[Mimedefang] New spam technique

WBrown at e1b.org WBrown at e1b.org
Tue Jul 6 10:02:04 EDT 2004


mimedefang-bounces at lists.roaringpenguin.com wrote on 07/05/2004 02:27:49 
PM:

> That doesn't work if there is more than one recipient, some valid and 
some
> invalid.  At the end of DATA, you can only indicate success or failure 
for
> the entire message and all recipients.
> 
> Exchange does this by default; it's forced to generate NDN's for invalid
> recipients.
> 
> Really, there needs to be an extension to SMTP that lets you return
> multiple success/failure codes after DATA (one code per recipient).

But if you return a code at the end that says baduser at domain.com is 
invalid, but gooduser at domain.com is valid, have you really changed 
anything from when you failed it after RCPT TO? It doesn't seem that way. 
The spammers still know which addresses got through, and which ones were 
rejected and they can still clean their lists.



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