Re: Checking from-addresses on outbound mail

[Nick]

On 2020-09-02 01:02 BST, Viktor Dukhovni wrote:
> No, I am not talking about mail not being delivered, I am talking
> about Postfix no longer working properly.

Thanks.  Could you please expand on (from your earlier mail) how to do
this -

> If you want to prevent bounces from leaking out to forged sender
> addresses you need to accept and discard messages, rather than reject
> them.

instead of this -

  -o { smtpd_sender_restrictions =
         check_sender_access
            regexp:/etc/postfix/check-sender-access-outbound,
         reject_unverified_sender
     }

?  For check_sender_access I can use the DISCARD action instead of
REJECT, but what should replace reject_unverified_sender?

Thanks,
-- 
Nick