I need exim to send all outbound email through a remote mail server

[pmjcreations]

Hello,

I am trying to work on https://help.directadmin.com/item.php?id=153

I have created two new VPS, one with Port 25 blocked and second with Port 25 opened.

I have installed DA yesterday on these two VPSs.

I assume that I need to make these changes to my primary DA server and not the secondary DA that is meant to be the router (Port 25 Opened).

I need to send every email; like the system notification emails and my customer's emails with this method.

I also need to make sure stuff like DKIM is in place so that email delivery will be better.

Let me know what would be the correct transport option here; transport = remote_smtp or transport = auth_relay?

And what exactly the route_list = * smtp.yourisp.com would be?