On 11/02/2019 09:46, Michael A. Peters via dovecot wrote:
However the majority of spammers do not spam with a properly configured Reverse DNS - so detect the list header >and skip DMARC if list headers are present AND Reverse DNS matched the HELO/EHLO
A hell of a lot do, though (this is pretty average percentages here)
Accepted 70.07% Rejected 29.93%
Total 100.00%
5xx Reject relay denied 4.27% 5xx Reject unknown user 7.93% 5xx Reject sender address 7.32% 5xx Reject unknown client host 52.44% 5xx Reject RBL 3.66% 5xx Reject milter 24.39%
Total 5xx Rejects 100.00%
unknown client host was high as 95% up till about 10 years ago, so they are slowly learning.
-- Kind Regards,
Noel Butler
This Email, including any attachments, may contain legally privileged information, therefore remains confidential and subject to copyright protected under international law. You may not disseminate, discuss, or reveal, any part, to anyone, without the authors express written authority to do so. If you are not the intended recipient, please notify the sender then delete all copies of this message including attachments, immediately. Confidentiality, copyright, and legal privilege are not waived or lost by reason of the mistaken delivery of this message. Only PDF and ODF documents accepted, please do not send proprietary formatted documents