Hi, I am having trouble receiving mail from this specific host:
Aug 21 10:22:59 stretch postfix/smtpd[8394]: warning: hostname mail.radio-z.net does not resolve to address 136.243.54.124 Aug 21 10:22:59 stretch postfix/smtpd[8394]: connect from unknown[136.243.54.124] Aug 21 10:22:59 stretch postfix/smtpd[8394]: 18D3F6A40A2B: client=unknown[136.243.54.124] And the same error with the according IPv6 address of that host. It requires me to change my client_restrictions: reject_unknown_client_hostname -> reject_unknown_reverse_client_hostname The reverse DNS for that host is set (IPv4 and IPv6) and seems to work. When I dig mail.radio-z.net ;; ANSWER SECTION: mail.radio-z.net. 53273 IN A 136.243.54.124 I see no DNS troubles. What could be the problem with that system? Greets, Ludi
