Use SMTP Email server to send Emails from Business process - Without setting up a mailbox

Hi

We have a use case where we need to send outgoing Emails from business processes through an generic SMTP Email server (Not an email service provider like Office365 etc). We have the IP , port number and service credentials of the SMTP server. Find below a few questions we would like get clarity on - 



1. We understand that the typical way would be to add the SMTP Server in the Email providers lookup, create a mailbox for a valid Email account attached to the Email server and use it in the Email process element in the Business process designer. We suspect that the SMTP server we are dealing with is a generic one setup on the client's premises and not that of an actual Email service provider like Office365. Is there a way to send Emails through this SMTP server without having to explicitly create a mailbox for it?



2. We notice a few System variables related to SMTP like 'SMTP Login' , 'SMTP Username' etc. Where are they used and what are they meant for? Can these be used to send outgoing Emails through SMTP without explicitly creating a mailbox?



Greatly appreciate any help here!



Regards

Shrikanth