Re: [exim] More embedded Perl functionality

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.

We certainly whitelisted our "neighbor" ISPs...an ISP in Maine would likely
not need to whitelist that group. We also whitelist the big places that
send us mail*. More generally, why delay messages we know we're going to
accept eventually, and why build up the queues at the big places?

*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.)

--John