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

[Michael McConnell <soruk at eridani.co.uk>]

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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