Renew DirectAccess Self-Signed Certificates

Renew DirectAccess Self-Signed CertificatesWhen 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.

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

Open an elevated PowerShell command window and run the following commands to renew the DirectAccess self-signed certificates.

# // Clone and install IP-HTTPS certificate

$iphttpscert = (Get-ChildItem -Path Cert:\LocalMachine\My\ | Where-Object Thumbprint -eq ((Get-RemoteAccess).SslCertificate | Select-Object -ExpandProperty Thumbprint))
$newcert = New-SelfSignedCertificate -CloneCert $iphttpscert -FriendlyName “DirectAccess-IPHTTPS” | Select-Object -ExpandProperty Thumbprint
$cert = (Get-ChildItem -Path Cert:\LocalMachine\My\ | Where-Object Thumbprint -eq $newcert)
Set-RemoteAccess -SslCertificate $cert -PassThru

# // Clone and install NLS certificate

$nlscert = (Get-ChildItem -Path Cert:\LocalMachine\My\ | Where-Object Thumbprint -eq ((Get-RemoteAccess).NlsCertificate | Select-Object -ExpandProperty Thumbprint))
$newcert = New-SelfSignedCertificate -CloneCert $nlscert -FriendlyName “DirectAccess-NLS” | Select-Object -ExpandProperty Thumbprint
$cert = (Get-ChildItem -Path Cert:\LocalMachine\My\ | Where-Object Thumbprint -eq $newcert)
Set-DANetworkLocationServer -NLSOnDAServer -Certificate $cert

# // Clone RADIUS encryption certificate

$cert = (Get-ChildItem -Path Cert:\LocalMachine\My\ | Where-Object Subject -like “*radius-encrypt*”)
New-SelfSignedCertificate -CloneCert $cert -FriendlyName “Certificate issued by Remote Access for RADIUS shared secrets”

Script on GitHub

I’ve also published this script on GitHub. You can download Renew-DaSelfSignedCertificates.ps1 here.

Important Considerations

When the script above is executed, 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. 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

Always On VPN and Azure MFA ESTS Token Error

Always On VPN and Azure MFA ESTS Token ErrorConfiguring Multifactor Authentication (MFA) is an excellent way to ensure the highest level of assurance for Always On VPN users. Azure MFA is widely deployed and commonly integrated with Windows Server Network Policy Server (NPS) using the NPS Extension for Azure MFA. Azure MFA has a unique advantage over many other MFA providers in that it supports MFA when using Protected Extensible Authentication Protocol (PEAP). This makes Azure MFA the solution of choice for integrating with Windows 10 Always On VPN deployments using client certificate authentication, a recommended security configuration best practice.

NPS Configuration

Installing and configuring the NPS extension for Azure MFA is straightforward. Configuration guidance from Microsoft can be found here.

Connection Issues

After installing the NPS extension for Azure MFA, administrators may find that Always On VPN connections fail and the user is never challenged for authentication. The connection eventually times out and returns the following error message.

“A connection to the remote computer could not be established, so the port used for this connection was closed.”

Always On VPN and Azure MFA ESTS Token Error

In addition, the Application event log on the Windows 10 client contains an Event ID 20221 from the RasClient source that includes the following error message.

“The user [username] dialed a connection named [connection] which has failed. The error code returned on failure is 0.”

Always On VPN and Azure MFA ESTS Token Error

NPS Event Log

Reviewing the event logs on the NPS server reveals more information. The Security event log contains an Event ID 6274 from the Microsoft Windows security auditing source that includes the following error message.

“Network Policy Server discarded the request for a user. Contact the Network Policy Administrator for more information.”

Always On VPN and Azure MFA ESTS Token Error

ESTS Token Error

Digging deeper in the operational event log on the NPS server, the AuthZAdminCh log (Applications and Services Logs > Microsoft > AzureMfa > AuthZ) contains an Event ID 3 from the AuthZ source indicating an ESTS_TOKEN_ERROR message.

Always On VPN and Azure MFA ESTS Token Error

Troubleshooting ESTS Token Error

Follow the steps below to troubleshoot the ESTS_TOKEN_ERROR.

Prerequisites

Ensure that all prerequisites are met. Validate the user is being synced to Azure Active Directory and that it is properly licensed for Azure MFA.

Certificates

As part of the NPS extension configuration, a certificate is created on the NPS server that is uploaded to Azure Active Directory. To validate the certificate was created and uploaded correctly, follow the troubleshooting guidance found here.

Enterprise Applications

The Azure Multi-Factor Auth Client and the Azure Multi-Factor Auth Connector enterprise applications must be enabled to support the NPS extension for Azure MFA. To confirm they are enabled, open an elevated PowerShell command window on the server where the Azure AD Connector is installed and run the following PowerShell commands.

Import-Module MSOnline
Connect-MsolService

Get-MsolServicePrincipal -AppPrincipalId “981f26a1-7f43-403b-a875-f8b09b8cd720” | Select-Object DisplayName, AccountEnabled

Get-MsolServicePrincipal -AppPrincipalId “1f5530b3-261a-47a9-b357-ded261e17918” | Select-Object DisplayName, AccountEnabled

Always On VPN and Azure MFA ESTS Token Error

If either or both enterprise applications are not enabled, enable them using the following PowerShell commands.

Set-MsolServicePrincipal -AppPrincipalId “981f26a1-7f43-403b-a875-f8b09b8cd720” -AccountEnabled $True

Set-MsolServicePrincipal -AppPrincipalId “1f5530b3-261a-47a9-b357-ded261e17918” -AccountEnabled $True

Once complete, restart the IAS service on the NPS server using the following PowerShell command.

Restart-Service IAS -PassThru

Additional Information

Windows 10 Always On VPN Network Policy Server (NPS) Load Balancing Strategies

Deploy Windows 10 Always On VPN with Microsoft Intune

Windows 10 Always On VPN Hands-On Training Classes Now Available

Always On VPN LockDown Mode

Always On VPN LockDown ModeWhen an Always On VPN connection is provisioned to a Windows 10 client, there’s nothing to prevent a user from disconnecting or even deleting the connection. Some administrators have expressed concern about this, fearful that users may disable the VPN to improve performance or circumvent access controls when force tunneling is enabled. Also, administrators may wish to prevent users from accidentally or purposefully making changes to the configuration, or even deleting the connection entirely.

LockDown Mode

To address these concerns, Microsoft included a feature called LockDown mode for Always On VPN. Once enabled, the following conditions apply.

  • The LockDown VPN connection is always on.
  • The LockDown VPN connection cannot be disabled.
  • The user can’t make changes to or delete the LockDown connection.
  • No other VPN connections can exist on the client.
  • Force tunneling is enabled by default (split tunneling in LockDown mode is not supported).

Challenges with LockDown Mode

Always On VPN LockDown mode brings with it some unique challenges, however. Consider the following.

Limited Protocol Support

LockDown mode only supports IKEv2 and the native (built-in) VPN client. Third-party plug-in provider clients are not supported. IKEv2 is an excellent VPN protocol in terms of security, but operationally speaking it has some serious drawbacks.

Force Tunneling Only

LockDown mode uses force tunneling exclusively. All network traffic must go over the VPN connection. However, if the VPN connection is not available, the client will be unable to access any network resources at all, local or remote.

Captive Portal Issues

LockDown mode prevents clients from connecting to network resources from a network with a captive portal.

On-premises Connectivity

In LockDown mode all network traffic must flow over the VPN tunnel even if the client is on the internal network. This also means that if the VPN server is not reachable internally (unable to resolve public hostname, protocols/ports blocked by internal firewall, unable to route to VPN server, etc.) the client will not be able to access any internal or external network resources at all.

Deleting a LockDown VPN Connection

Deleting a LockDown VPN connection is also challenging. Administrators will find that trying to delete it using the UI or PowerShell often fails. To delete a LockDown Always On VPN connection, use psexec.exe to open an elevated PowerShell command window running in the system context using the following command.

.\psexec.exe -i -s C:\windows\system32\WindowsPowerShell\v1.0\powershell.exe

In the new elevated PowerShell window run the following commands to delete the LockDown VPN connection.

$Namespace = “root\cimv2\mdm\dmmap”
$ClassName = “MDM_VPNv2_01”

$obj = Get-CimInstance -Namespace $Namespace -ClassName $ClassName
Remove-CimInstance -CimInstance $obj

Optionally, download and run Remove-LockDownVPN.ps1 here.

Summary

While Always On VPN LockDown mode might seem like a good idea initially, its implementation is heavy-handed and practically speaking ends up causing more problems than it solves. For administrators that plan to enable this feature, carefully consider the drawbacks and limitations outlined above and their impact on supportability and the user experience.

Additional Information

Windows Always On VPN Device Tunnel Config using Microsoft Intune

Windows 10 Always On VPN Security Configuration 

Windows 10 Always On VPN Hands-On Training

Always On VPN SSTP Connects then Disconnects

Always On VPN SSTP Connects then DisconnectsWhen Always On VPN clients are configured to use the Secure Socket Tunneling Protocol (SSTP) with Windows Server Routing and Remote Access Service (RRAS), administrators may encounter a scenario in which a client can establish a VPN connection using SSTP successfully, but is then disconnected immediately. The system event log contains an entry with Event ID 6 from the RasSstp source that includes the following error message.

“The SSTP-based VPN connection to the remote access server was terminated because of a security check failure. Security settings on the remote access server do not match settings on this computer. Contact the system administrator of the remote access server and relay the following information.”

Always On VPN Connect and Disconnect with SSTP

Common Causes

The two most common causes of this issue are when SSTP is configured for SSL offload, and when a VPN client is on a network where SSL inspection is taking place.

SSTP Offload

The most common cause of this issue is when SSL offload is configured for SSTP on an external load balancer or application delivery controller (ADC). To prevent interception from a Man-in-the-Middle attack, the VPN client sends the certificate hash of the SSL certificate used when the VPN connection was established. If this information does not match what is configured on the RRAS server, the connection is assumed to be compromised and the connection is immediately dropped.

SSL Inspection

Another scenario where this issue may occur is when a VPN client is behind a network device configured to perform SSL deep-packet inspection (DPI). SSTP VPN clients will be unable to connect to the VPN server in this scenario.

Resolution

When offloading SSL to another device, the RRAS server must be configured to know which SSL certificate is being presented to remote clients. This information is stored in the following registry key.

HKLM:\SYSTEM\CurrentControlSet\Services\SstpSvc\Parameters\SHA256CertificateHash

However, this registry entry requires a binary value, which makes it a challenge to configure manually. To resolve this problem, it is recommended that the same SSL certificate installed on the load balancer/ADC also be installed on the VPN server (even though SSL will be offloaded). To do this, first import the SSL certificate and private key in to the Local Computer certificate store, then open the RRAS management console and perform the following steps.

  1. Right-click the VPN server and choose Properties.
  2. Select the Security tab.
  3. Uncheck Use HTTP in the SSL Certificate Binding section.
  4. Select the appropriate SSL certificate from the Certificate drop-down list (click View to verify).
  5. Click Apply.

This will add the correct SSL certificate information to the registry. Next, re-enable HTTP for SSL offload by performing the following steps.

  1. Check Use HTTP in the SSL Certificate Binding section.
  2. Click Apply.

PowerShell Configuration

If the SSL certificate cannot be installed on the VPN server, or to automate this configuration across multiple servers remotely, download and run the Enable-SstpOffload PowerShell script from my GitHub repository here and run the following command.

Enable-SSTPOffload -CertificateHash [SHA256 Certificate Hash of Public SSL Certificate] -Restart

For example…

Enable-SSTPOffload -CertificateHash “C3AB8FF13720E8AD9047DD39466B3C8974E592C2FA383D4A3960714CAEF0C4F2” -Restart

Additional Information

Windows 10 Always On VPN Load Balancing and SSL Offload

Windows 10 Always On VPN SSL Certificate Requirements for SSTP

Windows 10 Always On VPN Protocol Recommendations for Windows Server RRAS

Always On VPN ProfileXML Editing and Formatting with Visual Studio Code

Always On VPN ProfileXML Editing and Formatting with Visual Studio CodeWindows 10 Always On VPN is designed to be implemented and managed using a Mobile Device Management (MDM) platform such as Microsoft Intune. With Intune specifically, there is an option to configure an Always On VPN profile in the UI. However, it provides only limited support and does not include all settings and options required for many deployments. Crucially, IKEv2 advanced security settings cannot be configured using the Intune portal. Also, there is currently no option for configuring a device tunnel with Intune. In these scenarios the administrator must manually create a ProfileXML file and provision it using Intune, System Center Configuration Manager (SCCM), or PowerShell.

ProfileXML

ProfileXML includes all settings that define the Always On VPN connection. The options and settings available are documented in the VPNv2 Configuration Service Provider (CSP) reference on Microsoft’s web site. ProfileXML is formatted using elements and settings within those elements. The formatting and syntax are critical to ensuring proper operation. Any error in syntax or formatting can result in an error, such as those described here.

XML Readability

Formatting is also important for readability, which is often helpful when reviewing configuration settings or troubleshooting syntax errors. For example, an element may be defined correctly but may be nested wrong. Often XML files are created with all text being left-justified, or with everything on a single line, making the content difficult to read. Using a file editor that recognizes XML files can be beneficial.

Visual Studio Code

To create, edit, and review ProfileXML it is recommended that a proper editing tool be used. I recommend using Microsoft’s Visual Studio Code. It is free, and it is especially helpful when editing XML files. Visual Studio Code can be downloaded here.

XML Tools VS Code Plug-In

To further enhance Visual Studio Code’s XML editing and formatting capabilities I recommend installing the XML Tools plug-in. This tool extends the native features of VS code for handling XML files. One important thing it adds is a formatting feature that will make your ProfileXML much easier to manage. The XML Tools plug-in for VS Code can be downloaded here.

XML Formatting

Once the XML Tools plug-in for VS code has been installed, formatting XML for readability is straightforward. Simply right-click anywhere in the document and choose Format Document.

Always On VPN ProfileXML Editing and Formatting with Visual Studio CodeOnce complete, the XML document will be formatted with proper indenting and nesting of elements, as shown here.

Always On VPN ProfileXML Editing and Formatting with Visual Studio CodeSummary

Formatting and syntax must be strictly adhered to when creating a ProfileXML file for Windows 10 Always On VPN. Using Visual Studio Code with the XML Tools plug-in allow the administrator to create and edit XML with proper formatting, which greatly improves readability and allows for streamlined configuration review and troubleshooting.

Acknowledgements

Special thanks to Colin, an avid reader of the articles on this web site for this tip. Thanks, Colin! 🙂

Additional Information

Always On VPN and DirectAccess Scripts and Sample Files on GitHub

Always On VPN IKEv2 Security Configuration

Always On VPN Device Tunnel Step-by-Step Configuration using PowerShell

Always On VPN Hands-On Training Classes in 2019

Always On VPN Unable to Create Profile General Error

Always On VPN Unable to Create Profile General ErrorWhen configuring a Windows 10 Always On VPN profile connection using the Microsoft-provided MakeProfile.ps1 PowerShell script or my PowerShell Always On VPN deployment script, the creation of a new connection may fail and the administrator may encounter the following error message.

Unable to create [connection name] profile: A general error occurred that is not covered by a more specific error code.

Always On VPN Unable to Create Profile General Error

This error message is, of course, terribly ambiguous and provides no real actionable information for the administrator to resolve the problem with. This makes troubleshooting this error somewhat challenging.

Probable Cause

In my experience, this error message is almost always related to a syntax error in ProfileXML. For example, to generate the error message above, my XML file included the following error.

Always On VPN Unable to Create Profile General Error

In this example, the setting should be True or False. The setting “foo” is unrecognized and causes the ambiguous error message. It can also happen if mutually exclusive configuration settings are defined. For example, it can occur if the DisableClassBasedDefaultRoutes element is set to true when the RoutingPolicyType element is set to ForceTunneling.

Error Resolution

The only way to resolve this error is to ensure there are no configuration errors for any defined elements in ProfileXML. Review the file carefully for errors such as typos or elements that are out of place. Refer to the VPNv2 Configuration Service Provider (CSP) ProfileXML XSD for detailed syntax examples. In addition, I have some sample ProfileXML configuration files that can be used for reference on my GitHub page.

XML Format Validation

To ensure ProfileXML is properly formatted, it is recommended that an XML editor be used when generating or editing the configuration file. This will ensure that all defined elements are well-formed, and that all tags are properly closed. Use caution though, because some XML editors (including some popular online formatting tools) will insert XML version and encoding information at the beginning of the file. This information must be removed from ProfileXML prior to deployment.

Additional Information

Windows 10 VPNv2 Configuration Service Provider (CSP) Reference

Windows 10 VPNv2 Configuration Service Provider (CSP) ProfileXML XSD Native Profile Examples

Windows 10 Always On VPN PowerShell Scripts and Sample ProfileXML Configuration Files on GitHub

Free Online XML Formatter

Windows 10 Always On VPN Hands-On Training Classes for 2019

Always On VPN and DirectAccess Scripts and Sample Files on GitHub

Always On VPN and DirectAccess Scripts and Sample Files on GitHubIf you’re looking for specialized configuration scripts for Windows 10 Always On VPN, Windows Server Routing and Remote Access Service (RRAS), or DirectAccess then have a look at my GitHub page! There I’ve uploaded a few tools I’ve created (with the help of my good friend Jeff Hicks!) along with some sample ProfileXML files. Here’s a sample of what you’ll find there today.

Always On VPN

This repository includes PowerShell scripts and sample ProfileXML files used for configuring Windows 10 Always On VPN. These scripts have been adopted from those provided by Microsoft and modified to work with a separate XML file. These scripts can be used for local testing and for deploying Always On VPN connections using System Center Configuration Manager (SCCM). The ProfileXML files can be helpful for those administrators looking for real world configuration examples.

https://github.com/richardhicks/aovpn

SstpOffload

This repository includes a PowerShell script to enable TLS offload for Windows Server RRAS Secure Socket Tunneling Protocol (SSTP) VPN connections when the public SSL certificate can’t be installed on the RRAS server. TLS offload for SSTP can be enabled in scenarios where better security, performance, and scalability are desired.

https://github.com/richardhicks/sstpoffload

DirectAccess

This repository includes the PowerShell script Move-DaInboxAccountingDatabase which can be used to move the DirectAccess inbox accounting database files. The default location of the database files is on the C: drive, and many administrators have encountered disk space issues, especially in large scale deployments. This script will relocate the database files to the location of your choice.

https://github.com/richardhicks/directaccess

More to Come!

Be sure to check my GitHub site for more PowerShell script and sample files on a regular basis. Or better yet, give me a follow! I’ll be sure to post more as time goes on. In addition, I’ll be going through my older articles where I’ve provided PowerShell code samples and will include them in the repository too.

Standard Disclaimer

All the sample files and PowerShell scripts I’ve shared on GitHub are provided as-is. Although they’ve been thoroughly tested, I can’t be certain I’ve accommodated every deployment scenario. Please use caution when running these scripts on production machines.

Additional Information

Always On VPN Hands-On Training Classes 2019

Jeff Hicks’ Blog

Always On VPN IKEv2 Security Configuration

Always On VPN IKEv2 Security ConfigurationWhen deploying Windows 10 Always On VPN, many administrators choose the Internet Key Exchange version 2 (IKEv2) protocol to provide the highest level of security and protection for remote connections. However, many do not realize the default security parameters for IKEv2 negotiated between a Windows Server running the Routing and Remote Access Service (RRAS) and a Windows 10 VPN client are far less than ideal from a security perspective. Additional configuration on both the server and the client will be required to ensure adequate security and protection for IKEv2 VPN connections.

Windows 10 and RRAS IKEv2 Defaults

In their default configuration, a Windows 10 client connecting to a Windows Server running RRAS will negotiate an IKEv2 VPN connection using the following IPsec security parameters.

  • Encryption: 3DES
  • Authentication/Integrity: SHA-1
  • Key Size: DH Group 2 (1024 bit)

This information can be obtained by opening an elevated PowerShell command window and running the following command.

Get-NetIPsecMainModeSA | Select-Object -First 1

Always On VPN IKEv2 Security Configuration

This can also be confirmed by viewing a network trace as shown here.

Always On VPN IKEv2 Security Configuration

These IPsec security parameters might have been acceptable in the 90’s, but they certainly are not today. 🙂

Improving IKEv2 Security

To provide a baseline level of protection to meet today’s requirements for security and privacy for IKEv2 VPN connections, the following are the minimum recommended IPsec security parameters.

  • Encryption: AES128
  • Authentication/Integrity: SHA-256
  • Key Size: DH Group 14 (2048 bit)

RRAS Custom IPsec Policy

To implement these recommended security baselines for IKEv2 on a Windows Server running RRAS it will be necessary to define a custom IPsec security policy. To do this, open an elevated PowerShell command window and run the following commands on each RRAS server.

Set-VpnServerConfiguration -CustomPolicy -AuthenticationTransformConstants SHA256128 -CipherTransformConstants AES128 -DHGroup Group14 -EncryptionMethod AES128 -IntegrityCheckMethod SHA256 -PFSgroup PFS2048 -SADataSizeForRenegotiationKilobytes 102400

Restart the Remote Access Management service for the changes to take effect.

Restart-Service RemoteAccess -PassThru

Always On VPN IKEv2 Security Configuration

Windows 10 Client Settings

The IPsec policy must match on both the server and the client for an IKEv2 VPN connection to be successful. Unfortunately, none of the IKEv2 IPsec security association parameters proposed by default on Windows 10 clients use 2048-bit keys (DH Group 14), so it will be necessary to define a custom IPsec security policy on the client to match the settings configured on the server.

To configure a matching IPsec security policy on an individual Windows 10 VPN client, open an elevated PowerShell command window and run the following command.

$connection = “[connection name]”
Set-VpnConnectionIPsecConfiguration -ConnectionName $connection -AuthenticationTransformConstants SHA256128 -CipherTransformConstants AES128 -DHGroup Group14 -EncryptionMethod AES128 -IntegrityCheckMethod SHA256 -PFSgroup PFS2048 -Force

Always On VPN IKEv2 Security Configuration

Restore Defaults

In the process of testing it may be necessary to restore the default IKEv2 configuration on both the client and the server. This can be accomplished by running the following PowerShell commands.

Server – Set-VpnServerConfiguration -RevertToDefault

Client – Set-VpnConnectionIPsecConfiguration -ConnectionName [connection_name] -RevertToDefault -Force

Always On VPN XML Settings

To implement a custom IPsec policy using the minimum recommended security settings for an Always On VPN connection using IKEv2, add the following settings to your ProfileXML.

<VPNProfile>
 <NativeProfile>
  <CryptographySuite>
   <AuthenticationTransformConstants>SHA256128</AuthenticationTransformConstants>
   <CipherTransformConstants>AES128</CipherTransformConstants>
   <EncryptionMethod>AES128</EncryptionMethod>
   <IntegrityCheckMethod>SHA256</IntegrityCheckMethod>
   <DHGroup>Group14</DHGroup>
   <PfsGroup>PFS2048</PfsGroup>
  </CryptographySuite>
 </NativeProfile>
</VPNProfile>

Why Not AES 256?

In the examples above you’ll notice that I’ve chosen to use AES128 and not AES256. This is by design, as AES256 does not provide any practical additional security in most use cases. Details here.

Enhanced Security and Performance

To further improve security and performance for IKEv2, consider implementing Elliptic Curve Cryptography (EC) certificates and using Galois Counter Mode (GCM) cipher suites such as GCMAES128 for authentication and encryption.

Additional Information

Always On VPN Certificate Requirements for IKEv2

Always On VPN IKEv2 Connection Failure Error Code 800

Always On VPN IKEv2 Load Balancing with the KEMP LoadMaster Load Balancer

Always On VPN and Windows Server 2019 NPS Bug

Note: This post updated March 19,2019 to reflect new workaround configuration guidance.

When deploying a Windows Server 2019 Network Policy Server (NPS) to support a Windows 10 Always On VPN implementation, administrators may encounter the following error when attempting to establish a VPN connection on a remote Windows 10 client.

Can’t connect to [connection name].

The connection was prevented because of a policy configured on your RAS/VPN server. Specifically, the authentication method used by the server to verify your username and password may not match the authentication method configured in your connection profile. Please contact the Administrator of the RAS server and notify them of this error.

Always On VPN and Windows Server 2019 Network Policy Server Bug
In addition, an event ID 20227 from the RasClient will be recorded in the application event log with the following error message.

The user [username] dialed a connection named [connection name] which has failed. The error code returned on failure is 812.

Always On VPN and Windows Server 2019 Network Policy Server Bug

Common Causes

Always On VPN error code 812 indicates an authentication policy mismatch between the client and the server. This often occurs when, for example, the server is configured to use Protected Extensible Authentication Protocol (PEAP), but the client is configured to use Microsoft CHAP Version 2 (MS-CHAP v2).

Troubleshooting

Carefully review the authentication policy on both the client and server to ensure they match. Next, enable firewall logging on the NPS server to log both allowed and dropped packets. Attempt another VPN connection and observe the firewall logs. In this example the firewall is dropping packets inbound on UDP port 1812.

Always On VPN and Windows Server 2019 Network Policy Server Bug

Interestingly, the default Windows firewall rule allowing inbound UDP port 1812 is enabled and set to allow for all profiles.

Always On VPN and Windows Server 2019 Network Policy Server Bug

Windows Server 2019 Bug

It appears that Microsoft’s recently released Windows Server 2019 has a bug that prevents NPS from working correctly out of the box. Specifically, it looks like the default Windows firewall rules to allow inbound UDP port 1812 (RADIUS authentication) and inbound UDP port 1813 (RADIUS accounting) do not work.

Resolution

To resolve this issue, open an elevated command window and enter the following command.

sc sidtype IAS unrestricted

Once complete, restart the server and the default Windows Firewall rules for NPS traffic will work correctly.

Additional Information

Windows 10 Always On VPN NPS Load Balancing Strategies

DirectAccess IP-HTTPS Not Working Properly in Windows Server 2019

After installing and configuring DirectAccess in Windows Server 2019 you may encounter an error message indicating that IP-HTTPS is not working properly. Looking at the Operations Status overview in the Dashboard of the Remote Access Management console shows that the IP-HTTPS interface is in error.

DirectAccess IP-HTTPS Not Working Properly in Windows Server 2019

IP-HTTPS Route Error

Viewing the detailed Operations Status shows the following error message.

Error: The IP-HTTPS route does not have published property enabled.

DirectAccess IP-HTTPS Not Working Properly in Windows Server 2019

Missing Route

Looking at the routing table on the DirectAccess server reveals that a route to the client IPv6 prefix is indeed missing.

DirectAccess IP-HTTPS Not Working Properly in Windows Server 2019

Resolution

To resolve this error message, add the client IPv6 route to the DirectAccess server’s routing table and publish it. This is accomplished by running the following PowerShell commands on the DirectAccess server.

$IPv6prefix = (Get-RemoteAccess).ClientIPv6Prefix
New-NetRoute -AddressFamily IPv6 -DestinationPrefix $IPv6prefix -InterfaceAlias “Microsoft IP-HTTPS Platform Interface” -Publish Yes

Next, restart the Remote Access Management service (RaMgmtSvc) using the following PowerShell command.

Restart-Service RaMgmtSvc -PassThru

DirectAccess IP-HTTPS Not Working Properly in Windows Server 2019

Once complete, refresh the management console and the IP-HTTPS error message should be resolved and the operations status should state that it is now working properly.

DirectAccess IP-HTTPS Not Working Properly in Windows Server 2019

 

Additional Information

SSL Certificate Conisderations for DirectAccess IP-HTTPS

DirectAccess Expire IP-HTTPS Certificate and Error 0x800b0101

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