All posts tagged troubleshooting

Always On VPN and Interface Metrics

Always On VPN DNS Registration Update Available

In Windows, each network interface identified by the operating system is assigned a metric value. Interface metrics are settings that determine the priority or preference of network interfaces when there are multiple active network connections. The Windows networking stack uses these metrics to determine which network interface should be used for routing traffic when multiple network interfaces are available. Network interface metrics are critical for Always On VPN administrators to understand because they can impact how name resolution requests are processed when an Always On VPN connection is established.

Metric Values

By default, Windows automatically assigns metric values to network interfaces (including VPN interfaces) based on various factors, including the connection speed, link state, and interface type. It tries to select the most suitable interface for general internet connectivity.

Metrics and DNS

Windows will also use the network interface with the lowest metric value as the preferred interface for sending DNS queries by default. This means that DNS queries will be routed through the network interface with the lowest metric value, assuming it is available and connected. When an Always On VPN connection is established, DNS queries may fail or return unexpected results if the network interface metrics are not configured optimally.

Split DNS and Wired Ethernet

Split DNS (sometimes called ‘split brain DNS’) is when the DNS namespace is the same internally and externally. The most common scenario where interface metric settings interfere with DNS operation is when using split DNS and the endpoint is connected to the Internet with a wired Ethernet connection. In this scenario, the Ethernet interface will be assigned the same or lower interface metric value as the Always On VPN interface, which can yield unexpected results.

Viewing Metrics

Always On VPN administrators can view currently assigned interface metric values by running the following PowerShell command.

Get-NetIpInterface

Assigning Metrics

Most Always On VPN administrators will never have to change interface metric settings. However, if your implementation uses split DNS and some of your endpoints connect using wired Ethernet connections, you may need to update the interface metric settings to ensure proper DNS operation. Choose a setting for the interface metric value that is lower than the wired Ethernet interface. I’ve used a value of ‘3’ without issue for many years. Use one of the following methods to update the interface metric for Always On VPN connections.

PowerShell

Updating interface metric settings in Windows can be accomplished by running the Set-NetIpInterface PowerShell command.

Set-NetIpInterface -InterfaceAlias <connection name> -InterfaceMetric 3

Note: Using PowerShell to assign the interface metric is not persistent! While this method is suitable for local validation testing, you should use one of the following methods to implement this change permanently.

Rasphone.pbk

To assign the interface metric permanently, Always On VPN administrators can edit the following settings in the rasphone.pbk configuration file.

IpInterfaceMetric=3

Ipv6InterfaceMetric=3

Administrators can automate updating this setting using the Update-Rasphone.ps1 PowerShell script. In addition, the following scripts can be used with Microsoft Intune remediation.

Detect-DeviceIpv4InterfaceMetric.ps1

Remediate-DeviceIpv4InterfaceMetric.ps1

Detect-DeviceIpv6InterfaceMetric.ps1

Remediate-DeviceIpv6InterfaceMetric.ps1

Detect-Ipv4InterfaceMetric.ps1

Remediate-Ipv4InterfaceMetric.ps1

Detect-Ipv6InterfaceMetric.ps1

Remediate-Ipv6InterfaceMetric.ps1

DPC

Organizations using PowerON Platforms’ Dynamic Profile Configurator (DPC) to manage Always On VPN client configuration settings with Active Directory and group policy or Microsoft Intune can enable the VPN Tunnel Metric setting.

Additional Information

Get-NetIpInterface PowerShell Command

Set-NetIpInterface PowerShell Command

Managing Always On VPN Client Settings with DPC

Always On VPN DPC with Microsoft Intune

Always On VPN DPC Advanced Features

Always On VPN DPC Video Demonstration

PowerON Platforms Always On VPN Dynamic Profile Configurator (DPC)

7 Comments
by Richard M. Hicks on September 25, 2023  •  Permalink
Posted in Active Directory, administration, Always On VPN, Always On VPN DPC, AOVPN, AovpnDPC, Deployment, Device Management, device tunnel, DNS, DPC, Dynamic Profile Configurator, Endpoint Manager, Enterprise, enterprise mobility, Group Policy, HAADJ, Hybrid Azure AD Join, Infrastructure, MDM, MEM, MEMCM, Microsoft, Microsoft Endpoint Manager, Microsoft Intune, Mobile Device Management, Mobility, Name Resolution, Operational Support, PowerShell, ProfileXML, Remote Access, Split DNS, split tunnel, split tunneling, systems management, user tunnel, VPN, Windows 10, Windows 11, XML
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Posted by Richard M. Hicks on September 25, 2023

https://directaccess.richardhicks.com/2023/09/25/always-on-vpn-and-interface-metrics/

Always On VPN and the PSPKI PowerShell Module

Certificates are a crucial part of a secure Always On VPN implementation. Certificates are phishing-resistant forms of authentication that, when configured correctly, provide robust and multifactor authentication for remote access users and devices.

AD CS

Most commonly, certificates are issued by an on-premises Microsoft Active Directory Certificate Services (AD CS) server. Administrators configure and deploy a Certification Authority infrastructure to issue and manage user and device authentication certificates in their organization. CA certificates are also required on the VPN server to support Always On VPN device tunnel connections and IKEv2 user tunnel connections. The NPS server also requires an enterprise CA certificate. Of course, the CA can issue certificates for other purposes, including Wi-Fi authentication, document signing, and code signing, just to name a few.

PSPKI

PSPKI is a PowerShell module available in the PowerShell Gallery for configuring, managing, and troubleshooting Microsoft AD CS. Created by Vadims Podans of PKI Solutions, PSPKI includes over 100 functions for various AD CS and certificate-related tasks. Always On VPN administrators will find this PowerShell module helpful when configuring and troubleshooting certificate-related issues for their Always On VPN deployments.

Note: The AD CS remote server administration tools (RSAT) must be installed to access all of the PSPKI module’s functionality.

Installation

Run the following PowerShell command to install the PSPKI PowerShell module.

Install-Module -Name PSPKI

Always On VPN and PSPKI

Always On VPN Administrators will immediately find a few PSPKI functions helpful when implementing and supporting Always On VPN.

Test-WebServerSSL – This function will connect to a remote web server and display details about the TLS certificate included in the response. This can be especially helpful when troubleshooting SSTP VPN connections.

Convert-PfxToPem – This is a handy utility for converting a PFX file to the PEM format. This is commonly required when importing CA certificates on non-Microsoft platforms, security devices, and load balancers.

Convert-PemToPfx – Occasionally, administrators must convert a certificate and private key in PEM format to PFX to install on a Windows server. This tool allows administrators to perform this task easily.

Get-CertificationAuthority – This function quickly enumerates all enterprise CA servers and displays information about their hostname, accessibility, service status, and type.

Ping-ICertInterface – This function helps troubleshoot CA connectivity issues. Administrators can quickly determine if a CA is reachable and capable of issuing a certificate using this command.

Get-CaTemplate – This command displays a list of certificate templates published on the specified target CA server. The certificate template’s display name and the minimum support CA version are provided. In addition, the output indicates if certificate autoenrollment is enabled on the template.

Much More

The PSPKI PowerShell module for AD CS has many tools for configuring and managing AD CS. PSPKI recently received a major update to version 4.0. Download and install PSPKI today. It will make your life easier, I can assure you!

Additional Information

PSPKI PowerShell Module – PowerShell Gallery

PSPKI PowerShell Module – GitHub

AOVPNTools PowerShell Module – PowerShell Gallery

AOVPNTools PowerShell Module – GitHub

InboxAccountingDatabaseManagement PowerShell Module

InboxAccontingDatabaseManagement – PowerShell Gallery

InboxAccountingDatabaseManagement – GitHub

4 Comments
by Richard M. Hicks on June 20, 2023  •  Permalink
Posted in Active Directory, administration, Always On VPN, AOVPN, authentication, certificates, Deployment, Encryption, Enterprise, enterprise mobility, GitHub, IKEv2, Infrastructure, Microsoft, Mobility, Multifactor Authentiction, NPS, Operational Support, PEAP, PKI, PowerShell, Protected EAP, public key infrastructure, Remote Access, routing and remote access service, RRAS, Secure Socket Tunneling Protocol, Security, SSL, SSL and TLS, SSTP, systems management, TLS, Transport Layer Security, troubleshooting, Update, user tunnel, VPN, Windows 10, Windows 11, Windows Server 2012 R2, Windows Server 2016, Windows Server 2019, Windows Server 2022
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Posted by Richard M. Hicks on June 20, 2023

https://directaccess.richardhicks.com/2023/06/20/always-on-vpn-and-the-pspki-powershell-module/

Always On VPN Error 13868

Troubleshooting Always On VPN Error 691 and 812 – Part 2

The Internet Key Exchange version 2 (IKEv2) VPN protocol is the protocol of choice for Microsoft Always On VPN deployments where the highest levels of security and assurance are required. However, as I’ve written about in the past, often the default IKEv2 security settings are less than desirable. Before using IKEv2 VPN in a production environment the administrator will need to update these security settings accordingly.

Connection Failure

When configuring Windows Server Routing and Remote Access Service (RRAS) or a third-party VPN appliance to support IKEv2 using custom security policies, the administrator may encounter a scenario in which a connection cannot be established due to a policy mismatch error. When the connection attempt fails, an error will be recorded in the Windows Application event log from the RasClient source with Event ID 20227. 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 13868.”

Always On VPN IKEv2 Policy Mismatch Error

Error Code 13868

Error code 13868 translates to ERROR_IPSEC_IKE_POLICY_MATCH. Essentially this error indicates that the IKEv2 security policy on the client did not match the configuration on the server.

Server Configuration

To view the current IKEv2 IPsec policy configuration, open an elevated PowerShell command window and run the following command.

Get-VpnServerIPsecConfiguration

Always On VPN IKEv2 Policy Mismatch Error

Client Configuration

To ensure interoperability, the VPN client must be configured to use the same IKEv2 security policy as defined on the sever. To view a VPN client’s currently configured IKEv2 security policy, open an elevated PowerShell command window and run the following command.

Get-VpnConnection -Name [connection name] | Select-Object -ExpandProperty IPsecCustomPolicy

Always On VPN IKEv2 Policy Mismatch Error

Note: If this PowerShell command returns no output, the VPN connection is not using a custom IKEv2 IPsec security policy.

Updating Settings

Guidance for configuring IKEv2 security policies on Windows Server RRAS and Windows 10 can be found here.

NPS Policy

Another common cause of IKEv2 policy mismatch errors is a misconfigured Network Policy Server (NPS) network policy. Specifically, administrators may disable Basic and Strong encryption for MPPE in an attempt to improve security.

Always On VPN IKEv2 Policy Mismatch Error

The NPS policy for Always On VPN must include Strong encryption at a minimum. Basic and No encryption can be safely disabled.

Always On VPN IKEv2 Policy Mismatch Error

Summary

IKEv2 policy mismatch errors can be resolved easily by ensuring both the VPN server and client are configured to use the same IPsec security policies. Use the PowerShell commands in the above referenced above to validate settings and make changes when necessary.

Additional Information

Microsoft Always On VPN Error 13801

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

1 Comment
by Richard M. Hicks on February 12, 2023  •  Permalink
Posted in Always On VPN, AOVPN, authentication, Azure VPN, Azure VPN Gateway, certificates, Cryptography, device tunnel, Encryption, Enterprise, enterprise mobility, IKEv2, Infrastructure, Microsoft, Mobility, network policy server, NPS, Operational Support, PKI, PowerShell, Remote Access, routing and remote access service, Security, troubleshooting, VPN, Windows 10, Windows 11, Windows Server 2012 R2, Windows Server 2016, Windows Server 2019, Windows Server 2022
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Posted by Richard M. Hicks on February 12, 2023

https://directaccess.richardhicks.com/2023/02/12/always-on-vpn-error-13868/

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