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Re: repeated attempts delivering mail to 'unknown user@samedomain'

lars brun nielsen schrieb:

> Feb  6 08:11:27 celery postfix/smtpd[11548]: reject: RCPT from shawidc-mo1.cg.shawcable.net[]: 550 <MULRVNHSVJM@DOMAIN.XX>: User unknown; from=<> to=<MULRVNHSVJM@DOMAIN.XX>

"<>", an empty Return-Path:/Envelope-Sender, so those are bounces /

> an explanation eludes me, [...]

Somebody is spamming while using adresses from your domain as the
faked sender of those spam-mails. That's quite old news for some
years; SPF was invented to avoid that. If you're lucky, you'll get
some hundred of those bounces and be done with; if your're unlucky,
you'll get some hundred *thousand* of them, or even more.


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