The Microsoft Forefront Integration Kit for Network Access Protection provides a way for two Microsoft technologies to work together: Forefront Client Security and Network Access Protection (NAP). Forefront Client Security is comprehensive anti-malware software from Microsoft that provides unified protection from viruses, spyware, and other current and emerging threats. NAP is a new feature in Windows Server® 2008 that can control network access based on a computer’s compliance with an organization's health policy. NAP uses system health validators (SHVs) to configure the policies that are used to determine if network access is granted. System health agents (SHAs) provide the information needed to make this determination.

http://technet.microsoft.com/en-us/library/cc512112.aspx

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