Emmanuel Fust?:
> Le 07/07/2021 ? 15:06, Wietse Venema a ?crit?:
> > Viktor Dukhovni:
> >> On Tue, Jul 06, 2021 at 12:56:50PM +0200, Xavier Beaudouin wrote:
> >>
> >>> I currently have an appliance that misuse the null sender (mail
> >>> from:<>) to send mail.
> >>>
> >>> Unfortunatly, this appliance is closed source
> >>> and we can only setup : fixed ip address and recipient address on GUI
> >>> (nothing else, even if I try to h4x0r the configuration file).
> >>>
> >>> Is there any good advice I can have to make the internal relay server
> >>> which is postfix based to rewrite the null sender to something
> >>> cleaner... but ONLY for the device that use postfix as internal relay
> >>> server?
> >> This requires a content filter or milter, that replaces the envelope
> >> sender address for messages from the client IP address in question.
> >>
> >> There is no built-in feature that performs sender address rewrites
> >> conditional on the client IP address.
> >>
> >> The milter should be easy to implement.
> > There is another option:
> >
> > 1 - Configure a Postfix smtpd process on an additional IP addresss
> > or TCP port that only this client will connect to.
> >
> > 2 - Configure that smtpd process with an smtpd_command_filter that
> > replaces "MAIL FROM:<>" with the preferred address.
> >
> > # Listen on port 1234
> > /etc/postfix/master.cf:
> > 1234 inet .. .. .. .. .. smtpd
> > -o {smtpd_command_filter = pcre:/etc/postfix/command_filter}
> >
> > # Listen on IP address 1.2.3.4
> > /etc/postfix/master.cf:
> > 1.2.3.4:smtp inet .. .. .. .. .. smtpd
> > -o {smtpd_command_filter = pcre:/etc/postfix/command_filter}
> >
> > /etc/postfix/command_filter:
> > /^(MAIL FROM:)\s*<>/ MAIL FROM:<u...@example.com>
> >
> > Wietse
> And use a client_access map in smtpd_client_restriction
> check_client_access with a filter action and you will transparently get
> the intended behavior without specific client configuration.
NO FILTER is needed for the stated purpose: replace
the null sender address.
Wietse
