[Mailman-Users] Mailman 3: Deployment without LMTP

[Michael Hierweck]

Hi all!

We are currently running Mailman 2 in an very low-traffic environment
without access to the mail server configuration. We can either use
.forward or aliases to forward mails directly to Mailman via pipe.
Fetching mails from POP3/IMAP mailboxes would be possible, too.

We would like to upgrade to Mailman 3 now. Thanks for lots of good work
over many years btw. However Mailman 3 only supports feeding mails via
LTMP. Is is possible to build a bridge between .forward/aliases and
Mailmans LMTP interface in a convenient and secure manner?

An option might be letting fetchmail fetch the mails from a mailbox and
forward them via LTMP. As the mails have already been successfully
delivered to the mailbox before Mailman might reject them I can't image
a chance of handling bounces due to rejects correctly in this setup.

Therefore I'm thinking of a small Python script that receives mail from
stdin and forwards them via LMTP but I'm unsure whether this would be a
correct way to achieve the goal because there might by problems with
bounces when Mailman rejects those mails. This script oughts to
terminate unsuccessfully when the LTMP delivery fails and should
therefore make Postfix bounce the mail itself.

Postfix -> .forward -> pipe --(stdin)--> script --(LMTP)--> Mailman 3

Any opinions or hints are appreciated. Thanks in advance.

Michael