Milter-greylist

manu@... wrote:
> Techwolf <techwolf@...> wrote:
> 
>> 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.
> 
> A regexp should catch it:
> from /^$/
> 

Just be careful not to blacklist based on it.

The RFC's require that you *MUST* accept the null return-path because it's used
for DSN messages.

You can end up in the rfc-ignorant RBL for rejecting all messages with null
return-path's.