Thank you Victor, you are the embodiment of truth.
> On Mon, May 22, 2023 at 08:26:19PM +0800, Tom Reed via Postfix-users > wrote: > >> 1. postfix is a backup MX for foo.com >> 2. this postfix uses other MTA as relay_host > > This would be a misconfiguration. A backup MX host MUST NOT be an > effective null client that relays *all* non-local mail to a "smarthost" > relay. Rather, a backup MX host MUST be at least smart enough to > relay mail for the domain(s) in question to better (lower) preference > MX hosts. > > The best way to do this, is to configure an explicit nexthop in > default_transport, and be sure to leave relayhost empty. > > main.cf: > # MUST be empty, to avoid backup MX domain loops. > relayhost = > relay_domains = foo.com > > # Regularly updated list of valid foo.com (and any other relay > # domain) recipients: > relay_recipient_maps = ... > > # Replace "smarthost.example" with actual default relayhost. > default_transport = smtp:smarthost.example > > Relay domains will use "relay_transport" (default "relay", which is > a clone of "smtp"), so will not in error use the smarhost. > > -- > Viktor. > _______________________________________________ > Postfix-users mailing list -- postfix-users@postfix.org > To unsubscribe send an email to postfix-users-le...@postfix.org > -- sent from https://dkinbox.com/ _______________________________________________ Postfix-users mailing list -- postfix-users@postfix.org To unsubscribe send an email to postfix-users-le...@postfix.org
