I have a SMTP server named smtp-ca.mdpi.com and when sending emails to some specific chinese email domains, I am getting back:
550 Requested mail action not taken: Invalid IP<64.15.147.140> (in reply to end of DATA command))
I have an SPF set in the TXT of the domain. The rDSN is working fine.
Any idea why this happens?
Thank you in advance.
EDIT: Here is the postconf -n configuration
alias_maps = hash:/etc/aliases
append_dot_mydomain = no
biff = no
config_directory = /etc/postfix
inet_interfaces = 127.0.0.1 10.10.0.10
local_transport = error:local delivery is disabled
mailbox_size_limit = 0
message_size_limit = 102400000
myhostname = smtp-ca.mdpi.com
mynetworks = 127.0.0.0/8 10.10.0.0/24
myorigin = /etc/mailname
readme_directory = no
sender_canonical_maps = hash:/etc/postfix/sender_canonical
smtpd_banner = $myhostname ESMTP $mail_name (Debian/GNU)
smtpd_client_restrictions = permit_mynetworks, reject
virtual_alias_maps = hash:/etc/postfix/virtual_aliases
Best Answer
Your configuration looks correct and i have checked your Forward and Reverse entries. That look ok. The problem is that you don't know which SPAM-System and RBL the recipient use.
So its possible that they use a special RBL-List and you are blocked on that list for example. There are a lot of possibilities but i think your configuration is ok.
Perhaps you can analyse your logs and you get some more informations.