Milter-greylist

At Fri, 13 Oct 2006 16:19:48 -0000,
Ugo Bellavance wrote:
> 
> --- In milter-greylist@yahoogroups.com, Timothy Alberts <talberts@...>
> wrote:
> >
> > 
> > The only problem I seem to have now is dealing with the long delay when
> > receiving email.  Most of my clients are used to near instant email
> > delivery.  When I first turned it on, it was greylisting for 30 minutes
> > and depending on what the sending server retry was, emails were taking
> > in excess of an hour.
> > 
> > So until I actually run into problems with the program, can I ask for
> > some opinions on the greylisting time delay and what people have found
> > to be a good balance of delivery time versus effective spam blocking?  I
> > just last night reset it to 10m greylisting and that seems to be just as
> > effective at first glance.  My system services 1 domain with 1 mail
> > server and roughly 50 clients.
> >
> 
> We use 1 minute and check frequently for long delays and add domains
> or IPs to greylist.conf, so that legimitate mail servers that don't
> deal well with greylisting don't get greylisted.

I apply greylisting only for suspicious hosts which are found in
DNSRBLs or whose IP addresses seem to be dynamic. In this case the
milter-greylist acts as a backdoor to reduce false positives rather
than a filter to catch spammers.

I feel quite many of spammers are listed in either SpamHaus XBL or
SpamCop Blocking List. In contrast most of legitimate mails are not
delayed. If you hate false negatives, consider to apply content
filters.