I recently found SmarterMail is not using my outbound gateways as egress for system messages.  Instead, SmarterMail is using DNS destinations (MX or A records) and sending via the server's Internet-facing interface.  This is an inappropriate configuration for my infrastructure, and would also present issues for environments using "smart hosts" to bypass carrier restrictions, block lists, &c.

I am told the gateways are only used for assigned domains' authenticated users.  The system as a whole lacks a gateway.  This is causing my DSNs to get stuck in the outbound queue until they expire.

I propose the ability to optionally set a gateway as a "default" gateway, which would then carry all outbound system messages.