[Workaround.org] Preventing backscatter with Postfix

Dennis Guhl guhl at ikt.de
Fri Jul 30 13:32:12 CEST 2010


On Fri, Jul 30, 2010 at 10:06:42AM +0200, Oliver Ladner wrote:
> Hello all,
> 
> Recently my mailserver got re-listed at backscatterer.org, an RBL
> run by the infamous UCEPROTECT guy(s).

Nothing to be hilarious about.

But also nothing to be too concerned about.

> I read http://www.postfix.org/LOCAL_RECIPIENT_README.html#change and
> so I added this to my main.cf:
> 
> local_recipient_maps = $virtual_mailbox_maps

Why the heck did you cange your local_transport? Nothing in the
tutorial tells you to do so.

Tell us what you want to achieve, what does not happen the way you
want it to happen and prove your claims. Provide the output from
postconf -n and show the full log for one mail triggering to send
backscatter.

[..]

> I don't think amavis is the problem, my configuration is as follows:

It have nothing to do with this in the form you might belive. But ist
*is* on of the reasons you are prone to be a source of backscatter:

1. You don't sufficiently probe for not existing accounts at the SMTP
level.
2. You don't use amavis as smtp_proxy_filter and you don't forbid
amavis to send NDRs if it can not deliver a mail.

How to solve this I will give you further pointers after you told us
what it is about your setup.

In the meantime I recommend you read
http://www.postfix.org/BACKSCATTER_README.html.

[..]

Dennis


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