Your network consists of one Windows Server 2008 domain. The network contains portable
computers. You configure a server that runs Windows Server 2008 as a Routing and Remote Access
Service (RRAS) server. Users connect remotely to the network through a virtual private network
(VPN) connection to the RRAS server from both company-issued portable computers and noncompany-issued computers. The relevant portion of the network is shown in the following diagram.

You need to prepare the environment to secure remote access to the network. The solution must
meet the following requirements:
Only computers that have Windows Firewall enabled can connect remotely.
Only computers that have the most up -to-date antivirus definitions can connect remotely.

Only computers that run Windows Vista and have the most up -to-date updates can connect
remotely.
What should you do?

A.
Implement Authorization Manager.

B.
Implement Network Access Protection (NAP) on the perimeter network.

C.
Install a Microsoft Internet Security and Acceleration Server (ISA) 2006 on the network.

D.
Create a domain Group Policy object (GPO). Enable Windows Firewall and publish updated
antivirus definitions in the GPO.

Explanation:
To ensure that the computers that connect to the corporate network meet all the required
conditions, you need to implement Network Access Protection (NAP) on the perimeter network. NAP
uses System Health Agent (SHA) to check if the specified system health requirements are fulfilled.
The SHA can verify whether the Windows Firewall is on; antivirus and antispyware software are
installed, enabled, and updated; Microsoft Update Services is enabled, and the most recent security
updates are installed. If the system is not in the required state, the SHA can then start a process to
remedy the situation. For example, it can enable Windows Firewall or contact a remediation server
to update the antivirus signatures
Windows Server 2008 NAP (Network Access Protection) infrastructure
http://4sysops.com/archives/windows-server-2008-nap-network-access-protection-infrastructure/