Is it possible to disable the postfix notification "Undelivered Mail Returned to Sender"?

Since I receive too much spam with forged senders, I don't want postfix to notify these forged senders.


If you make postfix just reject the mail as it comes in, it doesn't use the sender address, it just refuses the email at the "RCPT TO" stage. Make sure you have

unknown_local_recipient_reject_code = 550

I'm not sure what else you've got going on, but at least on my postfix, if somebody attempts to send an email to an unknown local user, it gets bounced early in the connection rather than after they've connected and sent you the message.

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The question is why your MTA accepts mails to non-existent recipients in the first place. It should just finish the SMTP dialog with the connecting (Spam-) client with a permanent error (5xx) message. You should really have a good reason disabling DSNs (delivery status notifications).

See smtpd_recipient_restrictions or more precisely the restriction reject_unverified_recipient in the Postfix manual. You should also read the Postfix Address Verification Howto.

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  • The OP said "forged senders", not "forged recipients". Any reason why you understood otherwise? – ΤΖΩΤΖΙΟΥ Oct 29 '09 at 0:25
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    When Postfix (or generally any MTA) generates a DSN (the "Undelivered Mail Returned to Sender" mail) it means that something went wrong with delivering the mail. Usually that's because the recipient was invalid or anything else went severely wrong. If this is the case, the MTA could as well generate a 5xx status during the SMTP dialogue and not accept the mail in the first place. So instead of treating the symptoms (sending out DSNs) I described how to treat the possible cause. – joschi Oct 29 '09 at 10:57

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