On Wed, Jul 13, 2011 at 04:57:02PM +0200, Geert Mak wrote:
> is it possible to reject/redirect on postfix level (to a spam catcher account
> we monitor) -
>
> - all mail sent to undisclosed recipients
Why not focus on spam, rather than weakly correlated factors. It is probably
best to deploy a decent spam filter.
> - all mail sent with "our" addresses in From: but not originating from
> us (or mail server is in-house, one server with one IP)
This would be a mistake. For example, you'd never see your own posts to
this list.
This said, you may find that filtering the envelope sender (rather than
the From: header) is reasonably effective. The main collateral damage is
"forward an article" newspaper sites, ... which send email with envelope
address set to the visitor's alleged address.
--
Viktor.
