[Mailman-Users] slow "out" queue

[Mark Sapiro]

Anil Jangity wrote:

>Does mailman actually (if it works) send to 15 recipients at a time - per SMTP session?


Mailman's use of the term session is not consistent with the RFCs. What
Mailman calls SMTP_MAX_SESSIONS_PER_CONNECTION is actually in RFC 821,
2821, 5321 terms, max transactions per session. I.e. one session is
one connection from HELO/EHLO to QUIT and one transaction is one MAIL
FROM and everything that follows up to the next MAIL FROM.

Unless you have some specific MTA reason for setting
SMTP_MAX_SESSIONS_PER_CONNECTION, you should leave it at the default
value of 0 meaning unlimited.

If a message is personalized or VERPd, SMTP_MAX_RCPTS is ignored
because you can't send a personalized or VERPd message to more than
one recipient. Otherwize, SMTP_MAX_RCPTS is the maximum number of RCPT
TO recipients in one MAIL FROM transaction.

Note that 6000 users per 35 minutes is less than 3 per second. This is
extremely slow. I typically see 30 to over 60 recipients per second on
a rather ordinary production server with full VERP.

See my reply to your original post in this thread at
<http://mail.python.org/pipermail/mailman-users/2012-January/072778.html>
and look at the FAQs linked in that post for hints. In particular, do
not do DNS verification of RCPT TO domains during SMTP from Mailman.

-- 
Mark Sapiro <mark at msapiro.net>        The highway is for gamblers,
San Francisco Bay Area, California    better use your sense - B. Dylan