Always On VPN Error 13806

Troubleshooting Always On VPN Error 691 and 812 – Part 2

As a follow-up to my last post regarding Always On VPN error 13801, this post will cover a similar and related error administrators may encounter, the 13806 error. As mentioned previously, certificate configuration is crucial for Always On VPN deployments. I described some specific certificates requirements for IKEv2 in this earlier post. Following this guidance, administrators should have no issues with IKEv2 Always On VPN connections. However, it is always possible to encounter an error if any of these certificates are missing or misconfigured.

Error 13806

Much like the error 13801 described previously, 13806 is also common. When an Always On VPN connection using IKEv2 fails, the Windows Application event log will record an event ID 20227 from the RasClient source. The error message states the following:

“The user [username] dialed a connection named [connection name] which has failed. The error code returned on failure is 13806”.

IKE Failed To Find Valid Machine Certificate

Error 13806 translates to ERROR_IPSEC_IKE_NO_CERT, indicating IKE failed to find a valid machine certificate. The problem can be on the device, the VPN server, or an issue with the VPN server configuration.

Device Certificate

For the device tunnel, the most obvious cause of this error is a missing device authentication certificate on the client itself. Ensure the endpoint has a valid certificate issued by the organization’s internal PKI that includes Client Authentication EKU (OID 1.3.6.1.5.5.7.3.2). The certificate must have a subject name matching the device’s FQDN. It must also be valid (not expired), trusted, and not revoked.

Certificate Chain

A 13806 error will occur if the device certificate installed on the client is not trusted or if the client does not trust the certificate installed on the VPN server. Ensure the client has all the necessary root and intermediate certification authority (CA) certificates installed in their respective certificate stores.

VPN Server Certificate

A 13806 error can also occur if the VPN server does not have a properly configured server certificate. Ensure the VPN server has a valid certificate issued by the organization’s internal PKI that includes both the Server Authentication (OID 1.3.6.1.5.5.7.3.1) and IP security IKE intermediate (OID 1.3.6.1.5.5.8.2.2) EKUs. The subject name must match the public fully qualified domain name (FQDN) used by VPN clients to connect to the VPN server (not the server’s NetBIOS name). Again, ensure the certificate is valid (not expired), trusted, not revoked, and all necessary root and intermediate CA certificates are installed in their respective certificate stores.

Certificate Revocation

An expired Certificate Revocation List (CRL) can also result in a 13801 error. Open the Enterprise PKI console (pkiview.msc) on an issuing CA and review the status of all CRLs. If any are expired, resolve any issues preventing the CRL from publishing successfully, then issue a new CRL by running certutil.exe -crl on the issuing CA server.

RRAS Configuration

Another cause of the 13806 error for the user tunnel is a misconfigured Routing and Remote Access Service (RRAS) VPN server. An error 13806 can happen if the administrator incorrectly defines a trusted root CA using Set-VpnAuthProtocol. Ensure that the root certificate thumbprint matches exactly the root CA server’s thumbprint used to issue certificates to VPN devices and the VPN server.

Get-VpnAuthProtocol

Root CA Certificate Thumbprint

Resolution

Ensure that devices and VPN servers have correctly configured certificates installed. If the root CA certificate is assigned incorrectly on the VPN server, follow the guidelines detailed here to update the configuration.

Additional Information

Microsoft Windows Always On VPN Error 13801

Microsoft Windows Always On VPN Certificate Requirements for IKEv2

Microsoft Windows Always On VPN IPsec Root Certificate Configuration Issue

Microsoft Windows Always On VPN IKEv2 Policy Mismatch Error

Microsoft Windows Always On VPN IKEv2 Security Configuration

Microsoft Windows Always On VPN IKEv2 Fragmentation

Microsoft Windows Always On VPN IKEv2 Load Balancing and NAT

Microsoft Windows Always On VPN IKEv2 Features and Limitations

Always On VPN Error 13801

Troubleshooting Always On VPN Error 691 and 812 – Part 2

Certificate configuration is crucial for Always On VPN deployments. I described some specific certificates requirements for IKEv2 in this previous post. Following this guidance, administrators should have no issues with IKEv2 Always On VPN connections. However, it is always possible to encounter an error if any of these certificates are missing or misconfigured.

Error 13801

One of the most common errors related to IKEv2 and certificates is 13801. When an Always On VPN connection using IKEv2 fails, the Windows Application event log will record an event ID 20227 from the RasClient source. The error message states the following:

“The user [username] dialed a connection named [connection name] which has failed. The error code returned on failure is 13801”.

IKE Authentication Credentials are Unacceptable

Error 13801 translates to ERROR_IPSEC_IKE_AUTH_FAIL, indicating an authentication failure related to IPsec. The problem can be on the device, the VPN server, or an issue with the VPN server configuration.

Certificate Chain

A 13801 error will occur if the client does not trust the certificate installed on the VPN server. Ensure the client has all the necessary root and intermediate certification authority (CA) certificates installed in their respective certificate stores.

VPN Server Certificate

A 13801 error can also occur if the VPN server does not have a properly configured server certificate. Ensure the VPN server has a valid certificate issued by the organization’s internal PKI that includes both the Server Authentication (OID 1.3.6.1.5.5.7.3.1) and IP security IKE intermediate (OID 1.3.6.1.5.5.8.2.2) EKUs. The subject name must match the public fully qualified domain name (FQDN) used by VPN clients to connect to the VPN server (not the server’s NetBIOS name). Again, ensure the certificate is valid (not expired), trusted, not revoked, and all necessary root and intermediate CA certificates are installed in their respective certificate stores.

Certificate Revocation

An expired Certificate Revocation List (CRL) can also result in a 13801 error. Open the Enterprise PKI console (pkiview.msc) on an issuing CA and review the status of all CRLs. If any are expired, resolve any issues preventing the CRL from publishing successfully, then issue a new CRL by running certutil.exe -crl on the issuing CA server.

RRAS Configuration

Another cause of the 13801 error for the device tunnel is a misconfigured Routing and Remote Access Service (RRAS) VPN server. An error 13801 can happen if the administrator incorrectly defines a trusted root CA using Set-VpnAuthProtocol. Ensure that the root certificate thumbprint matches exactly the root CA server’s thumbprint used to issue certificates to VPN devices and the VPN server.

Get-VpnAuthProtocol

Root CA Certificate Thumbprint

Resolution

Ensure that devices and VPN servers have correctly configured certificates installed. If the root CA certificate is assigned incorrectly on the VPN server, follow the guidelines detailed here to update the configuration.

Additional Information

Microsoft Windows Always On VPN Error 13806

Microsoft Windows Always On VPN Certificate Requirements for IKEv2

Microsoft Windows Always On VPN IPsec Root Certificate Configuration Issue

Microsoft Windows Always On VPN IKEv2 Policy Mismatch Error

Microsoft Windows Always On VPN IKEv2 Security Configuration

Microsoft Windows Always On VPN IKEv2 Fragmentation

Microsoft Windows Always On VPN IKEv2 Load Balancing and NAT

Microsoft Windows Always On VPN IKEv2 Features and Limitations

Always On VPN and Intune Proactive Remediation

Always On VPN and Autopilot Hybrid Azure AD Join

When configuring and deploying Windows Always On VPN using Microsoft Endpoint Manager (MEM)/Intune, administrators may find that some settings are not exposed in the MEM UI. In some cases, deploying the configuration profile using custom XML is the workaround. However, many crucial Always On VPN settings are not exposed using either method. Here, administrators must resort to editing settings in the VPN configuration file on the client after provisioning the VPN profile.

Phonebook

A file called rasphone.pbk stores all Windows VPN settings on the endpoint. It includes name/value pairs that correspond to many settings administrators change manually in the GUI. Other settings can be changed using PowerShell. Depending on the connection type, the file can be found in one of two locations.

  • User Tunnel: $env:AppData\Microsoft\Network\Connections\Pbk\rasphone.pbk
  • Device Tunnel: $env:ProgramData\Microsoft\Network\Connections\Pbk\rasphone.pbk

Documentation for Windows VPN client phonebook entry settings can be found here.

Limitations

Unfortunately, editing the rasphone.pbk file isn’t always convenient. Making the changes is technically easy. Administrators can write a simple PowerShell script to update the text file as required. However, automating this at scale is challenging. Thankfully, Intune Proactive Remediations can help.

Proactive Remediations

With Intune Proactive Remediations, administrators can create and deploy script packages to monitor and optionally update specific configuration settings. The package includes two scripts, a detection script, and a remediation script. The detection script looks at the current value of a particular setting and reports on its compliance. The remediation script is triggered to update the setting if the value is incorrect.

Requirements

Intune Proactive Remediations has some specific licensing requirements. Administrators must also enroll devices into Endpoint analytics and provision a Windows Health Monitoring configuration profile. There are also limitations on the size and type of scripts that administrators can use. More information on prerequisites can be found here.

Script Packages

Administrators can create detection and remediation PowerShell scripts to update settings in rasphone.pbk, or optionally, they can download sample scripts from my GitHub repository here. This repository contains user and device tunnel detection and remediation scripts for many popular settings in rasphone.pbk. Examples include updating the VPN Strategy, changing VPN interface metrics, disabling class-based default routes, and many more.

Note: The scripts in my GitHub repository are examples only. While they can be used in production environments, they are basic and may not work as expected in all scenarios. For example, the scripts as written today assume only a single VPN profile provisioned. Unexpected results may occur if more than one VPN profile exists. Please use them at your own risk.

Deployment

In this example, we’ll deploy a Proactive Remediation to disable IKE mobility for user tunnel VPN connections. To configure an Intune Proactive Remediation, open the Microsoft Endpoint Manager portal (https://endpoint.microsoft.com/) and navigate to Reports > Endpoint analytics > Proactive remediations. After creating or downloading the detection and remediation scripts, perform the following steps to create and deploy a Proactive Remediation script package.

  1. Click Create script package.
  2. Enter a name for the package in the Name field.
  3. Enter a description for the package in the Description field (optional).
  4. Click Next.
  5. Click the blue folder icon next to the Detection script file field and upload the detection script.
  6. Click the blue folder icon next to the Remediation script file field and upload the associated remediation script.
  7. For user tunnel connections, click Yes next to Run this script using the logged-on credentials. For device tunnel connections, click No.
  8. Click Next.

Assign scope tags and group assignments as necessary, then click Create. Click Refresh to update the UI to display the newly created script package.

Caveats

Be advised that Proactive Remediation script packages run immediately after the first device sync and then every 24 hours after that. Timing issues could lead to delays in functionality. For example, if an Always On VPN profile is provisioned after a Proactive Remediation script runs, the changes made by the remediation script won’t be available until much later. Also, changes made while the VPN is active will not take effect until after restarting the connection.

Special Thanks

Special thanks to Tom Klaver at Inspark for turning me on to this feature. It has been an absolute lifesaver for sure!

Additional Information

Microsoft Intune Proactive Remediation Tutorial

Windows VPN Phonebook Entry Settings

Intune Proactive Remediation Script Samples on GitHub

Microsoft Windows Always On VPN Class-Based Default Route and Intune

Microsoft Windows Always On VPN Short Name Access Failure

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