Re: RE: [Asrg] 2.a.1 Analysis of Actual Spam Data -Experimental Desi gn

[Brad Knowles <brad.knowles@skynet.be>]

At 2:15 PM +0100 2003/08/19, Jon Kyme wrote:

>  The demand of generating bounces to a spam run (to no doubt forged senders)
>  had crippled their (exchange) server. When asked why they weren't just
>  rejecting unknown recipients they said that Mgmt wanted to see
>  "wrong email addresses".  How we laughed.
	Hmm.  Well, issuing response codes like that immediately to mail 
messages could also be used as a method of determining what are valid 
e-mail accounts.

	Out of curiosity, have you tried the reverse?  Specifically, 
seeing if you get more or less spam sent directly to your valid 
accounts when you do not issue 55x responses to attempts to send 
e-mail to invalid accounts?

>  And then of course there's Yahoo and many others.
	Due to the way the AOL mail system was structured, we had this 
problem as well.  This was resolved once they went to the 
next-generation mail gateway servers that had direct access to the 
back-end system, and could write the message directly through without 
any queueing.

	Of course, then spammers just try to route their effluent through 
the backup MXes, in the hope that they don't check whether or not the 
recipient is valid.  ;(

--
Brad Knowles, <brad.knowles@skynet.be>

"They that can give up essential liberty to obtain a little temporary
safety deserve neither liberty nor safety."
    -Benjamin Franklin, Historical Review of Pennsylvania.

GCS/IT d+(-) s:+(++)>: a C++(+++)$ UMBSHI++++$ P+>++ L+ !E-(---) W+++(--) N+
!w--- O- M++ V PS++(+++) PE- Y+(++) PGP>+++ t+(+++) 5++(+++) X++(+++) R+(+++)
tv+(+++) b+(++++) DI+(++++) D+(++) G+(++++) e++>++++ h--- r---(+++)* z(+++)

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