[Mimedefang] How to turn 'postmaster notify' off

[Kees Theunissen]

On Wed, 23 Aug 2006, Joseph Brennan wrote:

>
>
> --On Wednesday, August 23, 2006 11:25 -0400 Yanick Quirion
> <YQuirion at tranzyme.com> wrote:
>
>> Hi,
>>
>> I'm using sendmail with mimedefang. I'm having problem with spammers
>> that sends an e-mail to un user that doesn't exist on my organization.
>> The server will send a "user unknown" it the sender, but if the sender
>> e-mail address is fake, I will get this:
>>
>> Aug 23 10:27:12 neptune sendmail[22781]: k7NERBHS022778: k7NERCHS022781:
>> postmaster notify: User unknown
>>
>> There is a way to turn off this "postmaster notify"?
>
>
> This is a sendmail question, not a mimedefang question.
>
> The situation you describe is called a double bounce.  The original
> recipient is not valid, and the original sender is also not valid.
> Look at the sendmail documentation for "doublebounce".  You can route
> it to an address other than postmaster.

Keep in mind that invalid recipients and/or senders are not the only
reasons for a message to bounce or double bounce. In general:
a message will bounce if it cannot be delivered for whatever reason.
Possible reasons can be (and are not limited to):
recipient's disk quota exceeded, no space left on the disk where the
mail must be stored, downstream mailserver not online, failing network
components, configuration errors, name server down, etc.
If you as a postmaster want te be informed of this kind of (local)
errors you better keep inspecting the bounce reports somehow.
IMHO there is little, if any at all, gain in routing those reports
to an other address. Routing those reports to /dev/null is a
Bad Thing (tm).

> However, sendmail normally refuses mail for user unknown, and you
> should try to do that instead of mailing a bounce.  Both virus and
> spam mail may contain an irrelevant but valid address as sender, so
> mailing a bounce to the "sender" is not a good idea.

The only good solution is to refuse mail for unknown user as
soon as possible. That means on the _first_ server that your are
controlling.


Regards,

Kees.

--
Kees Theunissen
F.O.M.-Institute for PlasmaPhysics "Rijnhuizen", Nieuwegein, Netherlands
E-mail: theuniss at rijnh.nl,  Tel: (+31|0)306096724,  Fax: (+31|0)306031204