Diego Pomatta wrote:
But is not qmail's job to detect spam
True.
or tell the sender what the
problem was;
True only for your local site policy; most people who reject spam would
like to let the sender know so legitimate senders can rearrange their
message to try again. More generally, it's usually a good idea to
include *some* kind of information about why you rejected the message if
you reject an email message at the MTA layer.
qmail makes this much more difficult that pretty much any other MTA.
qmail, as provided by DJB, is nearly unusable in today's email
environment IMO.
qmail is just the MTA, and a damn fine one imho.
A filter/scanner/anti-spam tool has to do that.
If you're going to notify senders about spam or virus content, the time
to do it is before your mail system has sent a "250 OK" reply to the
message's DATA segment. Accepting the message then constructing a
(new!) rejection message to send back generates backscatter, and is
likely to get your system blacklisted locally by sysadmins everywhere if
you do this.
Earlier you also wrote:
> If you mean incoming, IN MY CASE I drop spam without further notice to
> the sender or the recipient. I deal with the false possitives
> personally, and configure SA accordingly. Only 2 false possitives
> since SA is in effect, though. And it was actually mail I would
> consider spam, but the user in question wanted to receive it anyway.
2 FPs over what time period? How much overall mail flow? What type of
system is it; how many accounts?
How do you find out about a false positive if you discard anything
tagged as spam?
I don't drop anything but confirmed viruses on my *personal* mail
system, never mind the systems I'm responsible for at work; I shudder
to think of the cries of outrage if I silently dropped spam on the ISP
mail systems I administer. (There *have* been business-related FPs,
more than once.) I *do* *divert* messages considered spam for most
customers to a spam folder, and old spam is expired on a daily basis.
-kgd
