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

Brad Knowles brad at shub-internet.org
Fri May 15 07:40:22 CEST 2009

on 5/14/09 7:58 PM, Mark Sapiro said:

> 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

My understanding is that the issue here isn't so much the single SMTP 
connection, which may or may not get re-used, depending on the queueing 
strategy of the sender.

If you want to increase your efficiency in this area, then you make sure 
that your submission actually just puts the message into the queue in 
deferred mode and doesn't make an immediate delivery attempt, and of 
course you turn off all spam and other access control checks on the 
outbound side, since you should have already done all those on inbound. 
  You then allow later queue runs to come along and pick that up, along 
with any other messages bound for that destination.

I think we cover this in the various "performance" articles in the FAQ Wiki.

My understanding is that the issue here is whether or not the VERP'ed 
format will be understood and usable by Mailman if there is a bounce, 
and how many unique messages will be delivered, as opposed to how many 
connections will be created to deliver the messages.

Brad Knowles
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