I'm considering Mailman as an alternative. High number of groups, small
number of users, used for internal groups, no interest / need for public
discussion groups. This is about managing our business, not communicating
with the world (although some of our users forward internal mail to
external SMTP servers ...).
Mailman docs seem to be oriented towards a direct connection to the
internet for external mail.
We've got a single opening in the firewall for SMTP (inbound and
outbound), and that's fine by me. Having Mailman running on the mail
server (sendmail) is not a viable option ... but having all mail that
addressed to lists delivered to mboxes on the gateway that are
periodically (10 mins?) retrieved via POP and fed into Mailman would be a
viable option (but I'm open to suggestions). There's no split DNS here,
the MX for Mailman would presumably be the external MX host. When Mailman
needs to distribute externally, outbound mail would go across the external
It's not clear to (from my admittedly limited review of the documentation
thus far) if or how Mailman could be made to function as described.
Suggestions would be welcomed.