Viktor Dukhovni:
> Likely I am missing some key insight, please pardon any confusion...
The ISP provides a budget of 5 connections/second, enforced at the
firewall level. The OP's logging shows ECONNREFUSED when the Postfix
scheduler rate limits to <1 delivery request per second. How can
that be?
For one delivery request, the Postfix SMTP client gets up to
five ($smtp_mx_address_limit) addresses from DNS, and burns through
those addresses in a split second as they fail with ECONNREFUSED.
Instantly, he has used up his entire 5 connections/second budget
with only one delivert request.
Obviously, the queue scheduler has no idea how many 'connections'
are being used up per delivery request. No amount of scheduler
tweaking will change that.
Wietse
