[Info-vax] inhibit email with From: <> from being sent

[Phillip Helbig---undress to reply]

In article <9m3ce5F3gnU2 at mid.individual.net>, Bob Eager
<news0001 at eager.cx> writes: 

> > In the log of my SMTP relay server, I occasionally see a record of
> > emails sent from the adress "<>", i.e. with an empty From: header.  I
> > suspect this is some sort of backscatter spam.  (In general, a
> > combination of RBL and setting Symbiont-Checks-Deliverability: to FALSE
> > has stopped most of my spam.)  Is there any way to prevent this from
> > being sent?
> 
> No, it's a valid thing to do. Read RFC 5321, section 4.5.5 in particular.
> 
> It is not backscatter spam - in fact, it's almost the opposite.

I had a quick glance: delivery-status notification or something like 
that.  But the address is not one I recognize (I have NEVER noticed such 
an email getting sent to an address I recognize), so I am assuming that 
while perhaps it SHOULD be generated, maybe someone sent a spam email to 
a non-existent user (with more than 12 characters, so that my old 
version of SMTP doesn't just drop it) and this is the automatic response 
to that.  But suppose the From: address is bogus; in that case it would 
be backscatter spam, right?