Preventing backscatter with sendmail

[Gareth]

Havent been following the spamassassin tread but for postfix to stop
creating backscatter yourself use recipient verification.
To remove backscatter either use the mailscanner watermark feature or if
outgoing mail doesnt allways go through mailscanner then you can use the
spamassassin 'vbounce' plugin instead.

On Thu, 2009-01-22 at 10:24, Pardon Blessings Maoneke wrote:
> Is there a way of preventing backscatters on postfix. I have many
> users and i am using postfix plus mysql database but there is a lot of
> backscatters. How can i prevent such a scenario
> 
> 
> On 1/21/09, Steve Freegard <steve.freegard at fsl.com> wrote:
> > Kai Schaetzl wrote:
> >> Steve Freegard wrote on Wed, 21 Jan 2009 15:04:59 +0000:
> >>
> >>>> I haven't followed this thread much, but would this work alongside or
> >>>> instead of something like milter-null?
> >>> It would work alongside milter-null, scam-backscatter is simply a
> >>> recipient call-ahead milter.
> >>
> >> e.g. it is meant to prevent *yourself* from creating backscatter not from
> >> incoming backscatter. I think the name of this milter is rather confusing.
> >
> > Yes - I agree.
> >
> > I also suspect that due to the name - people will think of this milter
> > as some sort of 'silver-bullet' to prevent backscatter emanating from
> > their host which would be a bad assumption.
> >
> > Rejecting invalid recipients on a gateway machine is a good start; but
> > the administrator has to actually make sure the back-end hosts that
> > actually receive the call-aheads isn't accept-then-bounce (e.g. it
> > accepts all the recipients and the entire message then sends a DSN after
> > the message has been accepted - *cough*Exchange 5.5*cough*) as in this
> > case this milter would be no help; in fact it would actually reduce the
> > efficiency of the gateway as it would carry on doing call-aheads even if
> > the back-end doesn't reject invalid recipients based upon the
> > documentation (see milter-aheads 'is-blind-mx' tests for an example of
> > how to do this right).
> >
> > Many domains mail servers do not reject invalid recipients correctly:
> >
> > [root at mail ~]# ./bmx_check_routes.pl
> > Found 382 domains; pass=4 (1.05%), fail=378 (98.95%)
> >
> > pass = servers that reject invalid recipients
> > fail = servers that accept all recipients
> >
> > Note that the 'fail' statistics could also count domains with
> > 'catch-all' accounts.
> >
> > Regards,
> > Steve.
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> 
> 
> -- 
> 
> Regards,
> Pardon Blessings Maoneke