Milter-greylist

Hi all.

I just got flooded with a lot of mail to some domains. All the mail got though 
greylist due to non-listed rbl ips. However, I did notice all the mail 
had "from=<>" in the sendmail logs. Is there a way to acl a rule to detect an 
empty from field? The docs don't show an example or explain how to detect an 
empty field.

Also, all the mail was random to: addresses. One poor user had a wildcarded 
domain and got over a 1000 spams in a day.

Oh, version milter-greylist-3.1.6-1

--Techwolf