Good morning. I am trying to configure Postfix to behave in a certain way, and
after a couple of days of not being successful, here I am.
The use-case I am configuring for is:
* the host's name and domain are not internet-resolvable
("labbox.localdomain", literally true)
* Postfix should only accept email from the local system (easily and
already done)
* Postfix should accept, but log & drop email destined for a specific
list of (internal, internet-invalid) domains (transport_maps, "localdomain
DISCARD").
* In general, Postfix on the host is more-or-less a simple relay - it
accepts email from local applications and forwards everything to a central,
smarter relay. The host is not intended to receive email at all.
The one that's annoying me:
* Intent: Postfix should reject any mail submitted where the "From" is:
either "not blacklisted" or "is whitelisted". Basically I want to force my
users to configure their apps so that they send mail with something other than
the OS default "username@labbox.localdomain". I don't mind using either a
blacklist approach (just list "localdomain"), or a whitelist approach (list
their individual "From" addresses).
+ If I try to send mail from a shell, for example: # echo "test" | mail
-s "test" my.addr...@realdomain.com should be rejected since the From is going
to take the OS default of "root@labbox.localdomain"
I've tried a variety of things in Postfix, so far no luck.
My current line of thought is using smtpd_sender_restrictions, but still
haven't made that work the way I want it.
> (blacklist method)
> main.cf:
> smtpd_sender_restrictions = check_sender_access
> hash:/etc/postfix/sender_access, permit
>
> sender_access:
> localdomain REJECT
> .localdomain REJECT
It seems simple enough but it still lets my test emails go through and they
show up in my inbox as "From root@labbox.localdomain"
I've tinkered around with most of the other options for
smtpd_sender_restrictions, but I'm defeated at this point.
Thanks in advance,
Jeremy Collins, CGI
