this post was submitted on 26 Apr 2025
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There's a bunch of things wrong in this post. Mainly, you should take a look at DNS SPF records.
That's why it bounces!
An unauthorized sender IP should have their messages dropped, not bounced.
Yes, but then what? Your email provider will kindly let you know, as a courtesy, that the email you sent could not be delivered. Normally, you want this notification. Unfortunately, hotmail, for example, for one, does not determine whether you really sent the email or not. That the FROM: address has you, It will inform you anyway that the email was not delivered. There are no DNS records to stop this.
Nope, they look up the domain dmarc record for the sending domain and add all the dropped records to a aggregated abuse report which is sent as one email to your postmaster.
If the email is not accepted by the receiving imap or pop3 server, it sometimes follows the DMARC instructions for reporting. The report goes to the domain owner of the sending domain. This is done by the receiving server. SPF, DKIM, and DMARC are instructions to the RECEIVING email server, not to the sending email server.
The bounce I'm talking about is from your SMTP server that is following the protocol to let you know, as a courtesy, that your email could not be delivered. And that protocol simply says, in the absence of anything else saying otherwise, tell the FROM: address that their message did not get delivered, even if there is strong evidence that the FROM: address is a fraud.
You keep saying we don't read or we don't understand, but as an email admin at a large company, let me tell you that actually you are wrong.
The sending server doesn't even know whether the spam mail was delivered or dropped by the receiving end.
It only knows in case the mail was rejected.
My mail server has no knowledge of the mails the spammer sent, what are you talking about? This is no open relay.
I'm very sure that, by default, at least postfix will send bounces only to local senders. So unless the spammers use your SMTP server to send spam, you shouldn't get any bounces. If they do, you have different problems.
Tell that to hotmail because they keep sending it. And be sure to update Google too because they don't know as much as you either. https://support.google.com/mail/thread/209018675/my-sent-email-box-is-filling-up-with-bounce-emails-and-emails-i-did-not-send-my-inbox-is-fine?hl=en