Email ???

[Ed Greshko]

On average, for one domain that I manage, we get 2500~3000 incoming
connections/day.

I use smf-grey, smf-spamd, RBL, and I permanently reject all incoming mails
that are not valid recipients in the domain.

About 10% of the incoming mails are delivered the remaining 90% are
rejected.  Of the delivered messages, less than 0.8% are spam.

All strategies for fighting spam have their advantages and disadvantages.
It is not, IMHO, a good idea to rely on a single defense.

I'm happy with my setup.  And, I've no complaints from the user community.