Christian Recktenwald:
> Hi,
>
> I have to route mail by /sender/ domain.
>
> I found out about
> sender_dependent_relayhost_maps =
> pcre:/etc/postfix/sender_dependent_relayhost_map
> with:
> /.*@domain.de$/ special-mailgw
>
> Works.
>
> But: I observed postfix falling back to the MX for "domain.de" if
> "special-mailgw" is not feasable (down, timeout, responds with
> 5xx).
The Postfix SMTP client uses the name from sender_dependent_relayhost_maps
for MX lookups (A lookups if the name is inside []).
The Postfix SMTP client will not consider other names unless your
DNS provider lies, or you made other configuration changes that
cause Postfix to consider other names (for example, smtp_fallback_relay).
If you disagree, you need to present concrete evidence.
Wietse
