I have a farm that has servers in a DMZ and the LAN separated by a firewall. Our SMTP server is on the LAN. There are WFEs in both networks, I was wondering if there is a way to force outgoing email to be sent by only the servers on the LAN so we don't need to open another port for the WFEs to send into the LAN.
I'm not seeing anything in the outgoing email API, nor do I see a service that can be disabled. Maybe there's a timer job or some other method? Of course I'm willing to accept that it's not possible, but in that case I'm wondering how we can determine which server will send mail (round robin or some other "load balancing" method?)