10 PowerShell Commands Always On VPN Administrators Should Know

Managing a secure and reliable VPN infrastructure is critical for supporting today’s highly mobile workforce. For Always On VPN administrators, PowerShell is an indispensable tool for achieving this goal. Not only can PowerShell be used to automate the installation and configuration of Windows Server Routing and Remote Access Service (RRAS) server, but it can also be used to audit configuration and monitor system health and user activity as well. In addition, it is highly recommended that the RRAS role be installed on Server Core for optimum security and performance. Administrators must be familiar with these PowerShell commands and more to support RRAS on Windows Server Core in their environment.

RemoteAccess Module

The RemoteAccess PowerShell module should be installed when the RRAS server is configured. There are 122 commands in this module, but only a subset of those pertain to the VPN server role. Here are ten popular commands for monitoring and managing an Always On VPN RRAS server.

Configuration Review

The following PowerShell commands are useful for reviewing the current RRAS server configuration.

Get-RemoteAccess – Displays the current configuration of the VPN server. Details include installation status, TLS certificate configuration, VPN client IP address assignment method, IPv4 and IPv6 addressing information (if using the static address assignment method), authentication type, and configured RADIUS servers.

Get-VpnAuthProtocol – Displays authentication configuration details such as accepted authentication types for both user and device connections, root certification authority (CA) certificate restrictions (if enabled), and certificate advertisement and EKU restrictions if enabled.

Get-VpnServerConfiguration – Displays additional VPN server configuration information, such as the IPsec configuration for IKEv2, the number of VPN ports configured, and more.

System Health

Get-RemoteAccessHealth – Displays the current health status of various VPN server services. The command’s default output is a little noisy. I recommend filtering it as follows:

Get-RemoteAccessHealth | Where-Object HealthState -NotMatch Disabled | Format-Table -AutoSize

User Activity

The following PowerShell commands can be used to view current and historical user activity details.

Get-RemoteAccessConnectionStatistics – Displays all active VPN connections on the server.

Get-RemoteAccessConnectionStatisticsSummary – Displays cumulative information about VPN connections on the server since the last service restart or reboot, such as the total number of connections, the number of unique users, the maximum number of concurrent connections, and the amount of data transferred.

Get-RemoteAccessUserActivity – Displays all active VPN connections for a specific user or device.

Management

The following PowerShell commands are helpful for reviewing authentication and logging settings.

Get-RemoteAccessRadius – Allows the administrator to view the currently configured RADIUS servers on the VPN server.

Get-RemoteAccessAccounting – Allows the administrator to view the current accounting repository (RADIUS or inbox) on the VPN server.

Clear-RemoteAccessInboxAccountingStore – Allows the administrator to remove log data from the Inbox Accounting database. Removing log data from the database can be helpful when transitioning a test server to production or to free up disk space by reducing the size of the logging database.

Additional Modules

In addition to the PowerShell commands above, Always On VPN administrators can leverage my custom PowerShell modules for advanced server and client configuration. These modules are published in the PowerShell Gallery.

AovpnTools – PowerShell module to configure and optimize Windows RRAS servers to support Always On VPN.

Install-Module -Name AovpnTools

InboxAccountingDatabaseManagement – PowerShell module to configure and manage the Inbox Accounting database for logging system information and user activity on the VPN server.

Install-Module -Name InboxAccountingDatabaseManagement

Additional Information

Always On VPN and RRAS on Windows Server Core

Inbox Accounting Database Management

AovpnTools PowerShell Module on GitHub

Inbox Accounting Database Module on GitHub

Always On VPN SSTP Load Balancing with F5 BIG-IP

Always On VPN SSTP Load Balancing with F5 BIG-IP The Windows Server Routing and Remote Access Service (RRAS) includes support for the Secure Sockets Tunneling Protocol (SSTP), which is a Microsoft proprietary VPN protocol that uses SSL/TLS for security and privacy of VPN connections. The advantage of using SSTP for Always On VPN is that it is firewall friendly and ensures consistent remote connectivity even behind highly restrictive firewalls.

Load Balancing SSTP

In a recent post, I described some of the use cases and benefits of SSTP load balancing as well as the offloading of TLS for SSTP VPN connections. Using a load balancer for SSTP VPN connections increases scalability, and offloading TLS for SSTP reduces resource utilization and improves performance for VPN connections. There are positive security benefits too.

Configuration

Enabling load balancing for SSTP on the F5 BIG-IP load balancer is fundamentally similar to load balancing HTTPS web servers. However, there are a few subtle but important differences.

Default Monitor

The default HTTP and HTTPS monitors on the F5 will not accurately reflect the health of the SSTP service running on the RRAS server. In addition, using a simple TCP port monitor could yield unexpected results. To ensure accurate service status monitoring, a new custom monitor must be created to validate the health of the SSTP service.

Custom SSTP Monitor

Open the F5 BIG-IP management console and follow the steps below to create and assign a new custom monitor for SSTP.

Create Monitor

1. In the navigation tree highlight Local Traffic.
2. Click Monitors.
3. Click Create.

Always On VPN SSTP Load Balancing with F5 BIG-IP

4. Enter a descriptive name in the Name field and from the Type drop-down list choose HTTP if TLS offload is enabled, or HTTPS if it is not.
5. In the Send String field enter HEAD /sra_{BA195980-CD49-458b-9E23-C84EE0ADCD75}/ HTTP/1.1\r\nHost:r\nConnection: Close\r\n\r\n.
6. In the Receive String field enter HTTP/1.1 401.
7. Click Finished.

Always On VPN SSTP Load Balancing with F5 BIG-IP

Assign Monitor

1. Below Local Traffic click Pools.
2. Click on the SSTP VPN server pool.
3. In the Health Monitors section select the SSTP VPN health monitor from the Available list and make it Active.
4. Click Update.

Always On VPN SSTP Load Balancing with F5 BIG-IP

CLI Configuration

If you prefer to configure the SSTP VPN monitor using the F5’s Command Line Interface (CLI), you can download the monitor configuration from my GitHub here.

TLS Offload

It is generally recommended that TLS offload not be enabled for SSTP VPN. However, if TLS offload is desired, it is configured in much the same way as a common HTTPS web server. Specific guidance for enabling TLS offload on the F5 BIG-IP can be found here. Details for configuring RRAS and SSTP to support TLS offload can be found here.

Certificates

When enabling TLS offload for SSTP VPN connections it is recommended that the public SSL certificate be installed on the RRAS server, even though TLS processing will be handled on the F5 and HTTP will be used between the F5 and the RRAS server. If installing the public SSL certificate on the RRAS server is not an option, additional configuration will be required. Specifically, TLS offload for SSTP must be configured using the Enable-SSTPOffload PowerShell script, which can be found here.

Once the script has been downloaded, open an elevated PowerShell command window and enter the following command.

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

Example:

Enable-SSTPOffload -CertificateHash “C3AB8FF13720E8AD9047DD39466B3C8974E592C2FA383D4A3960714CAEF0C4F2” -Restart

Re-Encryption

When offloading TLS for SSTP VPN connections, all traffic between the F5 and the RRAS server will be sent in the clear using HTTP. In some instances, TLS offload is required only for traffic inspection, not performance gain. In this scenario the F5 will be configured to terminate and then re-encrypt connections to the RRAS server. When terminating TLS on the F5 and re-encrypting connections to the RRAS server is required, the same certificate must be used on both the F5 and the RRAS server. Using different certificates on the RRAS server and the load balancer is not supported.

Additional Information

Windows 10 Always On VPN SSTP Load Balancing and SSL Offload

Windows 10 Always On VPN SSL Certificate Requirements for SSTP

Windows 10 Always On VPN ECDSA SSL Certificate Request for SSTP

Windows 10 Always On VPN SSTP Connects then Disconnects

Windows 10 Always On VPN Load Balancing Deployment Guide for Kemp Load Balancers