DirectAccess on Windows Server 2016 Core

DirectAccess on Windows Server 2016 CoreDeploying DirectAccess on Windows Server 2016 core is recommended to ensure the highest level of security and availability for the remote access solution. Server core is a stripped-down, command-line only version of Windows that removes many features unnecessary to support common server workloads. It’s reduced attack surface improves security, and this leaner version of the Windows OS requires less maintenance (patching), resulting in fewer reboots which increases overall availability. It has a smaller disk and memory footprint too which results in quicker system restarts, when required.

Removing the GUI

Historically I’ve recommended that DirectAccess administrators deploy Windows server with the full GUI first, then remove it later after validation testing is complete. Prior to placing it in production, the GUI can be removed by running the following PowerShell command.

Uninstall-WindowsFeature Server-Gui-Mgmt-Infra -Restart

This works flawlessly in Windows Server 2012 and Windows Server 2012 R2. However, when running this command on a Windows Server 2016 server you will receive the following error message.

Uninstall-WindowsFeature : ArgumentNotValid: The role, role service, or feature name is not valid:
‘Server-Gui-Mgmt-Infra’. The name was not found.

DirectAccess on Windows Server 2016 Core

Changes in Windows Server 2016

This happens because Microsoft quietly removed the option to switch back and forth between the full GUI version and the core version of Windows beginning with Windows Server 2016.

DirectAccess on Windows Server 2016 Core

Source: https://docs.microsoft.com/en-us/windows-server/get-started/getting-started-with-server-core

It is still recommended that DirectAccess be deployed on server core to provide the most secure and reliable experience. However, since it is no longer possible to switch from GUI to core, it must be deployed in serve core configuration upon initial installation.

Additional Information

DirectAccess and Windows Server 2012 R2 Core

Configure Windows Server Core to use PowerShell by Default

Planning and Implementing DirectAccess with Windows Server 2016 Video Training Course

Managing and Supporting DirectAccess with Windows Server 2016 Video Training Course

Implementing DirectAccess with Windows Server 2016 Book

DirectAccess and Windows Server 2012 R2 Core

Important Note: The ability to switch back and forth between the full GUI and core versions of Windows was removed from Windows Server 2016. If you are deploying DirectAccess on Windows Server 2016, you must install server core initially. More details here.

DirectAccess and Windows Server 2012 R2 Core

Windows Server Core is an operating system configuration option that does not include a Graphical User Interface (GUI). Server Core was first introduced with Windows Server 2008 and originally included only a limited number of supported roles. With each subsequent release, Microsoft continues to add support for additional roles on Server Core. Beginning with Windows Server 2012, the Routing and Remote Access (RRAS) role, which includes DirectAccess, is a supported workload on Server Core.

Advantages of Server Core

There are a number of important advantages that come with running DirectAccess on Server Core. Server Core has a greatly reduced attack surface compared to the full GUI version, which is positive from a security perspective. Server Core also features a dramatically reduced footprint, consuming less RAM and disk space. System startup times are faster, and this refactored installation option also reduces servicing requirements (patching), eliminating many reboots and increasing availability and overall system uptime.

DirectAccess and Windows Server 2012 R2 Core

Figure 1 – Windows Server 2012 R2 Core Desktop (Yes, that’s it!)

Server Core Configuration

DirectAccess is a workload that lends itself well to running on Server Core, and I highly recommend leveraging this configuration whenever possible. Based on my experience, I suggest performing initial configuration and testing of the DirectAccess solution with the GUI installed, and then removing the GUI just before placing the DirectAccess server in to production. Removing the GUI can be accomplished by executing the following PowerShell command:

Remove-WindowsFeature Server-Gui-Mgmt-Infra –Restart

Once the server has been converted to Server Core, all administration must be performed at the command line on the server, or remotely from a management server or workstation using the command line or GUI administration tools. You can install the Remote Access Management console on any Windows Server 2012 R2 server using the following PowerShell command:

Install-WindowsFeature RSAT-RemoteAccess

Optionally you can download and install the Windows Server Remote Administrations Tools (RSAT) on a Windows client workstation, if desired.

Minimal Server Interface Configuration

If you prefer to be able to manage the DirectAccess server locally using the GUI, consider enabling the Minimal Server Interface. Minimal Server Interface is a configuration option that lies between Server Core and the full GUI interface. It features some of the benefits of Server Core, while at the same time providing local access to GUI management tools such as the Remote Access Management console. You can configure Minimal Server Interface using the following PowerShell command:

Remove-WindowsFeature Server-Gui-Shell -Restart

You can access the Remote Access Management console by entering RaMgmtUI.exe from the command line.

Revert to Full GUI

If at any point in the future you require the GUI for some reason, re-installing it can be accomplished using the following PowerShell command:

Install-WindowsFeature Server-Gui-Shell –Restart

Summary

With the Unified Remote Access role supported on Windows Server Core, consider implementing DirectAccess using this option to improve the security and increase the availability of your remote access solution. You’ll find that almost all ongoing server maintenance and support can be accomplished remotely using GUI tools, or locally using PowerShell. And if you ever need the GUI again, you can always add it back if necessary!

Additional Resources

DirectAccess on Windows Server 2016 Core

%d bloggers like this: