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Re: [Asrg] Unique innovations made to anti-spam system

2006-01-22 13:36:03
On 22nd January 2006 at 21:07, Peter J. Holzer wrote:
On 2006-01-22 19:40:09 -0000, John Levine wrote:
I'm in no way a C/R supporter, but I have done some experiments with C/R
in that past. One "enhancement" I quickly discovered was using VERP
tagging on the challenges, and dropping messages from the pending queue
when the challenge bounced. This cut the pending queue by more then 90%.

Russ Nelson has experimented with a R (no C) technique based on this
observation.  When a message from an unfamiliar address arrives, his
setup sends an auto-ack and puts the mail into a holding pen.  If the
auto-ack bounces, he moves the message into the spam folder.  If after
15 minutes or so there's no bounce, the message moves into the inbox.

He said it works quite well.

However, it still sends mails to innocent bystanders. It is mitigated by
the fact that each address only gets one mail, but if this is widely
implemented, the owners of the forged sender addresses used by spammers
will be bombarded with auto-ack messages.

That would depend if the auto-ack is an entire message, DATA and all, or 
whether it stops after checking the response code to RCPT TO at the sender's 
mailserver.

-- Michael "Soruk" McConnell
   Eridani Star System

   MailStripper - http://mailstripper.eridani.co.uk/
   Mail Me Anywhere - http://www.MailMeAnywhere.com/


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