With the acl_not_smtp directive and the ratelimit parameter you can limit the number of messages to be sent. But only when the limit comes, when you try to send a message, it is not even added to the queue, but is immediately rejected (for example, the PHP mail () function returns false ). Because of this, messages are simply lost.

The question is how to configure Exim4 so that messages are always added to the send queue, but only limit the speed of processing messages from the queue?

    1 answer 1

    You need to limit not receiving messages, and sending messages from the queue:

    queue_run_max = 5 remote_max_parallel = 1 queue_smtp_domains = 1

    Description of directives.