Nick:
> Can these be different - e.g. smtpd listens on 0.0.0.0 and [::], while
> submission listens on 127.0.0.1 and [::1]?
>
> Adding '-o inet_interfaces=loopback-only' in master.cf under the
> submission service then restarting postfix made no difference, according
> to 'ss'.
master.cf settings override main.cf settings, and main.cf settings
override built-in default settings.
You can configure Postfix receive email on any IP address, as long
as the IP address is configured (as primary or alias).
Wietse
