Hello.
I have been supporting for years no-profit organizations, that have been
sending a number of mails to 10000 and more recipients at the same time.
After similar initial problems the solution never giving any major issue was
*default_destination_concurrency_limit = 1*
*default_destination_recipient_limit = 25
*
Of course this slows down the delivery, however it is not a big problem
unless all the recipients are handled by a restricted number of MX (and
this is not usual)
I'm now running less intensive mail servers, so maybe some tuning is
need in this phase.
Marco
Il 19. 05. 17 13:39, Wietse Venema ha scritto:
richard lucassen:
Hello list,
For a few reasons I use an outgoing postfix as smarthost. The source
mailserver is an exchange. Before the postfix server was in use,
sending mail to a bunch of recipients at a domain which is hosted by
outlook.com was no problem. When the mail passes through postfix, mail
to many recipients at a domain hosted by outlook.com is delayed and this
is the message I see in the queue:
-Queue ID- --Size-- ----Arrival Time---- -Sender/Recipient-------
EA57C5F8D9 7094 Mon May 15 14:41:09 u...@example.com
(host 358619467.mail.outlook.com[213.199.154.106] said: 452 4.5.3 Too
many recipients (AS780090)
[AM5EUR03FT055.eop-EUR03.prod.protection.outlook.com] (in reply to RCPT
TO command))
Searching a bit I found this setting:
smtp_destination_recipient_limit
This defaults to 50. Is this the right parameter to adjust?
Maybe. In the fight against spam, mail server operators are not
exactly famous for providing accurate error messages.
The SMTP standard says the server should accept 100 or more recipients
in the same MAIL FROM transaction, and it specifies no limit on the
number of MAIL FROM transactions in the same SMTP session. Mail
operators on the other hand may do all kinds of arbitrary things.
Working around this may involve a combination of Postfix rate_delay
and other settings. Donate your eyeballs to your preferred search
engine to find out what other people do. My domain is too small
to provide meaningful experience in this respect.
Wietse
