[Mailman-Users] Patch for use of Postfix VERP support

[Mark Sapiro]

Brad Knowles wrote:
>
>This is a postfix problem.  Find the sites that cause the problems, and set 
>up separate queues for them, with different parallelism and 
>re-queueing/re-try schedules.


Brad,

Normally, I would defer to you for all things MTA as your knowledge and
experience in this area are far greater than mine, but I have been
under the impression that if an MTA has two or more messages to
deliver to the the same remote MX, that it can and perhaps will
deliver them in one SMTP session as follows

connect
HELO (or EHLO)
MAIL FROM
RCPT TO
DATA
.
MAIL FROM
RCPT TO
DATA
.
...
QUIT

I.e., each message will be sent with a separate MAIL FROM, RCPT TO and
DATA, but more than one message will be sent within a single connect,
HELO, QUIT session.

If this is actually done (or can be done) by Postfix, it might help
Fil, since the complaint in Fil's post was

(host mx01.xxxx.xxx[xxxxx] refused to talk to me: 421 4.3.2 Connection
rate limit exceeded.)

in response to a connect request. Thus, if more messages could be sent
over one connection, that would reduce the connection rate even though
it wouldn't reduce the message rate.

Also, I think from earlier messages in this thread
(<http://mail.python.org/pipermail/mailman-users/2009-January/064588.html>
et seq) that Fil is already successfully using Postfix VERPing with
Mailman, so the only question here is can Postfix be convinced to send
multiple messages to the same MX over a single connection.

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