qmail-smtpd receives mail for invalid addresses
David Killingsworth
mail for a
user who doesn't exist, then tries to bounce it, but since its spam/UCE
it has
a bogus return address, and can't be bounced.
I had sendmail set up to verify incoming mail addresses at the
connection
and would reject the rcpt <us...@domain.com> with an error message.
"unknown user"
or "invalid address"
the qmail-smtpd man pages don't say much so I'm sure there is a way to
finagle this
into being.
Does anyone know how?
David.
Dave Sill
> I have noticed that I get a lot of double-bounces when qmail accepts
> mail for a user who doesn't exist, then tries to bounce it, but
> since its spam/UCE it has a bogus return address, and can't be
> bounced.
Right. Mail from a nonexistent sender to a nonexistent recipient can't
be delivered, and the bounce will bounce, too.
> I had sendmail set up to verify incoming mail addresses at the
> connection and would reject the rcpt <us...@domain.com> with an error
> message. "unknown user" or "invalid address"
That's standard Sendmail behavior. It also allows spammers to quickly
determine which addresses are valid.
> the qmail-smtpd man pages don't say much so I'm sure there is a way
> to finagle this into being.
There's not, really. qmail-smtpd lacks the privileges required to
determine which addresses are valid. qmail allows users to manage
their own address spaces via .qmail-* files which might not be
world-readable.
--
Dave Sill <MaxFr...@sws5.ctd.ornl.gov> <http://web.infoave.net/~dsill>
Oak Ridge National Lab, Workstation Support
<http://www.lifewithqmail.org>: almost everything you always wanted to know.