Interesting read
Source: http://www.microsoft.com/technet/itshowcase/content/edgetransport.mspx
In deploying the Exchange 2007 based messaging protection solution, Microsoft IT used all messaging protection features of the Edge Transport server role and Forefront Security for Exchange Server to block, delete, reject, or quarantine unwanted messages. To further increase security, servers were hardened and audited for vulnerabilities to ensure readiness for Internet visibility.
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Microsoft IT used the principle of multilayer, multistep messaging protection and developed a systematic approach to reducing unwanted messages. First, Microsoft IT protects internal network resources from the outside through a perimeter network. Second, Microsoft IT uses Edge Transport servers and their many filters to block as many unwanted messages as possible from entering the internal messaging environment. Third, Microsoft IT protects the internal environment by enforcing antivirus policies and enabling users to specify safe and blocked senders.
In deploying the Exchange 2007–based messaging protection solution, Microsoft IT used all messaging protection features of Edge Transport servers and Forefront Security for Exchange Server to block, delete, reject, or quarantine unwanted messages. To further increase security, servers were hardened and audited for vulnerabilities to ensure readiness for Internet visibility.
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