On Tue, Nov 02, 2004 at 02:12:20PM -0800, Tor Slettnes wrote:
> >Greylisting is a pain to deal with when you run busy sites, I
> >certainly hope it won't be much more popular than it is today (at
> >least not those which key off the sender host plus the envelope
> >recipient). There's a reason why Yahoo Groups, for instance, have
> >chosen to interpret 4xx as 5xx..
Yahoogroups doesnt treat 4xx as 5xx.. they merely log it as a "soft bounce"
to that user's address, and this counts when processing bounces to weed out
persistently bouncing users.
> I am a bit puzzled by that reaction. In particular for busy sites (at
> least those that receive a fair amount of spam) greylisting would
> essentially reduce the demand for bandwidth and server resources (e.g.
Frankly, speaking as the postmaster of a very busy site (~ 40 million users)
I would much rather prefer that people *not* do graylisting, or callbacks..
all this does is stuff our queues up with unnecessarily delayed email, and
increase the number of smtp connections to our MXs, especially when someone
forges one of our domains into a dictionary attack and spams a callback using
site.
Dave Crocker's BATV and CSV proposals sound like just what we have been
looking for, by the way ..
> And typically, after a particular recipient's list of contacts has been
> 'trained', less than 10% of their legitimate mail tends to be subject
> to greylisting in the first place.
And when you have multiple recipients on your server? Millions of recipients?
> I don't think Yahoo! has a deliberate policy of no-retry deliveries
> with greylisting in mind. Their SMTP behaviour dates further back than
> that.
Yahoo (and Yahoogroups) uses qmail.. please do keep that in mind.
> - In the case of spam delivered via an open relay, that proxy may
> generate bounces; some of which will be sent back to forged sender
> addresses, some of which will get frozen in the queue of that relay.
This is correct
> This, too, can be supported per-user, without restricting each mail to
> one recipient. See the links above for details.
This is broken, RFC wise.. and an irritating characteristic of some mail
gateways that allow per user filtering of email (such as messagewall)
srs
--
linux@??? (Suresh Ramasubramanian)
jaharkes@ravel:/usr/src$ mv linux Gnu/Linux
mv: cannot move `linux' to `Gnu/Linux': No such file or directory
jaharkes @ cs.cmu.edu in reply to RMS on linux.kernel
