--On 13 January 2007 16:20:17 +0000 Peter Bowyer <peter@???> wrote:
>
> But for most people, running SA is the most expensive test they do,
So, the question is are we doing greylisting to save IT resources, or to
stop spam from reaching humans (don't forget, they're a resource too!). If
you don't have the resource to scan all your spam, then you might prefer to
greylist before scanning. Alternatively, you might be more concerned about
losing wanted mail as a result of broken or mismatching sender retry
policies - in that case, you want to avoid greylisting mail that
spamassassin says is OK.
> and they move it to last place in the chain for this reason.
> Greylisting is seen as a cheap way of turning away likely spam without
> having to go to the expense of content-scanning it. If SA is involved
> in the greylisting algorithm, the resource saving it delivers is
> significantly reduced. That is, unless the resulting improvement in
> the algorithm leads to better whitelisting and less SA work later.
>
--
Ian Eiloart
IT Services, University of Sussex
