Hi,
I'm hoping I can ask this question here. Somehow the PBL considered the IP
addresses given to us by our ISP (I can share this if needed) as ineligible
to send email, resulting in any recipient domain that checks the PBL to
reject our email, including every email sent to a Microsoft 365 domain.
This is also despite having a rule to bypass spam filtering on the M365
side with our own M365 domain - apparently that is not bypassed?
Does anyone know how this might happen? I've now delisted all of our IPs
successfully, and mail is again flowing, but it obviously resulted in a
pretty significant impact on our delivery.
I'm also trying to confirm I've configured my system properly to best
utilize RBLs.
smtpd_recipient_restrictions =
reject_non_fqdn_recipient,
reject_non_fqdn_sender,
reject_unlisted_recipient,
reject_unknown_recipient_domain,
permit_mynetworks,
reject_unauth_destination,
reject_rbl_client zen.spamhaus.org=127.0.0.[2..11]
reject_rhsbl_reverse_client dbl.spamhaus.org,
reject_rhsbl_sender dbl.spamhaus.org,
reject_rhsbl_helo dbl.spamhaus.org,
reject_rbl_client b.barracudacentral.org=127.0.0.2
...
Any suggestions greatly appreciated.
Thanks,
Alex
