The Edge Transport server role in Exchange 2007 performs a number of functions including routing messages between the Exchange organization and the internet, as well as providing Anti-virus and Anti-Spam protection. It is meant to be installed on the edge of the corporate network, or on a screened subnet. This location makes it more vulnerable than the servers on your protected network. This means you are required to do a little more work to secure the server itself. The Security Configuration Wizard in Windows Server 2003 SP1 is an ideal tool to use to reduce the attack surface of your Edge Transport server(s).
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