[nzlug] (OT) Sorbs etc, was Exim: Limiting outgoing connections on Debian

[Simon Lyall]

On Sat, 7 Oct 2006, Robin Sheat wrote:
> On Friday 06 October 2006 16:51, Donald Gordon wrote:
> > Greylisting is not terribly wonderful. =A0It cuts down on some spam, bu=
t
> > breaks an expectation that many users have: that their email is sent
> > instantaneously. =A0
> There should be no expectation that mail is delivered instantly. The stan=
dard
> is to get a notice that it hasn't been delivered after 5 days. Besides, t=
he
> delay only happens once, and is usually 5 minutes. You can't expect someo=
ne
> you've never emailed before to respond to an email within 5 minutes anywa=
y.

I don't know what planet you live on but where I live people are paid
money to run mail systems and the expectation is that 99% of email should
go though with 10 seconds or so and the is pretty much achieveable.

People are commonly on the phone talking and will say "I'll just send you
that" and expect to be able to discuss the document within seconds.

People who impliment grey listing should be aware they are breaking this
expectation. Not to mention that their assumptions about retry behavours
of email servers doesn't always match reality[1].

Oh, and long term if grey listing gets common enough the spammers will
just work around it and then you are just back where you started except
you have made part of the SMTP protocol useless and delayed everybody's
email.

[1] - eg some Servers won't retry for a couple of hours, others will
in less time than the greylist minimum, others will have a central queue
server by several mail machines so it won't be the same server retrying
the second time around.

--=20
Simon J. Lyall  |  Very Busy  |  Web: http://www.darkmere.gen.nz/
"To stay awake all night adds a day to your life" - Stilgar | eMT.