The quickest thing popup in our mind is - The Edge Transport Server Role in Exchange 2007!
The Edge Transport server role is designed to be the Simple Mail Transport Protocol(SMTP) gateway server between LAN email and the Internet. To ensure security,the computer that runs the Edge Transport server role should be deployed in a perimeter network (DMZ) and should not be a member of the Active Directory forest.
How it can help? Lets go into what an EdgeTransport server provides:
- Connection, recipient, sender, and content filters
- Sender identity and sender reputation analysis
- Attachment filters
- Antivirus control (by using third-party software)- we will highly recommend Antigen.
- Because the Edge Transport server is not part of an Active Directory domain, it usesActive Directory Application Mode (ADAM) to access recipient information.
- On the Edge Transport server, you create connectors to define message-flow paths intoand out of your organization. You can define multiple Edge Transport servers to provideload balancing and high availability
Summary, although you are using Exchange 2000 or 2003, you still can benefit using Exchange 2007 - if you are not planning to full move to Exchange 2007, which we recommended.
For Exchange 2007 administrators, PLEASE TAKE NOTE that you are not be able to install other server role into Edge Transport Server Role.