[Mailman-Users] Messages silently disappearing

[Harald Meland]

[Edward S. Marshall]

> [...] Basically, everything seems like it's working, until you send
> a message to the list.
> 
> The message is archived, and a log entry is made in the "post" log about
> the message, and that's it. Nothing is sent to anyone.

The log message comes from around line 1156 of
.../Mailman/MailList.py, so things probably work OK that far.  Shortly
after that, control is passed over to
Mailman.Deliverer.DeliverToList(), which pipes the message into
.../Mailman/scripts/deliver (and, at around line 175 of
.../Mailman/Deliverer.py, logs non-zero exit codes returned to the
"deliverer" log).

The "deliver" script splits the message receivers into appropriate
(domain-ordered) groups, and then for each group pipes the message
into .../scripts/contact_transport .

contact_transport enqueues the message (in the Mailman queue) and
calls Utils.TrySMTPDelivery() -- which uses the Python "smtplib"
module to communicate with the MTA on port 25 of `mm_cfg.SMTPHOST'.

By default (i.e. imported from .../Mailman/Defaults.py),
mm_cfg.SMTPHOST is "localhost" -- to override this, edit
.../Mailman/mm_cfg.py.

If there is a problem contacting the MTA, hints on how to resolve it
should be logged to .../logs/smtp-failures.

(Yes, I'm learning this myself as I try to explain :)


If none of the above rings a bell why things isn't working, you could
try inserting debug prints at strategic places in the flow to pinpoint
(approximately) where your installation deviates from what you'd
expect.  If you do this, the developers might be interested in what
you find -- in order to fix Mailman and/or be able to help other
Postfix+Mailman users.
-- 
Harald