mail relay question

Hello EE,

I have IIS configured for smtp relay, i have "mydomain.ca" configured for "forward all mail to smart host" somemailer.anotherdomain.ca . So my question is , when the email is sent to the forwarder , does the forwarder receive the message and open a new transaction from the somemailer.anotherdomain.ca ? What are the steps for how the transaction occurs to the recipient email server?

For example, if the recipients mail logs show fails to end with "." on a line by itself, is this my IIS virtual smtp server or the somemailer.anotherdomain.ca forwarder?