Eliminating "noise" from secondary MX

Karl Pielorz kpielorz at tdx.co.uk
Mon Jun 23 08:40:57 PDT 2003

--On 23 June 2003 08:48 -0600 Brett Glass <brett at lariat.org> wrote:

> [snip]
> The secondary mail exchanger tries to send the message on to its
> destination, but the mail is bounced by the primary mail host (either as
> spam or because it has been sent to an invalid address). So, the
> secondary dutifully tries to notify the sender that the message didn't
> get through.
> Of course, the "From:" and "Reply-to:" headers of the spam contain either
> a completely bogus address or one that has quickly been shut down due to
> spamming. So, the host, not knowing what else to do, sends a notice to
> Postmaster, saying that the notice to the sender could not be delivered.
> What's the easiest way to suppress this resource-consuming, mailbox
> clogging chain reaction?

Carefully check out the sendmail "Double Bounce Address" option, with a 
view to piping it to /dev/null [Like I said, 'carefully' check this out :)]

Or, secondly - as was cleverly suggested to me a while ago - setup a 3rd MX 
that has a IN A PTR to your primary MX, and make it the highest priority...


mx0.mydomain.com   PRI   20
mx1.mydomain.com   PRI   30
mx2.mydomain.com   PRI   40 (Which is really just a different name for mx0)

That way, you'll probably find most the spam hits the highest priority MX 
(which is, in reality your primary MX).


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