> I see that current setup might be useful in case some user changes MX > before the domain is activated at Fastmail, in which case giving 4xx > could make sense. But it is not right to report such re-tries to sender > score as attempts to deliver to non-existing users.
Yes, this is why we 4xx rather than 5xx email sent to an unconfigured domain. Many inexperienced email users aren't sure exactly what order to change or set things up in and we've seen users lose email before because they changed the MX records before adding their domain at Fastmail. The 4xx response reduces the chance of lost email. In general it doesn't really matter that it's 4xx not 5xx. There's no sensible reason to point MX records for a domain to us if you're not planning on actually using us for your email. If that does happen, the email will eventually bounce when the other side gives up trying to resend, which in most cases is at most 24 hours. Now clearly there's an interesting and unexpected edge case that's happened here. The logging of repeated delivery to a "non-existent" address has been rolled up into a sender score feed that's affected your servers IP reputation, which is really annoying. Unfortunately fixing the code on this is non-trivial right now since in the policy daemon where this logging occurs we don't actually have the information we need to suppress this case there and then. I have some longer term ideas for this, and will keep this scenario in mind when I get to them. Sorry Kirill, I don't have a really good answer right now, though I would say that "emails would be kept in the queue for a month" is probably actively working against you here. There's no reason an email should be queued for that long. 24 hours seems a high upper bound these days and is the postfix default. It's better that it actually bounce sooner to let the sender know that something went wrong rather than trying for a month and the user not knowing that their email is in limbo somewhere. -- Rob Mueller r...@fastmail.fm _______________________________________________ mailop mailing list mailop@mailop.org https://list.mailop.org/listinfo/mailop
