Patrick Ben Koetter:
> * Stefan Michael Guenther <s.guent...@in-put.de>:
> > Hello,
> >
> > one of our clients wants to offer mass mailing services for his clients.
> >
> > The problem is, that our client wants to send emails with the sender domains
> > of his clients from his own postfix server.
>
> 1. Make sure the sending server has matching forward/reverse DNS resolution
> for the hosts that send.
>
> 2. The client must list the sending servers IP in his DNS SPF record.
>
> 3. The client must publish a DKIM record in his DNS. The sending server must
> use the apropriate DKIM signing key.
I would add one: configure the myhostname parameter such that it
matches the PTR name for the SMTP client IP address. Postfix uses
this name when sending EHLO.
If you are going to send mail on behalf of different customers you
can configure different SMTP client configurations ("transports"
in Postfix parlance) in master.cf each with its unique settings for
smtp_bind_address and smtp_helo_name.
http://www.postfix.org/master.5.html
Then you can use Postfix >=2.7 SMTP server access maps to invoke
actions of the form "FILTER transport-name:" (note final ":") to
choose the SMTP client IP address based on the sender address.
http://www.postfix.org/access.5.html (see "FILTER" action note 3).
Wietse
