I'm creating a new Exchange 2010 environment to replace the DeskNow system that my company is using currently. I don't have any experience with Exchange at all. I have the main roles installed and they appear to be working internally. AD is doing its job; I can hook up Outlook 2007 with next to no effort. I can even get to OWA. By all indications I have a working internal mail system (that nobody is using at the moment).
Now I want to be able to exchange mail with the Internets. I've been reading a few books on the subject and everyone says that I don't need an Edge Transport server - but that's as far as they go. They don't tell me how to set up Internet mail exchange without the Edge Transport server, they just go right into how to set one up and how to use it as an SMTP gateway.
So I turn to you. How does mail get to the Internet without the Edge Transport server? What goes in my DMZ? And, if everyone agrees that I need one, can it be a virtual machine or do I need an entirely new server?