[BlueOnyx:22490] Re: Backscatter problem

Michael Stauber mstauber at blueonyx.it
Tue Nov 13 16:54:55 -05 2018

Hi Chuck,

>From the other things I've read her in this topic my impression is that
you're looking for a technical solution for an organizational problem.

Indeed just using plain email for your client is the main source of the
problem. They still could use plain email clients to send out their
SPAM, but they need to be educated to do it right. Like setting a proper
Return address.

Even that would not eliminate the problem that their email database
contains a ton of dead-wood that will result in bounces.

And that is the point where a proper mailing software comes in. One that
manages bounces. Like Mailman does. If it sees repeated bounces from
certain addresses, then it will put further email delivery to that
address on hold. And it's not just Mailman which does it, but pretty
much most promotional, email-marketing or CRM tools that use email.

On top of that your client gets something they can manage in a browser,
can use HTML-Emails, ability to manage email recipient databases and
organize them by campaigns as well as statistics about how effective
their emails are.


I once used to use OpenEMM and something like that would be ideal for
the purposes you described:


Back to the server side of things for a moment:

Here the problem is twofold:


Bounces by default to back to the sender or to postmaster. You could set
up a procmail-rule that moves them to /dev/null for instant deletion
when they come in.

Undeliverables in the queue:

So your queue fills up with emails to long dead email accounts or
accounts which block email from you due to you being on RBLs or being
blocked due to past email activity?

By default the Sendmail on BlueOnyx queues these emails for five days
(on 5209R) or seven days on older BlueOnyx before it gives up. When it
gives up sender and/or postmaster get the NDA-notice. Again this could
be redirected to /dev/null via a custom procmail-rule.

This can be adjusted in sendmail.mc:

[root at 5209r mail]# cat /etc/mail/sendmail.mc|grep QUEUE
dnl define(`confTO_QUEUEWARN', `4h')dnl
dnl define(`confTO_QUEUERETURN', `5d')dnl

As you can see: It warns after 4 hours of undeliverability and returns
to sender after 5 days.

You can simply adjust these two to your liking and then rebuild the
sendmail.cf this way:

cd /etc/mail
make all

With best regards

Michael Stauber

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