Re: [exim] greylisting is inverse rate limiting

On Thu, 2009-09-17 at 22:17 +0200, Heiko Schlittermann wrote:
> Comments?

Only one: if you do this as detailed you will regularly delay mail which
arrives once every 24 hours.

IMO, and in most greylisting implementations, once a sending host has
proved itself to be "well behaved" then there's no point making it wait
every 24 hours. All that will do is delay future mail.

Using obvious terminology, a greylist entry exists because some set of
conditions haven't been fulfilled to make a whitelist or blacklist
entry. If the host proves to be "good", elevate it to the whitelist and
do other checks. If it continually proves to be "bad", move it down to
the permanent blacklist and don't be bothered by it again.

Of course, you can slide the timers around so hosts don't, for example,
permanently remain blacklisted (or whitelisted) but that a local policy
decision. If you have a local policy which dictates that sending hosts
with a frequency of 1 connection per 24 hours will always be delayed,
that's up to you!

Graeme