On Mon, 22 Feb 2016, Wietse Venema wrote:
If you did not change any of the _destination_recipient_limit settings, this will send 240 messages per hour to the ISP. It also rate-limits all other Postfix delivery agents (local delivery, in particular).
Wietse, I can live with a 15s delay locally; incoming mail is never heavy as there are only a couple of us users here.
For example, one would use smtp_destination_rate_delay to rate-limit only deliveries with the "smtp" delivery agent.
That's what I thought.
You should set default_destination_concurrency_failed_cohort_limit=10 in main.cf (or smtp_destination_concurrency_failed_cohort_limit=10 if you decide to use smtp_destination_rate_delay instead of default_destination_rate_delay).
I've no preference and will use both smtp_destination_rate_delay and smtp_destination_concurrency_failed_cohort_limit. Thank you very much, Rich