How to confîgure SMTP server to send incoming faxes to e-mail?

I need to set up SMTP server config (domain, port, login and password) to send incoming faxes.
Could you help me doing this?

I find easiest way to do this is through Webmin,
Install it and then go to Server -> Postfix Mail Server, and just edit the General Settings in there.
( Domain to use in Outbound Mail - tick last box and add FQDN )
( Add Relayhost )
You should be able to do any other auth stuff in there as well.
Hope this helps.