Hylafax
 

I have hylafax running and my windows clients can send faxes with no problem.

How do I set up email notification and email to fax? My email server runs on a different server and I can't find documentation for this configuration.

You can start by reading the "Email to Fax" and "Fax to Email" sections of the FAQ. You'll also need to install a mail server on the hylafax machine.