swamped by email to non-existent users

I have a domain name that is a common surname.

Sometimes my server gets overwhelmed with emails with just tons of different non-existent users being sent spam.

Right now, emails hit the greylisting program first, and they get turned away. But sometimes they get sent again, and again, and the greylist program finally lets them through and then they get turned away as unknown users and often they get resent again before long, anyway.

Is there a way to set up a filter even before it hits the greylist - a firewall perhaps, so that I can make a list of acceptable addresses, and if it isn’t one of those, it’s bounced away with as minimal of an impact as possible?

Thanks for any ideas on this,


I should mention I am using the gpl version of virtualmin.

Hmm, if they’re destined for a user that doesn’t exist – they should be bounced pretty early in the process.

They would have to go through greylisting first, but once they’re past that, Postfix should reject them prior to the message body even being given to Postfix.

If that’s not the behavior you’re seeing – some pretty strange stuff can occur when dealing with catch-all addresses… is it possible that the messages are being accepted due to a catch-all, and bounced later for some reason?