Hostname does not Resolve to Address

[gnulab]

Hi,


In a follow up to this thread https://forum.proxmox.com/threads/email-that-never-arrives.121945/


Here is one of the log entries from a bank whose email is rejected by Proxmox.

Sep  2 00:02:40 mg postfix/smtpd[1348882]: warning: hostname icbc.com.cn does not resolve to address 61.129.111.231
Sep  2 00:02:40 mg postfix/smtpd[1348882]: connect from unknown[61.129.111.231]
Sep  2 00:02:45 mg postfix/smtpd[1348882]: NOQUEUE: reject: RCPT from unknown[61.129.111.231]: 450 4.7.25 Client host rejected: cannot find your hostname, [61.129.111.231]; from=<webmaster@icbc.com.cn> to=<XY@WYXZ.com> proto=ESMTP helo=<icbc.com.cn>
Sep  2 00:02:47 mg postfix/smtpd[1348882]: disconnect from unknown[61.129.111.231] ehlo=1 mail=1 rcpt=0/1 quit=1 commands=3/4

The IP 61.129.111.231 resolves to bjtns2.icbc.com.cn.
The hostname icbc.com.cn points to 180.169.80.158


Would whitelist the domain or whitelist the IP solves the email rejection? Is there some sort of setting in Proxmox not to reject if hostname does not resolve to an IP address?


Thank you
Henry