Dnia 12.11.2019 o godz. 10:20:01 Snel.com - Yavuz Aydın pisze: > reject_unverified_sender. It looks like our Postfix server accepts mail > which has a sender www-data@hostname while smtp.antispamcloud.com reject > the same mail for a specific hostname. That specific hostname (a FQDN) is > behind a CloudFlare DNS proxy so I understand why smtp.antispamcloud.com > can't verify the sender. What I don't understand is why Postfix accepts > the mail. The hostname does not have MX records assigned (the parent > domain does and the parent domain has a catch-all account).
If you have an address username@domain and you want to send mail to that address (and Postfix sender verification works just like that - attempts to send mail to the address, and if SMTP transaction is accepted, cancels the attempt and backs out before DATA stage), and "domain" does not have a MX record, then, by RFC, A or AAAA records are checked for "domain". There is no obligation to have a MX record defined for hostname to have mail delivered to that address. Maybe "smtp.antispamcloud.com" simply violates the RFC by rejecting domains that don't have an MX record? (and Postfix does not) -- Regards, Jaroslaw Rafa r...@rafa.eu.org -- "In a million years, when kids go to school, they're gonna know: once there was a Hushpuppy, and she lived with her daddy in the Bathtub."
