On Wed, Nov 03, 2004 at 03:36:33PM -0800, John W. Baxter said:
> On 11/3/2004 11:48, "Tor Slettnes" <tor@???> wrote:
>
> > On Wed, 2004-11-03 at 00:12 +0100, Tore Anderson wrote:
> >> The problem with busy sites and greylisting isn't implementing
> >> greylisting upon reception, but sending to other sites that do use it.
> >> The queue size of the egress MXes will grow painfully large as more and
> >> more sites implement greylisting. Implementing greylisting myself
> >> wouldn't be a problem, the fact that I don't is rather due to altruism.
> >
> > This is an interesting point. However, I think this fear is a bit
> > exaggerated - as I am sure real-world impact on your outgoing mail
> > exchangers is (and will remain) minimal. The key is that greylisting
> > takes effect only on the first contact between a particular sender and
> > recipient - most of the time, people on your site will send mail to
> > people they already have established contacts with. (Typically,
> > "one-off" mails go to non-personal recipients, not on sites that are
> > likely to greylist).
>
> I think that sites which implement greylisting should whitelist not only
> sites like Yahoo Groups which don't work properly with greylisting, but also
> trusted sites which send them lots of email.
This only makes sense. The _only_ point of greylisting is that there is
a mostly true idea that spam doesn't queue and retry. Once you've
established that a remote IP does queue and retry, why bother
greylisting them anymore? A simple cron job that runs over your sql
table, finds an IP with more than some amount of entries in the
whitelist state, and then a dump of those IP's into the whitelist would
do it, I would think. Some additional care to make sure you don't
whitelist an RBL'd host, or some timeout settings and so on would also
be good, but that's the rough idea.
> *Except for the small subset of big places we block instead. (There's one
> which sends us lots of "nigerian" fraud, lottery winner fraud, traffic
> camera spray, etc, and also unfortunately houses some legitimate senders.
> We have about three sender/recipient pairs we special case around the block
> of that sending operation, which is across the ocean from us. The ocean
> doesn't make them low volume when they aren't blocked, but does cut down the
> number of valid sender/recipient pairs that need special handling.)
That's a seperate issue, but I know the feeling.
--
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| steve@??? | policy - there's less competition. Van |
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