hello all, I am used to have in the config reject_unknown_hostname in the smtpd_helo_restrictions and for literally years my mailserver were good.
BUT in the last months, say from the start of the year i am rejecting more and more messages from reliable sources as the mail servers of pieces of italian government and some very big ISPs like FastWeb. My log files are filled with (example) Sep 16 06:42:00 server1 postfix/smtpd[4257]: NOQUEUE: reject: RCPT from wr001msr.fastwebnet.it[85.18.95.77]: 450 4.7.1 <wr001msr.intranet.fw>: Helo command rejected: Host not found; from=<VALID_ADDRESS> to=<VALID_ADDRESS> proto=ESMTP helo=<wr001msr.intranet.fw> for a transaction of a prefectly valid test email i sent to myself. More and more i see large installations with EHLOs to some local intranet names and thus not resolvable host names in dns provoking the reject in my postfix. Is it also your experience? Has reject_unknown_hostname less and less use in favour of other anti-spam methods? because in a server with 5000 mailbox and 80k-100k messages a day, that setting free me of 20k-30k spam messages easily, but catch these large institutions. i am just a bit confused. what is your experience on this? Thank you -Andrea-
