[Mailman-Users] Throttling output

Brad Knowles brad at stop.mail-abuse.org
Wed Jun 14 00:36:01 CEST 2006

At 11:38 PM +0200 2006-06-13, Bernd Petrovitsch wrote:

>>  	I think that this would require a second MTA instance -- the
>  You want that probably anyway since you probably don't want your MTA
>  accept 22.000 emails on a public interface in one rush (and I actually
>  don't remember out of my head how mailman really inject mails. 1 mail
>  with a long list of rcpt-to:?).

	Mailman can do that, depending on how you configure the 
MAX_SMTP_RCPTS parameter.

>>  first instance of sendmail (or whatever MTA) would simply take
>>  everything that Mailman gives it and then store that in the queue.
>>  This would be different from a normal sendmail (or other MTA)
>>  configuration, where immediate delivery would normally be attempted.
>  Yes. But "normally" you don't throw 22.000 emails at once on your MTA.


>  And if you do this "normally", you shouldn't need any throttling or
>  other special behaviour at all - just enough hardware.

	Also true.

>>  	Then, additional queue runners are called to start processing
>>  that queue and pushing those messages out, but they go through an
>>  additional instance of sendmail, where the throttling milter is used.
>  Just limit/throttle the MTA itself (sendmail has several options for
>  this like "number of proceses", etc. and I assume that other MTAs like
>  postfix, exim, qmail allow this too in similar ways).

	Yeah, but so far as I know, none of those mechanisms control the 
number of messages that are sent per period of time.  They control 
the number of a given set of processes you can have at any given 
period of time, but that has only the smallest impact on the number 
of messages sent per hour.

>>  	You would also need to make sure that the first instance of
>>  sendmail (or whatever MTA) is not configured to generate Delivery
>>  Status Notices (DSNs) for delayed messages, because you know for a
>>  fact that some messages are going to be delayed for a significant
>>  period of time, and you don't want those kinds of warnings clouding
>>  the picture for Mailman.
>  Of course. But the standard/usual delay of 4 hours or so should be large
>  enough though (and I don't see a problem in raising that limit).

	I'm not convinced.  If you've got a list of 22,000 recipients and 
a limit of 1000 recipients per hour, it's probably going to take a 
lot longer than four hours to get out all those messages.

	I do remain convinced that if you're trying to do throttling 
because your provider requires it, that you are most definitely using 
the wrong provider.

Brad Knowles, <brad at stop.mail-abuse.org>

"Those who would give up essential Liberty, to purchase a little
temporary Safety, deserve neither Liberty nor Safety."

     -- Benjamin Franklin (1706-1790), reply of the Pennsylvania
     Assembly to the Governor, November 11, 1755

  LOPSA member since December 2005.  See <http://www.lopsa.org/>.

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