Blank emails

[Peter Bishop]

Sadly, it would appear that my suspicions about blank emails have 
been confirmed.

Soon after getting the blanks, my typical spams per day jumped from
around 70 /per day to around 150 /day !!

So it looks like blank emails *are* being used to authenticate 
addresses for spam mailing lists.

On the other hand this problem could be viewed as an opportunity to 
get yourself off mailing lists if we can recognise such probes and 
send a rejection 

Chris Fortume advised  that the MTA should answer to empty emails:  
"550 user not found" after the DATA command
(ok by RFC2821). 

However I am not an MTA expert
How would that be done using postfix?
-- 
Peter Bishop 
pgb at adelard.com
pgb at csr.city.ac.uk