Re: Is gray-listing a one-shot anti-spam measure?
On Fri, 03 Dec 2004, Russell Coker wrote:
> Henrique recently stated the belief that gray-listing is a one-shot measure
> against spam (see the above URL) and that spammers would just re-write their
> bots to do two transmission runs with a delay in between.
Yes.
> A delay of transmission means more time for the spamming IP address to be
> added to black-lists. So during the gray-list interval (currently 5 minutes
True. But in that case, we also need the greylisting period to be long
enough for the blacklisting to happen, *and* we might need special provision
on the spamtraps too.
Assuming greylisting gets realy widespread (otherwise spammers would not be
doing retries in the first place, I suppose), spamtraps might also have to
do greylisting (or spammers could just stop delivering for non-greylisting
sites, which is something quite weird to think about but...). So we would
need various levels of greylisting.
> Currently gray-listing can be used on it's own with no other anti-spam
> measures and still do some good. This situation will change. But I believe
> that in combination with other anti-spam measures it will still offer
> considerable benefits even after spammers wake up to it's presence.
You're probably right. So please let me revise my point: greylisting by
itself is a one-shot deal, let's use it while we can. greylisting as a
delay measure for blacklists to catch up before you deliver the email will
continue working well (i.e. not an one-shot deal), IF the blacklists DO
manage to catch up during the greylisting time AND we can keep them doing
just that when greylisting gets very widely deployed (greylisting could
interfere with the listing delays, after all).
Russell, how fast are the blacklists reacting to ongoing spam runs on the
systems you pay attention to? I don't have that data for mine :(
> Henrique, please don't take this as a flame. I am writing to you because you
I didn't...
--
"One disk to rule them all, One disk to find them. One disk to bring
them all and in the darkness grind them. In the Land of Redmond
where the shadows lie." -- The Silicon Valley Tarot
Henrique Holschuh
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