System Health Validators

Updated: October 21, 2008

Applies To: Windows Server 2008, Windows Server 2008 R2

System health validators (SHVs) are server software counterparts to system health agents (SHAs). Each SHA on the client has a corresponding SHV in Network Policy Server (NPS). SHVs allow NPS to verify the statement of health (SoH) that is made by its corresponding SHA on the client computer.

SHVs contain the details of the required configuration settings on client computers. For example, the Windows Security Health Validator (WSHV) is the counterpart to the Windows Security Health Agent (WSHA) on client computers. WSHV allows you to create a policy for the way in which settings on NAP-capable client computers must be configured. If the settings on the client computer as reported in the SoH do not match the settings in the SHV on the NPS server, the client computer is not compliant with health policy.

To extend this example, if you configure the WSHV to use the setting A firewall is enabled for all network connections, the firewall software that is running on the client computer must be Windows Firewall software or other firewall software that is compatible with Windows Security Center. If the client computer is not running Windows Firewall or other firewall software that is compatible with Windows Security Center, the NAP agent on the client computer sends a SoH to NPS that reports this fact. NPS compares the SoH to the configuration of the WSHV in NPS; NPS then determines that the client computer is not compliant with health policy.

The Windows Security Health Validator (WSHV) provides the following settings that you can configure based on the requirements of your deployment.

To use the setting A firewall is enabled for all network connections, the firewall software that is running on the client computer must be Windows Firewall software or other firewall software that is compatible with Windows Security Center.

Firewall software that is not compatible with Windows Security Center cannot be managed or detected by WSHA on the client computer.

If you select A firewall is enabled for all network connections, WSHA on the client computer checks if firewall software is running on the client computer, and then takes the following actions:

  • If the client computer is not running firewall software, the client computer is restricted to a remediation network until firewall software is installed and running.

  • If the only firewall software running on the client computer is a firewall that is not compliant with Windows Security Center, WSHA reports to the Network Access Protection (NAP) service that no firewall is enabled, and the client computer is restricted to a remediation network.

ImportantImportant
If you select A firewall is enabled for all network connections and client computers are not running Windows Firewall or other Windows Security Center-compliant firewall software, client computers cannot connect to your network.

If you do not select A firewall is enabled for all network connections, WSHA on the client computer does not attempt to enable firewall software or restrict client computers to a remediation network if they are not running firewall software. Because of this, client computers that are not running firewall software are not prevented from connecting to your network.

If you select A firewall is enabled for all network connections, you enable NAP autoremediation, and WSHA on the client computer reports that no firewall is enabled, either because there is no firewall or the firewall software on the client computer is not compatible with Windows Security Center, then WSHV directs WSHA on the client computer to turn on Windows Firewall.

ImportantImportant
If autoremediation is enabled and client computers are running firewall software that is not compliant with Windows Security Center and it is not detected by WSHA, WSHA on the client computer turns on Windows Firewall on the client computer, resulting in the client computer running two different firewalls simultaneously. Any exceptions configured on the noncompliant firewall are not configured in Windows Firewall, which could cause a loss of functionality on the client computer, depending on how it is configured. For this reason, it is not recommended for client computers to run two different firewalls simultaneously.

If you select An antivirus application is on, WSHA on the client computer verifies that antivirus software is running on the client computer. If the client computer is not running antivirus software, the client computer is restricted to a remediation network until antivirus software is installed and running.

The antivirus software that is running on the client computer must be compatible with Windows Security Center. Antivirus software that is not compatible with Windows Security Center cannot be managed or detected by WSHA on the client computer. If the only antivirus software running on the client computer is an antivirus application that is not compliant with Windows Security Center, the WSHA reports to WSHV that no antivirus is enabled, and the client computer is restricted to a remediation network.

If you select Antivirus is up to date, WSHA on the client computer verifies that the antivirus definitions for your antivirus applications are the most current versions and are up-to-date.

To verify that antivirus software is running and that antivirus definitions are the most recent updates available, you must select both An antivirus application is on and Antivirus is up to date.

If you do not select An antivirus application is on, WSHA on the client computer does not attempt to detect whether client computers are running antivirus software. Because of this, client computers that are not running antivirus software are not prevented from connecting to your network.

If you do not select both An antivirus application is on and Antivirus is up to date, WSHA on the client computer does not attempt to detect whether client computers are running antivirus software with the most recent antivirus definitions. Because of this, client computers that are not running antivirus software or that are running antivirus software with out-of-date antivirus definitions are not prevented from connecting to your network.

If you select An antispyware application is on, WSHA on the client computer verifies that antispyware software is running on the client computer. If the client computer is not running antispyware software, the client computer is restricted to a remediation network until antispyware software is installed and running.

The antispyware software that is running on the client computer must be Windows Defender or other antispyware software that is compatible with Windows Security Center.

Antispyware software that is not compatible with Windows Security Center cannot be managed or detected by WSHA on the client computer. If the only antispyware software running on the client computer is an antispyware application that is not compatible with Windows Security Center, the WSHA reports to WSHV that no antispyware is enabled, and the client computer is restricted to a remediation network.

If you select Antispyware is up to date, WSHA on the client computer verifies that the antispyware definitions for your antispyware applications are the most current versions and are up-to-date.

To verify that antispyware software is running and that antispyware definitions are the most recent updates available, you must select both An antispyware application is on and Antispyware is up to date.

If you do not select An antispyware application is on, WSHA on the client computer does not attempt to detect whether client computers are running antispyware software. Because of this, client computers that are not running antispyware software are not prevented from connecting to your network.

If you do not select both An antispyware application is on and Antispyware is up to date, WSHA on the client computer does not attempt to detect whether client computers are running antispyware software with the most recent antispyware definitions. Because of this, client computers that are not running antispyware software or that are running antispyware software with out-of-date antispyware definitions are not prevented from connecting to your network.

If you select An antispyware application is on, you enable NAP autoremediation, and WSHA on the client computer reports that no antispyware is enabled, either because there is no antispyware or the antispyware software on the client computer is not compatible with Windows Security Center, then WSHV directs WSHA on the client computer to turn on Windows Defender.

ImportantImportant
If autoremediation is enabled and client computers are running antispyware software that is not compliant with Windows Security Center and the antispyware is not detected by WSHA, WSHA on the client computer turns on Windows Defender on the client computer, resulting in the client computer running two different antispyware applications simultaneously.

noteNote
You can configure autoremediation using the NAP Client Management MMC snap-in.

If you select Automatic updating is enabled, and Microsoft Update Services is not enabled on the client computer, WSHA restricts the client computer to a remediation network until Microsoft Update Services is enabled.

Microsoft Update Services is enabled when one of the following settings is selected on the client computer:

  • Install updates automatically (recommended)

  • Download updates, but let me choose whether to install them

  • Check for updates, but let me choose whether to download and install them

If you select Automatic updating is enabled, you enable NAP autoremediation, and WSHA on the client computer reports that Microsoft Update Services is not enabled, then WSHV directs WSHA on the client computer to enable Microsoft Update Services and to configure Microsoft Update Services to automatically download and install updates.

noteNote
You can configure autoremediation by using the NAP Client Management MMC snap-in.

Do not configure Security Update Protection in your WSHV policy unless client computers on your network are running Windows Update Agent. In addition, client computers that are running Windows Update Agent must be registered with a server running Windows Server Update Service (WSUS).

ImportantImportant
If these conditions are not met and you configure Security Update Protection in your WSHV policy, the policy cannot be enforced by WSHA on the client computer. Because of this, WSHA restricts client computers to a remediation network and they cannot connect to your network.

If client computers are running Windows Update Agent and are registered with a WSUS server, you can configure Security Update Protection for your WSHV policy.

In that case, if you select Enforce quarantine for missing security updates and the most recent security updates are not installed, WSHA restricts the client computer to a remediation network until the most recent software security updates are installed.

You can configure Security Update Protection with several possible values that match security severity ratings from the Microsoft Security Response Center (MSRC). These values are:

  • Critical only. If selected, client computers are required to have all security updates with an MSRC severity rating of Critical. If client computers do not have these updates, the client computer is restricted to a remediation network until the updates are downloaded and installed.

  • Important and above. This is the default setting. If selected, client computers are required to have all security updates with an MSRC severity rating of Important or Critical. If client computers do not have these updates, the client computer is restricted to a remediation network until the updates are downloaded and installed.

  • Moderate and above. If selected, client computers are required to have all security updates with an MSRC severity rating of Moderate, Important, and Critical. If client computers do not have these updates, the client computer is restricted to a remediation network until the updates are downloaded and installed.

  • Low and above. If selected, client computers are required to have all security updates with an MSRC severity rating of Low, Moderate, Important, and Critical. If client computers do not have these updates, the client computer is restricted to a remediation network until the updates are downloaded and installed.

  • All. If selected, client computers are required to have all security updates, regardless of their severity rating by the MSRC. If client computers do not have the most recent updates, the client computer is restricted to a remediation network until the updates are downloaded and installed.

After you configure the security update severity rating level, you can specify the minimum number of hours allowed since the client has checked the WSUS server for new security updates. The default value for the minimum synchronization time is 22 hours.

When a client computer first attempts to connect to a NAP-enabled network and the Security Update Protection setting is configured in the WSHV policy, WSHA determines whether to restrict the client computer to a remediation network as follows:

  • If the client checked the WSUS server for updates at an interval greater than the WSHV-configured minimum number of hours allowed between checks, the client computer is restricted to a remediation network. After the client checks for updates and downloads and installs any recent updates, the client is allowed full network access.

  • If the client checked the WSUS server for updates at an interval that is equal to or less than the WSHV-configured minimum number of hours allowed between checks, the client computer is not restricted to a remediation network.

noteNote
WSHA on the client computer only performs this check the first time that the client computer attempts to connect to the network. If the client computer remains connected to the network for longer than the configured minimum synchronization time, WSHA does not check for security updates, does not download updates, and does not restrict the client computer to a remediation network.

For autoremediation to work with the Security Update Protection setting enabled and configured in your WSHV policy, the following must be true:

  • Client computers on your network are running Windows Update Agent.

  • Client computers that are running Windows Update Agent are registered with a WSUS server.

  • Autoremediation is configured and enabled.

If these conditions are met, WSHA on the client computer checks with the WSUS server to discover the most recent security updates. If WSHA discovers that the most recent security updates of the configured MSRC severity rating are not installed on the client computer, WSHA downloads and installs the most recent security updates.

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