blocking annoying 'bounce mail' "feature" from customers use.

[jeroen at unfix.org (Jeroen Massar)]

On 2011-May-25 18:09, Eric J Esslinger wrote:
[..]
> Does anyone know of a way for me to block the following, using
> postfix, either via refusing to accept the mail or by dropping it in
> /dev/null: Mail from <> or postmaster that originates within our
> customer IP blocks/is sent using authentication at the submission
> port and/or that does not have a valid local recipient.

http://www.postfix.org/header_checks.5.html

But you should be lucky your customers are actually using your SMTP
relay in the first place instead of just bouncing directly to the target MX.

Greets,
 Jeroen