OT - Greylisting (was: Re: gOCR SpamAssassin plugin)

Michael Baird mike at tc3net.com
Fri Aug 11 18:05:18 IST 2006

On Fri, 2006-08-11 at 10:52 -0500, Logan Shaw wrote:
> On Fri, 11 Aug 2006, Jim Holland wrote:
> > Another concern is the impact that greylisting would have on the Internet
> > if its adoption became widespread - it would mean that all mail servers
> > would have to work twice as hard to deliver mail.
> Actually, it's only some mail servers.  Greylisting lets known
> senders through without a delay.  Mail servers that are mostly
> sending messages to recipients who recognize them would not
> see delays.  Mail servers that are mostly sending messages
> to those who don't recognize them would see the delays.  So,
> it makes mail servers up to twice as hard.
> Also, while I agree that it would increase the load, in
> general I think decreasing spam is worth some increased load.
> Sure, it's a slippery slope (one could imagine things getting
> so bloated that it takes 5 minutes of CPU time to deliver one
> message, if we keep on adding limitless spam-fighting strategy),
> but on the other hand, 10 seconds of CPU time spent catching
> spam automatically is cheaper than 10 seconds of a human's
> time deleting it manually.
Greylisting decreases load immeasurably on a mailscanner system, the
cost of greylisting is much less then allowing the message to go through
the mailscanner sytem. I deployed it several months ago, it really is a
good tool, and I've had very few complaints (10000 users).

Michael Baird

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