Matus UHLAR - fantomas:
> >> 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]
> >>
> >> The reverse DNS for that host is set (IPv4 and IPv6) and seems to work.
>
> On 21.08.21 11:08, Gerald Galster wrote:
> >In case you use the standard resolvers provided by your data center,
> >you could install a local resolver like unbound.
> >
> >/etc/resolv.conf:
> >nameserver 127.0.0.1
>
> and you should do this whenever you run spam filter and/or DNS blocklist
Strictly speaking, the remote SMTP client hostname lookup goes
through the nsswitch infrastructure (/etc/nsswitch.conf), which
usually accesses local resources before DNS. So there can be naming
inconsistencies between DNS and local files.
This is different for the Postfix SMTP client which by default uses
DNS (configured with the smtp_lookup setting).
Wietse
