Domain non authoritativ

[T-Doschke]

if stalward uses a directory for lookup recipient, then the address is checked and ok.
but if you want stalwart as non authoritative mailsystem there is no option.
Domains need a flag if the domain is autoritativ or not.
in case its authoritativ every rcpt to must have a mailbox in stalwart.
in case of non authoritativ stalwart gets the mail and forwards its to next hop.
so in non authritytive domain mode there must be a value for next hop (remote host) like SMTP outbound routing
where you name a remote host.

this way you can connect one stalwart as a front end mailsystem and relay to inner mailservers.
Can use all the sieve and checking function, like spam filter on that front end system, but having no or little mailboxes on that server itself.
Can be enhanced with a decision like routing where you can make choices of what remote host should be used (insted of a fix one use conditions to choice from different) may be a sieve script or pipling or MTA hook or only conditions like all the others.

[mdecimus]

Adding an authoritative flag is beyond the scope of the project, as such a flag won't be supported by most external directories (such as LDAP). However, you can modify the next-hop, relay, and directory expressions to implement the custom functionality you need for non-authoritative handling and routing.