Restricting sending mail to domain or group

[admin]

Am Mittwoch, den 05.12.2018, 13:46 -0800 schrieb Joseph Tam:
> On Wed, 5 Dec 2018, Alexander Dalloz wrote:
> 
> [...]
> >
> > Both to be setup on MTA side.
> 
> Agreed.  You can manage your mailing lists with software (e.g.
> mailman),
Actually I tried to avoid introducing another system...

As for now round about 5 people would gain permission to send to this
all alias. We could use mailchimp, as this is already part of marketing
dpt. but I really would like to keep this very simple.

Following possibilities so far:

(1) Either I take care of having a network shared text file with all 
    emplpyees up to date 
(2) Using/introducing a mailing list (mailman // mailchimp)
(3) via postfix smtpd_sender_restrictions smtpd_receiver_restrictions?
    I am not sure if this is really possible
(4) I could setup an internal virtual domain, e.g. vcomapny.com and 
    restrict this domain to only be able to receive mails from @company.com 
    and setup all at vcompany.com group alias.
(5) setup domain wide sieve to only accept mail from all at company.com if
    sender i eieth a, b, or c...

So far (4) and (5) seem to be easy to implement. For me more or less 
the same overhead with (1) but for the user much simpler.

In this case simplicity has priority over giving birth to a feature
that has already an app for to be used with.


> or hack in a filter between the (public) external and (secret)
> internal
> mailing list e.g.
> 
>         # Forwards to grp1-secret@ if sender is approved
>         grp1: |/path/to/check-sender-filter
> 
>         grp1-secret: :include:/path/to/grp1.list
Thanks!

> 
> If spoofing is a concern, you'll have to endow your filter with more
> intelligence.
Its not.

> 
> Joseph Tam <jtam.home at gmail.com>

-M