Re: Rejecting messages based on recipient MTA''s IP address

[J David]

On Tue, Sep 29, 2020 at 2:15 PM Wietse Venema <wie...@porcupine.org> wrote:
> One alternative is to set reject_unverified_recipient

Thanks, I will give this a shot and see if it helps our situation.

> Alternatively, if the IP address range is known, check_sender_mx_access
> will control access by MX record (or A record if the domain has no
> MX record).

This seems to have the same issue as Bill's suggestion of
check_sender_a_access; it's acting on the sender, not the recipient.

While the problem messages I'm trying to catch have the same sender
and recipient, other messages with those senders do have valid
recipients, so we can't select purely on sender due to the resulting
false positives.  Sorry, I should have clarified that in the original
message.

(Blocking messages based solely on having a sender that can't receive
mail, while IMO a very reasonable thing to do, would cause immediate
and severe blowback for us.)

Hopefully reject_unverified_recipient will cover us.

Thanks!