Always On VPN with Azure Gateway

Always On VPN with Azure GatewayRecently I wrote about VPN server deployment options for Windows 10 Always On VPN in Azure. In that post I indicated the native Azure VPN gateway could be used to support Always On VPN connections using Internet Key Exchange version 2 (IKEv2) and Secure Socket Tunneling Protocol (SSTP). In this post I’ll outline the requirements and configuration steps for implementing this solution.

Requirements

To support Always On VPN, point-to-site VPN connections must be enabled on the Azure VPN gateway. Not all Azure VPN gateways are alike, and point-to-site connections are not supported in all scenarios. For Always On VPN, the Azure VPN gateway must meet the following requirements.

VPN SKU

The Azure VPN gateway SKU must be VpnGw1, VpnGw2, VpnGw3, VpnGw1AZ, VpnGw2AZ, or VpnGw3AZ. The Basic SKU is not supported.

VPN Type

The VPN type must be route-based. Policy-based VPN gateways are not supported for point-to-site VPN connections.

Limitations

Using the Azure VPN gateway for Always On VPN may not be ideal in all scenarios. The following limitations should be considered thoroughly before choosing the Azure VPN gateway for Always On VPN.

Device Tunnel

RADIUS/EAP authentication for user tunnel connections is not supported if the Azure VPN gateway is configured to support device tunnel with machine certificate authentication.

Maximum Connections

A maximum of 250, 500, and 1000 concurrent IKEv2 connections are supported when using the VpnGw1/AZ, VpnGw2/AZ, and VpnGw3/AZ SKUs, respectively (x2 for active/active gateway deployments). In addition, a maximum of 128 concurrent SSTP connections are supported for all VPN gateway SKUs (x2 for active/active gateway deployments).

Always On VPN with Azure Gateway

Reference: https://docs.microsoft.com/en-us/azure/vpn-gateway/vpn-gateway-about-vpngateways#gwsku

RADIUS Requirements

To support Always On VPN connections, the Azure VPN gateway must be configured to authenticate to a RADIUS server. The RADIUS server must be reachable from the VPN gateway subnet. The RADIUS server can be hosted in Azure or on-premises. Before proceeding, ensure that any network routes, firewall rules, and site-to-site VPN tunnel configuration is in place to allow this communication.

RADIUS Configuration

Guidance for configuring Windows Server NPS for Always On VPN can be found here. The only difference when configuring NPS for use with Azure VPN gateway is the RADIUS client configuration.

Open the NPS management console (nps.msc) and follow the steps below to configure Windows Server NPS to support Always On VPN client connections from the Azure VPN gateway.

1. Expand RADIUS Clients and Servers.
2. Right-click RADIUS Clients and choose New.
3. Enter a descriptive name in the Friendly name field.
4. Enter the Azure VPN gateway subnet using CIDR notation in the Address (IP or DNS) field. The gateway subnet can be found by viewing the properties of the Azure VPN gateway in the Azure portal.
5. Enter the shared secret to be used for RADIUS communication in the Shared secret field.

Always On VPN with Azure Gateway

Azure VPN Gateway Configuration

To begin, provision a Virtual Network Gateway in Azure that meets the requirements outlined above. Guidance for implementing an Azure VPN gateway can be found here. Once complete, follow the steps below to enable support for Always On VPN client connections.

Enable Point-to-Site

Perform the following steps to enable point-to-site VPN connectivity.

1. In the navigation pane of the Azure VPN gateway settings click Point-to-site configuration.
2. Click Configure Now and specify an IPv4 address pool to be assigned to VPN clients. This IP address pool must be unique in the organization and must not overlap with any IP address ranges defined in the Azure virtual network.
3. From the Tunnel type drop-down list select IKEv2 and SSTP (SSL).
4. In the RADIUS authentication field enter the IPv4 address of the RADIUS server. At the time of this writing only a single IPv4 address is supported. If RADIUS redundancy is required, consider creating a load balanced NPS cluster.
5. In the Server secret field enter the RADIUS shared secret.
6. Click Save to save the configuration.

Always On VPN with Azure Gateway

VPN Client Configuration

Perform the following steps to configure a Windows 10 VPN client to connect to the Azure VPN gateway.

Download VPN Configuration

1. Click Point-to-site configuration.
2. Click Download VPN client.
3. Select EAPMSCHAv2 (yes, that’s correct even if EAP-TLS will be used!)
4. Click Download.
5. Open the downloaded zip file and extract the VpnSettings.XML file from the Generic folder.
6. Copy the FQDN in the VpnServer element in VpnSettings.XML. This is the FQDN that will be used in the template VPN connection and later in ProfileXML.

Always On VPN with Azure Gateway

Create a Test VPN Connection

On a Windows 10 device create a test VPN profile using the VPN server address copied previously. Configure EAP settings to match those configured on the NPS server and test connectivity.

Create an Always On VPN Connection

Once the VPN has been validated using the test profile created previously, the VPN server and EAP configuration from the test profile can be used to create the Always On VPN profile for publishing using Intune, SCCM, or PowerShell.

IKEv2 Security Configuration

The default IKEv2 security parameters used by the Azure VPN gateway are better than Windows Server, but the administrator will notice that a weak DH key (1024 bit) is used in phase 1 negotiation.

Always On VPN with Azure Gateway

Use the following PowerShell commands to update the default IKEv2 security parameters to recommended baseline defaults, including 2048-bit keys (DH group 14) and AES-128 for improved performance.

Connect-AzAccount
Select-AzSubscription -SubscriptionName [Azure Subscription Name]

$Gateway = [Gateway Name]
$ResourceGroup = [Resource Group Name]

$IPsecPolicy = New-AzVpnClientIpsecParameter -IpsecEncryption AES128 -IpsecIntegrity SHA256 -SALifeTime 28800 -SADataSize 102400000 -IkeEncryption AES128 -IkeIntegrity SHA256 -DhGroup DHGroup14 -PfsGroup PFS14

Set-AzVpnClientIpsecParameter -VirtualNetworkGatewayName $Gateway -ResourceGroupName $ResourceGroup -VpnClientIPsecParameter $IPsecPolicy

Note: Be sure to update the cryptography settings on the test VPN connection and in ProfileXML for Always On VPN connections to match the new VPN gateway settings. Failing to do so will result in an IPsec policy mismatch error.

Additional Information

Microsoft Azure VPN Gateway Overview

About Microsoft Azure Point-to-Site VPN

Windows 10 Always On VPN IKEv2 Security Configuration

 

 

 

Renew DirectAccess Self-Signed Certificates

Renew DirectAccess Self-Signed CertificatesImportant! Updated April 29, 2020 to resolve an issue where the DirectAccess RADIUS encryption certificate was not published to the DirectAccess Server Settings GPO in Active Directory.

When DirectAccess is deployed using the Getting Started Wizard (GSW), sometimes referred to as the “simplified deployment” method, self-signed certificates are created during the installation and used for the IP-HTTPS IPv6 transition technology, the Network Location Server (NLS), and for RADIUS secret encryption. Administrators may also selectively choose to use self-signed certificates for IP-HTTPS, or when collocating the NLS on the DirectAccess server. The RADIUS encryption certificate is always self-signed.

Renew DirectAccess Self-Signed Certificates

Certificate Expiration

These self-signed certificates expire 5 years after they are created, which means many DirectAccess administrators who have used this deployment option will need to renew these certificates at some point in the future. Unfortunately, there’s no published guidance from Microsoft on how to accomplish this. However, the process is simple enough using PowerShell and the New-SelfSignedCertificate cmdlet.

PowerShell Script on GitHub

The PowerShell script to renew DirectAccess self-signed certificates has been published on GitHub. You can download Renew-DaSelfSignedCertificates.ps1 here.

Important Considerations

When the IP-HTTPS certificate is renewed using this script, DirectAccess clients outside will be immediately disconnected and will be unable to reconnect until they update group policy. This will require connecting to the internal network locally or remotely using another VPN solution. The NLS and RADIUS encryption certificates can be updated without impacting remote users.

In addition, internal clients that are not online when this change is made will be unable to access internal resources by name until they update group policy. If this happens, delete the Name Resolution Policy Table (NRPT) on the client using the following PowerShell command and reboot to restore connectivity.

Get-Item -Path “HKLM:\SOFTWARE\Policies\Microsoft\Windows NT\DNSClient\DnsPolicyConfig” | Remove-Item -Confirm:$false

Additional Information

PowerShell Recommended Reading for DirectAccess Administrators

Top 5 DirectAccess Troubleshooting PowerShell Commands

 

 

NetMotion Mobility Device Tunnel Configuration

NetMotion Mobility Device Tunnel ConfigurationIn its default configuration, NetMotion Mobility connections are established at the user level. In most cases this level of access is sufficient, but there are some common uses cases that require VPN connectivity before the user logs on. Examples include provisioning a new device to a user who has never logged on before, or to allow support engineers to connect to a remote device without requiring a user to log in first.

Infrastructure Requirements

To support NetMotion Mobility’s “unattended mode” (device tunnel) it will be necessary to deploy a Windows Server 2016 (or 2012R2) Network Policy Server (NPS). In addition, an internal private certification authority (CA) will be required to issue certificates to the NPS server and all NetMotion Mobility client computers.

Client Certificate Requirements

A certificate with the Client Authentication Enhanced Key Usage (EKU) must be provisioned to the local computer certificate store on all NetMotion Mobility clients that require a device tunnel (figure 1). The subject name on the certificate must match the fully qualified domain name of the client computer (figure 2). It is recommended that certificate auto enrollment be used to streamline the provisioning process.

NetMotion Mobility Device Tunnel Configuration

Figure 1. Computer certificate with Client Authentication EKU.

NetMotion Mobility Device Tunnel Configuration

Figure 2. Computer certificate with subject name matching the client computer’s hostname.

NPS Server Certificate Requirements

A certificate with the Server Authentication EKU must be provisioned to the local computer certificate store on the NPS server (figure 3). The subject name on the certificate must match the fully qualified domain name of the NPS server (figure 4).

NetMotion Mobility Device Tunnel Configuration

Figure 3. Computer certificate with Server Authentication EKU.

NetMotion Mobility Device Tunnel Configuration

Figure 4. Computer certificate with subject name matching the NPS server’s hostname.

NPS Server Configuration

Next install the NPS server role by running the following PowerShell command.

Install-WindowsFeature NPAS -IncludeMamagementTools

Once complete, open the NPS server management console and perform the following steps.

Note: Below is a highly simplified NPS configuration designed for a single use case. It is provided for demonstration purposes only. The NPS server may be used by more than one network access server (NAS) so the example policies included below may not work in every deployment.

  1. Expand RADIUS Clients and Servers.
  2. Right-click RADIUS clients and choose New.
  3. Select the option to Enable this RADIUS client.
  4. Enter a friendly name.
  5. Enter the IP address or hostname of the NetMotion gateway server.
  6. Click Verify to validate the hostname or IP address.
  7. Select Manual to enter a shared secret, or select Generate to create one automatically.
  8. Copy the shared secret as it will be required when configure the NetMotion Mobility gateway server later.
  9. Click OK.
    NetMotion Mobility Device Tunnel Configuration
  10. Expand Policies.
  11. Right-click Network Policies and choose New.
  12. Enter a descriptive name for the new policy.
  13. Select Type of network access server and choose Unspecified.
  14. Click Next.
    NetMotion Mobility Device Tunnel Configuration
  15. Click Add.
  16. Select Client IPv4 Address.
  17. Click Add.
  18. Enter the internal IPv4 address of the NetMotion Mobility gateway server.
  19. Click OK.
  20. Click Next.
    NetMotion Mobility Device Tunnel Configuration
  21. Select Access granted.
  22. Click Next.
    NetMotion Mobility Device Tunnel Configuration
  23. Click Add.
  24. Choose Microsoft: Protected EAP (PEAP).
  25. Click OK.
  26. Select Microsoft: Protected EAP (PEAP).
  27. Click Edit.
  28. Choose the appropriate certificate in the Certificate issued to drop down list.
  29. Select Secure password (EAP-MSCHAP v2).
  30. Click Remove.
  31. Click Add.
  32. Choose Smart Card or other certificate.
  33. Click OK.
  34. Select Smart Card or other certificate.
  35. Click Edit.
  36. Choose the appropriate certificate in the Certificate issued to drop down list.
  37. Click OK.
    NetMotion Mobility Device Tunnel Configuration
  38. Uncheck all options beneath Less secure authentication methods.
  39. Click Next three times.
  40. Click Finish.
    NetMotion Mobility Device Tunnel Configuration

Mobility Server Configuration

Open the NetMotion Mobility management console and perform the following steps.

  1. In the drop-down menu click Configure.
  2. Click Authentication Settings.
  3. Click New.
  4. Enter a descriptive name for the new authentication profile.
  5. Click OK.
  6. Expand Authentication.
  7. Select Mode.
  8. Select Unattended Mode Authentication Setting Override.
  9. From the Authentication mode drop-down box choose Unattended.
  10. Click Apply.
    NetMotion Mobility Device Tunnel Configuration
  11. Expand RADIUS: Device Authentication.
  12. Select Servers.
  13. Select [Profile Name] Authentication Setting Override.
  14. Click Add.
  15. Enter the IP address of the NPS server.
  16. Enter the port (default is 1812).
  17. Enter the shared secret.
  18. Click OK.
    NetMotion Mobility Device Tunnel Configuration
  19. In the drop-down menu click Configure.
  20. Click Client Settings.
  21. Expand Device Settings.
  22. Select the device group to enable unattended mode for.
  23. Expand Authentication.
  24. Select Settings Profile.
  25. Select [Device Group Name] Group Settings Override.
  26. In the Profile drop-down menu choose the authentication profile created previously.
  27. Click Apply.
    NetMotion Mobility Device Tunnel Configuration

Validation Testing

If everything is configured correctly, the NetMotion Mobility client will now indicate that the user and the device have been authenticated.

NetMotion Mobility Device Tunnel Configuration

Summary

Enabling unattended mode with NetMotion Mobility provides feature parity with DirectAccess machine tunnel and Windows 10 Always On VPN device tunnel. It ensures that domain connectivity is available before the user logs on. This allows users to log on remotely without cached credentials. It also allows administrators to continue working seamlessly on a remote computer after a reboot without having a user present to log on.

Additional Resources

NetMotion Mobility as an Alternative to DirectAccess

 

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