[Mailman-Users] slow "out" queue

Anil Jangity anilj at me.com
Thu Feb 23 00:29:00 CET 2012

Mark, thanks for the very detailed info below.
I am still stuck on this.

This sendmail server is setup to relay the mail to smarthost. When I inject a test mail on port 25 with RCPT and FROM to be a made up junk domain, the email is still delivered *immediately* to the smarthost, there is no resolver issues.

If sendmail was really doing DNS lookups, I would think it would be stuck locally or throw a bounce/error right away.
It just seems like it's running serially, and not dequeueing multiple messages to the smarthost at a time.

PS: Putting a local DNS cacheing server is a possibility, but not yet.

On Feb 1, 2012, at 10:56 PM, Mark Sapiro wrote:

> 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

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