So, having fixed the mailflow yesterday, and done the following things:

  • set up greylisting on the primary MX

  • set up greylisting on the secondary MX

  • configured sendmail to bounce the two top fake addresses that spammers use when faking my domain

...today's spam count in my inbox is 1. One spam. No bounces, or challenge-responses, or postmasters, or what have you.

I just checked in my gmail "spam" folder, and there are only two messages there, one of which I put there because we no longer do business with the store that sent this message.

While I am sure that things will get worse again, I'm pretty pleased that I've been able to make things a bit better so simply.