Re: [exim] Greylistd

On 11/29/06 8:42 AM, "Dean Brooks" <dean@???> wrote:

> I also think it is a significant mistake to only retain the
> information for 24 hours. If a server is proven to retry, why would
> you continue to greylist? At that point, the *only* thing you are
> accomplishing is delaying email. It is better to leave the
> information in there for 30 to 60 days, in my opinion, if you know the
> server will retry properly.

36 days is a "friendly" retention time in that it covers repeated messages
sent on each n-th day of the month. That is, for example, a newsletter sent
on the first Monday of each month.

You will find it essential to have a whitelisting mechanism. (Our whitelist
database serves multiple purposes, including valid senders failing
greylisting, exempting neighbor ISPs and well-known ones from greylisting
(they're going to retry anyhow), and carving exemptions to other policy
blocks not related to greylisting. It just reached 750 records today.)

We rolled our own because none of the available solutions seemed robust when
we made the decision to do greylisting (in 2001).

--John