Here's what I'm trying to do. I want to setup an exchange server behind the firewall. This will be no problem for my internal Clients.
Now, I also have external clients that need to use that server (using pop3 and smtp). I can just open ports 110 & 25, but that seems kind of dangerous to me. I really don't want that machine directly accessible from the net.
I know I can use a front-end/back-end topology, but I REALLY don't want to go through the cost of buying 2 licenses of exchange. Is there another way of doing this? That will secure my backend exchange box, but allow my external clients to use SMTP and pop3.
I've thought about using qmail on linux, but looks like that will only solve my SMTP relay problem. I don't see how that will allow external users to POP into the exchange box.