Question : Do I need an Exchange frontend and can I live without ISA?

Users want some kind of remote mail access. Have a D-Link DFL200 firewall with a DMZ port. A Win2k3 server is placed in DMZ and acts as Web/Ftp server. On the LAN we have a Win2k3 Exchange server.

Everything works fine.

How can I implement some kind of remote mail-access? OWA? HTTPS? RPC?
I'm a completely beginner in OWA, HTTPS, RPC so I need some step-by-step advices.

I have never used ISA so I would prefer a solution without ISA.

Do I have to install Exchange/OWA on the Web server in DMZ, or is it possible do make a secure solution against the Exchange server on the LAN. OWA works fine on the Exchange backend server for LAN users.

Answer : Do I need an Exchange frontend and can I live without ISA?

thing is, isa actually inspects the protocol and is integrated with your active directory to verify logins, assuring that the right person is actually using OWA. It's recommended to use ISA to make sure no one tries to get in through http or https.

I've used OWA both with and without ISA, but my company isn't high profile enough to get hacked I guess. I recommend using ISA, but if you don't have the budget...well, just use SSL and check logs every once in a while :) (and do the firewall access rules busbar gave you).