How To Recieve Mail On IIS

I have set up SMTP server on IIS6 (win2003) and it sends mail basically OK.

If I reply to the mail or send a mail to the domain of that server, I get an error like this:

Delivery to the following recipient failed permanently:

john@domain.com

Technical details of permanent failure:
TEMP_FAILURE: Could not initiate SMTP conversation with any hosts:
[domain.com (1): Connection timed out]

So clearly I now need to set up the server to receive mail - what are the steps required to do this?