How can I configure an IIS computer to be a Smart Host for my Exchange Server?
It may be necessary to configure a Windows 2000 server to relay or act as a smart host for security reasons, such as in a perimeter network scenario (also known as DMZ, demilitarized zone, and screened subnet) when you do not want to have a server that participates in domain security available on the Internet or you do not need the full functionality that an Exchange server provides to do e-mail for CDO and list serve-type applications.
