Re: [dspam-users] qmail + vpopmail + dspam

Askar Ali wrote:
> Hi list
> Problem is that one of our domain @xyz.net getting lot of fake emails
> (emails id does not exists on server) , perhaps 100 of email like that
> in few minutes. which consuming lota space in dspam/data.
>
> Here is a sample ids which dspam have to process in any case which are
> not exists
> auqbwpel@xyz.net iblmobi@xyz.net
> ibmgyail@xyz.net ibrahimtrade@xyz.net
> ibwzvinhg@xyz.net icijrde@xyz.net
> igasnjicv@xyz.net igewpjbds@xyz.net igmivrkb@xyz.net
> ihnvumv@xyz.net
>
> (long list :)
>
> Is there is a way via qmail , dspam etc that dspam only process those
> emails which are destine for id which are present on v.domain?
>
> coz if i let dspam process all emails then in few hours i will be out of
> space, also getting extra stoarge will not helps.
>

Askar you need a way in qmail-smtpd to verify the existence of a rcpt
before it accepts the email. If the user does not exist, the email is
rejected at the smtp phase, rather than accepting the mail and trying to
figure out what to do with it once it has already hit the queue.

qmail all by itself does not have this capability, so it will have to be
modified to get it.

Antonio Nati has such a patch for qmail-smtpd which is commonly referred
to as the chkusr patch. It is intended for use on systems running
vpopmail, so this is exactly what you are looking for. With the patch
in place (in qmail-smtpd.c) it links in vpopmail's headers and therefore
is able to use vpopmail functions to check the existence of the rcpt
before the SMTP DATA phase. If the rcpt doesn't exist it 550's the
rcpt, which puts the ball back where it belongs, in the remote MTA's court.

I used variations of this patch for almost 3 years on a rather
customized qmail-based setup and it works great. Antonio is a really
nice guy too and has done a lot to expand his patch's functionality.

Here is his web address where you can read all about the different
versions of his patch and how to apply it:

http://www.interazioni.it/opensource/

The vpopmail list archives have a lot of good posts from Antonio in
there as well.

As of this week I no longer run a vpopmail/qmail-based setup here
anymore, I have finished migrating everything over to Postfix. qmail is
a decent mailer, especially if you patch it to add the features that
currently-maintained MTA's have (ahem...), but I needed to learn a mail
system we can support our customers using where I work these days, and I
have no interest in learning Sendmail. ;)

Tell Antonio I said hi.

Vince Worthington, RHCE
Received on Tue Dec 13 22:36:08 2005