I have an opensmtpd 7.6 mail server on FreeBSD 14.2. Relevant parts of
the config file:
filter check_rdns phase connect match !rdns disconnect "550 no rDNS"
listen on 0.0.0.0 inet4 port smtp tls pki pkiname filter { check_dyndns,
check_rdns, check_fcrdns, senderscore, rspamd }
Sometimes, it works fine. But sometimes, I get:
May 27 02:36:55 mailserver smtpd[9850]: b972fe95620c78af smtp connected
address=205.220.175.42 host=<unknown>
May 27 02:36:55 mailserver smtpd[9850]: b972fe95620c78af smtp
failed-command command="" result="550 no rDNS"
That IP address is from an organization using Proofpoint, one of the
larger email filtering companies, and it does have rdns:
$ host 205.220.175.42
42.175.220.205.in-addr.arpa domain name pointer mx0b-004ead01.pphosted.com.
Why is smtpd bouncing the mail when it does have rdns?
Thanks,
Kenneth
--
Kenneth L. Ingham, Ph.D.
CIS/CSCI Faculty
Central NM College
Albuquerque NM
