PART 4: FILTERS
Unfortunately nowadays we have to fight spammers and use our resources to stop this annoying peope from reaching our clients.
I am including clamav (antivirus), spamassassin and razor.
Architecture:
Qmail-smtpd instead of using the qmail-queue is now invoking qmail-scanner-queue who takes care of invoking clamav, spamassassin and also doing some scans on it's own.