www.postfix.org/postconf.5.html#reject_unknown_sender_domain