[SURBL-Discuss] Hi I'm new and I like SURBL

Jeff Chan jeffc at surbl.org
Tue Dec 7 15:01:28 CET 2004


On Tuesday, December 7, 2004, 5:50:05 AM, Paul Schwarz wrote:
> I'm using XWall and this is what it states:

> -----------------------------------------------------------
> GreyListing

> GreyListing spam filter, based on http://projects.puremagic.com/greylisting


> The GreyListing method looks at three pieces of information about any
> particular mail delivery attempt:

> The IP address of the host attempting the delivery 
> The envelope sender address 
> The envelope recipient address 
>>From this an unique triplet for identifying a message is created and if this
> triplet was never been seen before, or the sender is not excluded or on the
> white list, then the message delivery is refused with a temporary failure.

> Any normal SMTP server will reschedule the message and will resend it after
> some time 
> ( usually 10 - 15 minutes ).

> Spammers however are sending applications designed specifically for
> spamming. These applications usually adopt the fire-and-forget methodology.
> That is, they attempt to send the spam to one or several MX hosts for a
> domain, but then never attempt a true retry as a real SMTP server would.

> There are some misbehaving mail servers that have a problem with GreyListing
> and XWall automatically excludes them. You will find the list at GreyListing
> Exclusions

> Note: Make sure your backup MX SMTP also runs XWall or any other SMTP server
> that support GreyListing or else the spammer will bypass XWall by sending to
> XWall first and then to the backup MX.

 

> Max triplets to gather

> Defines how many triples XWall should member
  
> Initial delay of a previously unknown triplet
> Lifetime of triplets that have allowed mail to pass
> Lifetime of triplets that have not yet allowed a mail to pass

> Defines the time interval of the triples
  
> Show detailed triplet description (last seen, time elapsed)

> If this is enabled XWall shows a detailed description about the status of
> the triplet, 
> including the last seen and elapsed time.
   
> -----------------------------------------------------------

Thanks.  That matches the usage of the term greylisting
that Dave mentioned.  It's probably a somewhat reasonable
approach, though it may itself be RFC non-compliant.  I'm
sure others have looked into that issue though I haven't.

Jeff C.
--
"If it appears in hams, then don't list it."



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