[Mailman-Users] Why are mails not being sent to all users (mails seem to disappear)?

Till Dörges doerges at pre-sense.de
Thu May 9 17:06:58 EDT 2019

Hi Mark,

thanks for your quick answer!

Am 09.05.19 um 14:31 schrieb Mark Sapiro:

> I assume there's nothing in /var/lib/mailman/logs/smtp-failure since if
> there were, these would also be recorded as bounces.

/var/lib/mailman/logs/smtp-failure does not have any entries related to the issue.

>> But overall I'm only able to find roughly half in either /var/log/mail or
>> /var/lib/mailman/logs/*.
> Mailman did complete SMTP to Postfix for all 416 recipients. The
> /var/lib/mailman/logs/smtp log entry verifies that.  What happened after
> that is a Postfix question.


IIUC it seems in deed as if messages were lost between Mailman and Postfix, without
any of them noticing/logging it.

The only indication I could find that there /might/ be problem was this warning with
a suitable timestamp:

--- snip ---
... postfix/master...: warning: service ... has reached its process limit "10": new
clients may experience noticeable delays
--- snap ---

>> Do I have any chance of finding out what happened to the mails to the addresses which
>> don't appear in any of the log files?
> I don't think this should happen without Postfix logging something, but
> if I have to guess, I'd guess you are not VERPing delivery to Postfix
> and the list is not personalized so Mailman is delivering to Postfix in
> transactions with up to SMTP_MAX_RCPTS (default 500) per transaction and
> Postfix's smtpd_recipient_limit is less.

Postfix is configured with 1000:

  smtpd_recipient_limit = 1000

Neither SMTP_MAX_RCPTS nor VERP_DELIVERY_INTERVAL was set explicitly, so I guess the
defaults from /usr/lib/mailman/Mailman/Defaults.py are being used:


> I suggest you set SMTP_MAX_RCPTS = 10 or 20 in mm_cfg.py or better set
> VERP_DELIVERY_INTERVAL = 1 to enable VERP on all deliveries.

I will try with VERP_DELIVERY_INTERVAL set to 1, to see whether all messages are
accounted for then.

IIRC, setting VERP_DELIVERY_INTERVAL = 1 effectively means to ignore SMTP_MAX_RCPTS
and only submit 1 mail at a time to the MTA.

Curiously for the message that was not delivered to the specific user I did /not/
find a message by Postfix like the following in /var/log/mail:

--- snip ---
... to=<LISTADDR>, relay=local, delay=0.58, delays=0.01/0/0/0.57, dsn=2.0.0,
status=sent (delivered to command: /usr/lib/mailman/mail/mailman post <LIST>)
--- snap ---

To me that looks as if Postfix did in deed not complete sending all messages.

I will monitor the situation with these reduced rate settings applied.

Thanks again -- Till
Dipl.-Inform. Till Dörges                  doerges at pre-sense.de
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