I’m excited to announce the launch of a brand-new Discord channel dedicated to administrators working with Always On VPN! Whether you’re a seasoned pro or just getting started, this community is designed to be your go-to hub for collaboration, troubleshooting, and staying up to date on all things Always On VPN. The channel was established by my good friend Leo D’Arcy, the creator of the popular Always On VPN Dynamic Profile Generator (DPC) software.
Why Discord?
Always On VPN is a powerful solution for secure, seamless remote connectivity, but managing it comes with its own set of challenges. From configuration quirks to deployment strategies, administrators often need a space to share insights, ask questions, and learn from one another in real time. That’s where our new Discord channel comes in.
Community Forum
Discord offers a dynamic, user-friendly platform for instant communication and community building. Unlike forums or email threads, it’s a place where you can start a conversation, jump into live discussions, share resources, ask questions, share important insights or experiences, and much more.
Channels
Today, the Always On VPN Discord channel is part of the Microsoft Remote Access User Group Discord Server. It consists of multiple channels divided into the following topics.
General – This is a great place to introduce yourself and say hello to everyone!
DPC-Development – Here, you can ask questions about DPC, provide feedback, and suggest new features and functionality.
DPC-Chat – This channel is for administrators to discuss all things DPC, including deployment strategies, operation, support, and more.
Aovpn-Chat – If you’ve deployed Always On VPN but aren’t using DPC, this is your channel! Although DPC is fantastic, not everyone is using it. In this channel, you can submit questions and share general information about Always On VPN.
DirectAccess-Chat – Yes, we realize some of you are still running DirectAccess, so there’s also a channel for you! Feel free to drop in and ask questions here, hopefully about migrating soon. 😉
Who Is This For?
This channel is open to anyone managing Microsoft secure remote access products. Whether you’re an IT administrator in a small business, an enterprise network engineer, or a consultant helping clients stay connected. If you’re working with Microsoft remote access technologies, this is the place to be!
Why Not Reddit?
Funny story: I tried to create an Always On VPN subreddit a few years ago. It lasted one day before it was banned! No reason was given, and I couldn’t get anyone from Reddit to respond. I answer questions ad hoc on Reddit all the time, but there’s no dedicated space for Always On VPN or Microsoft remote access in general.
Explore the other channels, ask questions, give feedback, and share your expertise!
See You There!
Leo and I, along with many other experienced Always On VPN administrators, are on the forums daily. We encourage you to share your expertise, ask questions, and help others along the way. The more we contribute, the stronger this resource becomes for everyone. Join us today!
Recently, I wrote about Microsoft Always On VPN and Entra Conditional Access and how conditional access improves your organization’s security posture by making policy-based access decisions based on various signals such as user identity, location, device compliance, platform, sign-in risk, and more. In this post, I’ll provide step-by-step instructions for integrating Entra Conditional Access with existing Always On VPN deployments.
Requirements
To use Microsoft Entra Conditional Access with Always On VPN you must have Entra ID P1 at a minimum. To use advanced features such as risk-based policy assessment, you must have Entra ID P2. In addition, all endpoints must be under Intune management; either native Entra ID joined, or hybrid Entra ID joined.
Enable VPN Support
To begin, open the Microsoft Entra admin center (https://entra.microsoft.com/), navigate to Identity > Protection > Conditional Access, and perform the following steps.
Click VPN Connectivity.
Click New certificate.
From the Select duration drop-down list, choose an appropriate certificate validity period.
Click Create.
Once complete, click Download certificate and copy the certificate file to a domain-joined system on-premises.
Publish Certificate
Next, administrators must publish the Entra VPN root certificate in Active Directory to support domain authentication. Open an elevated PowerShell or command window and run the following commands.
certutil.exe -dspublish -f <path to certificate file> RootCA
certutil.exe -dspublish -f <path to certificate file> NtAuthCA
Note: You must be a domain administrator to perform this task.
Conditional Access Policy
Navigate to Identity > Protection > Conditional Access and click Policies, then perform the following steps to create a conditional access policy for VPN access.
Click New Policy.
Enter a descriptive name for the new policy.
Click the link in the Target resources section.
From the Select what this policy applies to drop-down list, select Resources (formerly cloud apps).
In the Include section, choose Select resources.
Click the link in the Select section.
Enter VPN in the search field.
Check the box next to VPN Server.
Click Select.
Click the link in the Grant section.
Select Grant access.
Check the box next to Require device to be marked as compliant.
Click Select.
On the Enable policy slider, select On.
Click Create.
NPS
Changes to Network Policy Server (NPS) policy and configuration are required to support Always On VPN with Entra Conditional Access.
NPS Policy
To update the Always On VPN network policy to support Entra Conditional Access, open the NPS management console (nps.msc), expand Policies, then select Network Policies and perform the following steps.
Right-click on the Always On VPN policy and choose Properties.
Select the Settings tab.
Select Vendor Specific in the RADIUS Attributes section.
Click Add.
Select the Allowed-Certificate-OID attribute.
Click Add.
Click Add.
Enter 1.3.6.1.4.1.311.87 in the Attribute value field.
Click Ok.
Click Ok.
Click Close.
Click Ok.
Important Note: This change will block new Always On VPN user tunnel connections until you update the client configuration. When integrating an existing Always On VPN implementation with Entra Conditional Access, consider creating a new NPS policy and corresponding security group to migrate users to conditional access seamlessly.
NPS Configuration
By default, NPS will perform revocation checks for certificates used for domain authentication. However, Entra Conditional Access uses short-lived certificates (one-hour lifetime) that do not include CRL Distribution Point (CDP) information. Therefore, administrators must change the NPS server configuration to disable revocation checking for certificates lacking this information.
To do this, open the registry editor (regedit.exe) and create a new registry key with the following settings.
Once complete, the server must be rebooted for the change to take effect.
Client Configuration
After making all required changes to the supporting infrastructure, you must also update the Always On VPN client configuration to leverage Entra Conditional Access. Changes to client configuration vary depending on the method used to deploy and manage Always On VPN client configuration settings.
Intune
When using Microsoft Intune and the native VPN policy type to deploy and manage Always On VPN client configuration settings, perform the following steps to update the VPN configuration to include Entra Conditional Access support.
Click Enable next to Conditional access for this VPN connection.
Click Enable next to Single sign-on (SSO) with alternate certificate.
Enter Client Authentication in the Name field.
Enter 1.3.6.1.5.5.7.3.2 in the Object Identifier field.
Enter the organization’s root certification authority (CA) certificate thumbprint in the Issuer hash field.
XML
When using a custom XML configuration file for Always On VPN client configuration settings deployed using Intune or PowerShell, edit the XML file, remove the existing <TLSExtensions></TLSExtensions> section, and replace it with the following.
In addition, add the following code between the <VPNProfile></VPNProfile> tags after <TrustedNetworkDetection>.
Note: You will find a sample XML configuration file you can copy and paste from on GitHub here.
DPC
When using Always On VPN Dynamic Profile Configurator (DPC) for managing Always On VPN client configuration settings, open the DPC group policy and navigate to Computer Configuration > Policies > Administrative Templates > DPC Client > User Tunnel Settings > Advanced and perform the following steps.
Following the guidance in this post to integrate Entra Conditional Access with Always On VPN can significantly improve your organization’s security posture. In the example above, the conditional access policy is a basic one. Yet, it dramatically reduces the attack surface for your remote access infrastructure by ensuring only compliant devices can establish a VPN connection.
Administrators can use advanced conditional access policy settings to strengthen the VPN’s security further by performing additional checks, such as requiring strong, phishing-resistant credentials and requesting multifactor authentication (MFA) for risky sign-ins.
Microsoft introduced changes to Windows domain controllers in the February 2025 security update that may result in authentication failures for Always On VPN user tunnel connections. If you suddenly find that all your Always On VPN user tunnel connections fail, additional changes may be required to resolve the issue.
Authentication Failure
Administrators may find that Always On VPN connections fail after applying the February 2025 Microsoft security updates. Specifically, users may receive the following warning message.
“The remote access connection completed, but authentication failed because the certificate that authenticates the client to the server is not valid. Ensure that the certificate used for authentication is valid.”
Error 853
Administrators will also find a corresponding event log entry with event ID 20227 from the RasClient source with the following error message.
“The user <username> dialed a connection named <connection name> which has failed. The error code returned on failure is 853.”
NPS Events
The event log on the NPS server will also record event ID 6273 from the Microsoft Windows security auditing source with the following error message.
“Network Policy Server denied access to a user.”
The authentication details of the event include Reason Code 16 with the following reason.
“Authentication failed due to a user credentials mismatch. Either the user name provided does not map to an existing user account or the password was incorrect.”
DC Events
If the issue is related to changes implemented to domain controllers in the February 2025 security update, administrators will also find a corresponding event log entry on a domain controller with event ID 39 from the Kerberos-Key-Distribution-Center source with the following error message.
“The Key Distribution Center (KDC) encountered a user certificate that was valid but could not be mapped to a user in a secure way (such as via explicit mapping, key trust mapping, or a SID). Such certificates should either be replaced or mapped directly to the user via explicit mapping.”
Root Cause
The above conditions indicate that a user attempted to authenticate to the VPN with a certificate that was not strongly mapped. Most likely, the certificate was issued using Microsoft Intune with SCEP or PKCS. This results from changes made to domain controllers in the February 2025 security update that requires certificates used for Active Directory authentication to be strongly mapped. Until now, domain controllers allowed access and only logged an event in the event log when a certificate did not include strong certificate mapping. The February 2025 security update now enforces strong certificate mapping, and authentication requests will fail without it.
Resolution
Administrators must issue new certificates that are strongly mapped to resolve this issue. For certificates issued with PKCS, changes are required on the Intune Certificate Connector server before re-issuing. For certificates issued with SCEP, changes to the device configuration policy are required. See the post Strong Certificate Mapping for Intune PKCS and SCEP Certificates for more details.
Workaround
Re-issuing certificates takes time. To restore connectivity immediately, administrators can implement the following registry settings on all domain controllers to switch back to audit mode and allow authentication without strong certificate mapping.
I recommend deploying this setting via GPO assigned to the Domain Controllers OU. However, you can also implement this change using PowerShell if necessary.
