Dump incoming mail rather than bouncing?

unruh

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Nov 1, 2011, 6:08:32 PM11/1/11

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My machine running postfix will, when it gets mail for a user who does
not exist on the machine, bounce the mail. I would ratehr it simply
dumped it and not send back a reply to the offending source. How do I
set up postfix to do that for me?

J G Miller

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Nov 1, 2011, 7:33:05 PM11/1/11

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On Tuesday, November 1st, 2011 at 22:08:32h +0000, Unruh wrote:

> My machine running postfix will, when it gets mail for a user who does
> not exist on the machine, bounce the mail.

Do you understand the difference between rejecting mail and bouncing mail messages?

<http://www.dontbouncespam.ORG/#BVR>

Your mailer will only be able to bounce a mail message if it first accepts it,
in the simplest case you should be rejecting non-deliverable mail.

<http://www.postfix.org/BACKSCATTER_README.html>

If you do not want to reject the mail but have it discarded then you need
to know that mail delivery with a Postfix system, unlike most other mailers,
consists of two parts -- the Postfix MTA and "local" the MDA.

What the Postfix system also allows is the configuration of a filter
between the Postfix MTA and local MDA, and it is here that you need to
setup a filter to discard or quarantine for further analysis external
e-mail messages bound for undeliverable local addresses.

<http://www.postfix.org/FILTER_README.html>

It is most disconcerting that you are running a mailer connected
to the Internet and have not consulted the readily available HOWTO
information for that mailer on its web site.

Jasen Betts

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Nov 3, 2011, 4:03:07 AM11/3/11

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In general you set up a "catchall" alias with the destination /dev/null
I don't know the specifics for postfix

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J.O. Aho

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Nov 4, 2011, 7:33:46 AM11/4/11

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Jasen Betts wrote:
> On 2011-11-01, unruh<un...@physics.ubc.ca> wrote:
>> My machine running postfix will, when it gets mail for a user who does
>> not exist on the machine, bounce the mail. I would ratehr it simply
>> dumped it and not send back a reply to the offending source. How do I
>> set up postfix to do that for me?
>
> In general you set up a "catchall" alias with the destination /dev/null
> I don't know the specifics for postfix
>

This will increase the traffic on the machine, as you will accept the mail and
let the sender to send all the date and then pipe it to /dev/null.

If you use the default, then the postfix will just notify the sender that
there is no such user and will not receive the mail body.

If silently accepting everything, you will see an increase of incoming spam
and spammers will start to use bogus sender addresses using that mail domain.

--

//Aho

unruh

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Nov 4, 2011, 12:27:05 PM11/4/11

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Much spam does not accept the bounce message anyway. The problem I am
having is that the mail is forwarded by a second machine. When the first
bounces, the bounce message gets sent back to the second machine, which
is unable to deliver it, and the bounce messages clog up the mail
delivery queue. I would like that first machine to silently drop the
message, refusing to accept it, but not generating a bounce message.

Richard Kettlewell

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Nov 4, 2011, 12:31:32 PM11/4/11

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The arrangement used here is that the system you're calling the 'second'
machine - i.e. the first one to see the mail - uses SMTP call-forwards
(and a cache) so that it can reject misaddressed mail at SMTP time
rather than synthesizing a bounce when the eventual target rejects it.

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Ivan Shmakov

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Nov 4, 2011, 1:07:04 PM11/4/11

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>>>>> Richard Kettlewell <r...@greenend.org.uk> writes:

[…]

> The arrangement used here is that the system you're calling the
> 'second' machine - i.e. the first one to see the mail - uses SMTP
> call-forwards (and a cache) so that it can reject misaddressed mail
> at SMTP time rather than synthesizing a bounce when the eventual
> target rejects it.

Strange coincidence as it seems, but it's exaclty the feature I
had in my wishlist. Thanks!

(Aimed with the correct keyword, I was quick to discover that
it's implemented in Exim [1], which is my MTA of choice.)

[1] http://www.exim.org/./exim-html-current/doc/html/spec_html/ch40.html#SECTcallver

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