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Week #7 Network Access Protection

• Overview of Network Access Protection

• How NAP Works

• Configuring NAP

• Monitoring and Troubleshooting NAP

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Network Access Protection can:

What Is Network Access Protection?

• Enforce health-requirement policies on client computers

• Ensure client computers are compliant with policies

• Offer remediation support for computers that do not meet health requirements

Network Access Protection cannot:

• Prevent authorized users with compliant computersfrom performing malicious activity

• Restrict network access for computers that are runningWindows versions previous to Windows XP SP2

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NAP Scenarios

NAP benefits the network infrastructure by verifying the health state of:

• Roaming laptops

• Desktop computers

• Visiting laptops

• Unmanaged home computers

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Method Key Points

IPsec enforcement for IPsec-protected communications

• Computer must be compliant to communicate with other compliant computers

• The strongest NAP enforcement type, and can be applied per IP address or protocol port number

802.1X enforcement for IEEE 802.1X-authenticated wired or wireless connections

• Computer must be compliant to obtain unlimited access through an 802.1X connection (authentication switch or access point)

VPN enforcement for remote access connections

• Computer must be compliant to obtain unlimited access through a RAS connection

DHCP enforcement for DHCP-based address configuration

• Computer must be compliant to receive an unlimited access IPv4 address configuration from DHCP

• This is the weakest form of NAP enforcement

NAP Enforcement Methods

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NAP Platform Architecture

Intranet

Remediation Servers

InternetNAP Health

Policy Server DHCP Server

Health Registration Authority

IEEE 802.1X

Devices

Active Directory

VPN Server

Restricted Network

NAP Client with limited access

Perimeter Network

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NAP Architecture Interactions

HRA

VPN Server

DHCP Server

IEEE 802.1X Network Access Devices

Health Requirement Server

Remediation Server

NAP Client NAP Health Policy Server

RADIUS Messages

SystemHealthUpdates

HTTP or HTTP over S

SL Messages

SystemHealth

RequirementQueries

DHCP Messages

PEAP Messages over PPPPEAP Messages over EAPOL

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NAP Client Infrastructure

NAP Client

Remediation Server 2 Remediation Server

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NAP Agent

NAP EC API

NAP EC_A NAP EC_B NAP EC_C

SHA API

SHA_1 SHA_2 SHA_3. . .

. . .

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NAP Server-Side Infrastructure

Health Requirement Server 2

Health Requirement

Server 1

NAP Administration Server

SHV API

SHV_1 SHV_2 SHV_3

. . .

NPS Service

NAP Health Policy Server

NAP ES_A NAP ES_B NAP ES_C

. . .

Windows-based NAP Enforcement Point

RADIUS

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Communication Between NAP Platform Components

NAP Health Policy

Server

Windows-based

NAP Enforcement

Point

NAP Administration Server

SHV API

SHV_1 SHV_2 SHV_2

NPS Service

RADIUS

Health Requirement

Server 1

Health Requirement

Server 2

NAP Agent

NAP EC API

NAP EC_A NAP EC_B

SHA API

SHA1 SHA2

NAP Client

Remediation Server 1

Remediation Server 2

NAP ES_B NAP ES_A

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NAP Health Policy

Server

Windows-based

NAP Enforcement

Point

NAP Administration Server

SHV API

SHV_1 SHV_2 SHV_2

NPS Service

RADIUS

Health Requirement

Server 1

Health Requirement

Server 2

NAP Agent

NAP EC API

NAP EC_A NAP EC_B

SHA API

SHA1 SHA2

NAP Client

Remediation Server 1

Remediation Server 2

NAP ES_B NAP ES_A

To validate network access based on system health, a network infrastructure must provide the following functionality:

• Health policy validation: Determines whether computers are compliant with health policy requirements

• Network access limitation: Limits access for noncompliant computers

• Automatic remediation: Provides necessary updates to allow a noncompliant computer to become compliant

• Ongoing compliance: Automatically updates compliant computers so that they adhere to ongoing changes in health policy requirements

NAP Enforcement Processes

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Intranet

Remediation Servers

InternetNAP Health

Policy Server DHCP Server

Health Registration Authority

IEEE 802.1X

Devices

Active Directory

VPN Server

Restricted Network

NAP Client with limited access

Perimeter Network

How IPsec Enforcement Works

Key Points of IPsec NAP Enforcement:

• Comprised of a health certificate server and an IPsec NAP EC

• Health certificate server issues X.509 certificates to quarantine clients when they are verified as compliant

• Certificates are then used to authenticate NAP clients when they initiate IPsec-secured communications with other NAP clients on an intranet

• IPsec Enforcement confines the communication on a network to those nodes that are considered compliant

• You can define requirements for secure communications with compliant clients on a per-IP address or a per-TCP/UDP port number basis

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Intranet

Remediation Servers

InternetNAP Health

Policy Server DHCP Server

Health Registration Authority

IEEE 802.1X

Devices

Active Directory

VPN Server

Restricted Network

NAP Client with limited access

Perimeter Network

How 802.1X Enforcement Works

Key Points of 802.1X Wired or Wireless NAP Enforcement:

• Computer must be compliant to obtain unlimited network access through an 802.1X-authenticated network connection

• Noncompliant computers are limited through a restricted-access profile that the Ethernet switch or wireless AP place on the connection

• Restricted access profiles can specify IP packet filters or a virtual LAN (VLAN) identifier (ID) that corresponds to the restricted network

• 802.1X enforcement actively monitors the health status of the connected NAP client and applies the restricted access profile to the connection if the client becomes noncompliant

802.1X enforcement consists of NPS in Windows Server 2008 and an EAPHost EC in Windows Vista, Windows XP with SP2 (with the NAP Client for Windows XP), and Windows Server 2008

802.1X enforcement consists of NPS in Windows Server 2008 and an EAPHost EC in Windows Vista, Windows XP with SP2 (with the NAP Client for Windows XP), and Windows Server 2008

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Intranet

Remediation Servers

InternetNAP Health

Policy Server DHCP Server

Health Registration Authority

IEEE 802.1X

Devices

Active Directory

VPN Server

Restricted Network

NAP Client with limited access

Perimeter Network

Key Points of VPN NAP Enforcement:

• Computer must be compliant to obtain unlimited network access through a remote access VPN connection

• Noncompliant computers have network access limited through a set of IP packet filters that are applied to the VPN connection by the VPN server

• VPN enforcement actively monitors the health status of the NAP client and applies the IP packet filters for the restricted networkto the VPN connection if the client becomes noncompliant

VPN enforcement consists of NPS in Windows Server 2008 and a VPN EC as part of the remote access client in Windows Vista, Windows XP with SP2 (with the NAP Client for Windows XP), and Windows Server 2008

VPN enforcement consists of NPS in Windows Server 2008 and a VPN EC as part of the remote access client in Windows Vista, Windows XP with SP2 (with the NAP Client for Windows XP), and Windows Server 2008

How VPN Enforcement Works

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Intranet

Remediation Servers

InternetNAP Health

Policy Server DHCP Server

Health Registration Authority

IEEE 802.1X

Devices

Active Directory

VPN Server

Restricted Network

NAP Client with limited access

Perimeter Network

Key Points of DHCP NAP Enforcement:

• Computer must be compliant to obtain an unlimited access IPv4 address configuration from a DHCP server

• Noncompliant computers have network access limited by an IPv4 address configuration that allows access only to the restricted network

• DHCP enforcement actively monitors the health status of the NAP client and renews the IPv4 address configuration for accessonly to the restricted network if the client becomes noncompliant

DHCP enforcement consist of a DHCP ES that is part of the DHCP Server service in Windows Server 2008 and a DHCP EC that is part of the DHCP Client service in Windows Vista, Windows XP with SP2 (with NAP Client for Windows XP), and Windows Server 2008

DHCP enforcement consist of a DHCP ES that is part of the DHCP Server service in Windows Server 2008 and a DHCP EC that is part of the DHCP Client service in Windows Vista, Windows XP with SP2 (with NAP Client for Windows XP), and Windows Server 2008

How DHCP Enforcement Works

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What Are System Health Validators?

System Health Validators are server software counterparts to system health agents System Health Validators are server software counterparts to system health agents

• Each SHA on the client has a corresponding SHV in NPS

• SHVs allow NPS to verify the statement of health made by its corresponding SHA on the client

• SHVs contain the required configuration settings on client computers

• The Windows Security SHV corresponds to the Microsoft SHA on client computers

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What Is a Health Policy?

To make use of the Windows Security Health Validator, you must configure a Health Policy and assign the SHV to it To make use of the Windows Security Health Validator, you must configure a Health Policy and assign the SHV to it

• Health policies consist of one or more SHVs and other settings that allow you to define client computer configuration requirements for NAP-capable computers that attempt to connect to your network

• You can define client health policies in NPS by adding one or more SHVs to the health policy

• NAP enforcement is accomplished by NPS on a per-network policy basis

• After you create a health policy by adding one or more SHVs to the policy, you can add the health policy to the network policy and enable NAP enforcement in the policy

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What Are Remediation Server Groups?

With NAP enforcement in place, you should specify remediation server groups so the clients have access to resources that bring noncompliant NAP-capable clients into compliance

With NAP enforcement in place, you should specify remediation server groups so the clients have access to resources that bring noncompliant NAP-capable clients into compliance

• A remediation server hosts the updates that the NAP agent can use to bring noncompliant client computers into compliance with the health policy that NPS defines

• A remediation server group is a list of servers on the restricted network that noncompliant NAP clients can access for software updates

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NAP Client Configuration

• Some NAP deployments that use Windows Security Health Validator require that you enable Security Center

• The Network Access Protection service is required when you deploy NAP to NAP-capable client computers

• You also must configure the NAP enforcement clients on the NAP-capable computers

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What Is NAP Tracing?

• NAP tracing identifies NAP events and records them to a log file based on the one of the following tracing levels:

• Basic

• Advanced

• Debug

• You can use tracing logs to:

• Evaluate the health and security of your network

• For troubleshooting and maintenance

• NAP tracing is disabled by default, which means that no NAP events are recorded in the trace logs

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Configuring NAP Tracing

• You can configure NAP tracing by using one of the following tools:

• The NAP Client Management console

• The Netsh command-line tool

• To enable logging functionality, you must be a member of the Local Administrators group

• Trace logs are located in the following directory: %systemroot%\tracing\nap