Deploying DirectAccess in Microsoft Azure

Introduction

DirectAccess Now a Supported Workload in Microsoft AzureMany organizations are preparing to implement DirectAccess on Microsoft’s public cloud infrastructure. Deploying DirectAccess in Azure is fundamentally no different than implementing it on premises, with a few important exceptions (see below). This article provides essential guidance for administrators to configure this unique workload in Azure.

Important Note: There has been much confusion regarding the supportability of DirectAccess in Azure. Historically it has not been supported. Recently, it appeared briefly that Microsoft reversed their earlier decision and was in fact going to support it. However, the Microsoft Server Software Suport for Microsoft Azure Virtual Machines document has once again been revised to indicate that DirectAccess is indeed no longer formally supported on Azure. More details can be found here.

Azure Configuration

The following is guidance for configuring network interfaces, IP address assignments, public DNS, and network security groups for deploying DirectAccess in Azure.

Virtual Machine

Deploy a virtual machine in Azure with sufficient resources to meet expected demand. A minimum of two CPU cores should be provisioned. A VM with 4 cores is recommended. Premium storage on SSD is optional, as DirectAccess is not a disk intensive workload.

Network Interfaces

It is recommended that an Azure VM with a single network interface be provisioned for the DirectAccess role. This differs from on-premises deployments where two network interfaces are preferred because deploying VMs in Azure with two NICs is prohibitively difficult. At the time of this writing, Azure VMs with multiple network interfaces can only be provisioned using PowerShell, Azure CLI, or resource manager templates. In addition, Azure VMs with multiple NICs cannot belong to the same resource group as other VMs. Finally, and perhaps most importantly, not all Azure VMs support multiple NICs.

Internal IP Address

Static IP address assignment is recommended for the DirectAccess VM in Azure. By default, Azure VMs are initially provisioned using dynamic IP addresses, so this change must be made after the VM has been provisioned. To assign a static internal IP address to an Azure VM, open the Azure management portal and perform the following steps:

  1. Click Virtual machines.
  2. Select the DirectAccess server VM.
  3. Click Network Interfaces.
  4. Click on the network interface assigned to the VM.
  5. Under Settings click IP configurations.
  6. Click Ipconfig1.
  7. In the Private IP address settings section choose Static for the assignment method.
  8. Enter an IP address for the VM.
  9. Click Save.

Deploying DirectAccess in Microsoft Azure

Public IP Address

The DirectAccess VM in Azure must have a public IP address assigned to it to allow remote client connectivity. To assign a public IP address to an Azure VM, open the Azure management portal and perform the following steps:

  1. Click Virtual machines.
  2. Select the DirectAccess server VM.
  3. Click Network Interfaces.
  4. Click on the network interface assigned to the VM.
  5. Under Settings click IP configurations.
  6. Click Ipconfig1.
  7. In the Public IP address settings section click Enabled.
  8. Click Configure required settings.
  9. Click Create New and provide a descriptive name for the public IP address.
  10. Choose an address assignment method.
  11. Click Ok and Save.

Deploying DirectAccess in Microsoft Azure

Deploying DirectAccess in Microsoft Azure

Public DNS

If the static IP address assignment method was chosen for the public IP address, create an A resource record in public DNS that resolves to this address. If the dynamic IP address assignment method was chosen, create a CNAME record in public DNS that maps to the public hostname for the DirectAccess server. To assign a public hostname to the VM in Azure, open the Azure management portal and perform the following steps:

  1. Click Virtual machines.
  2. Select the DirectAccess server VM.
  3. Click Overview.
  4. Click Public IP address/DNS name label.Deploying DirectAccess in Microsoft Azure
  5. Under Settings click Configuration.
  6. Choose an assignment method (static or dynamic).
  7. Enter a DNS name label.
  8. Click Save.

Deploying DirectAccess in Microsoft Azure

Note: The subject of the SSL certificate used for the DirectAccess IP-HTTPS listener must match the name of the public DNS record (A or CNAME) entered previously. The SSL certificate does not need to match the Azure DNS name label entered here.

Network Security Group

A network security group must be configured to allow IP-HTTPS traffic inbound to the DirectAccess server on the public IP address. To make the required changes to the network security group, open the Azure management portal and perform the following steps:

  1. Click Virtual machines.
  2. Select the DirectAccess server VM.
  3. Click Network interfaces.
  4. Click on the network interface assigned to the VM.
  5. Under Settings click Network security group.
  6. Click the network security group assigned to the network interface.
  7. Click Inbound security rules.
  8. Click Add and provide a descriptive name for the new rule.
  9. Click Any for Source.
  10. From the Service drop-down list choose HTTPS.
  11. Click Allow for Action.
  12. Click Ok.

Deploying DirectAccess in Microsoft Azure

Note: It is recommended that the default-allow-rdp rule be removed if it is not needed. At a minimum, scope the rule to allow RDP only from trusted hosts and/or networks.

DirectAccess Configuration

When performing the initial configuration of DirectAccess using the Remote Access Management console, the administrator will encounter the following warning message.

“One or more network adapters should be configured with a static IP address. Obtain a static address and assign it to the adapter.”

Deploying DirectAccess in Microsoft Azure

This message can safely be ignored because Azure infrastructure handles all IP address assignment for hosted VMs.

The public name of the DirectAccess server entered in the Remote Access Management console must resolve to the public IP address assigned to the Azure VM, as described previously.

Deploying DirectAccess in Microsoft Azure

Additional Considerations

When deploying DirectAccess in Azure, the following limitations should be considered.

Load Balancing

It is not possible to enable load balancing using Windows Network Load Balancing (NLB) or an external load balancer. Enabling load balancing for DirectAccess requires changing static IP address assignments in the Windows operating system directly, which is not supported in Azure. This is because IP addresses are assigned dynamically in Azure, even when the option to use static IP address assignment is chosen in the Azure management portal. Static IP address assignment for Azure virtual machines are functionally similar to using DHCP reservations on premises.

Deploying DirectAccess in Microsoft Azure

Note: Technically speaking, the DirectAccess server in Azure could be placed behind a third-party external load balancer for the purposes of performing SSL offload or IP-HTTPS preauthentication, as outlined here and here. However, load balancing cannot be enabled in the Remote Access Management console and only a single DirectAccess server per entry point can be deployed.

Manage Out

DirectAccess manage out using native IPv6 or ISATAP is not supported in Azure. At the time of this writing, Azure does not support IPv6 addressing for Azure VMs. In addition, ISATAP does not work due to limitations imposed by the underlying Azure network infrastructure.

Summary

For organizations moving infrastructure to Microsoft’s public cloud, formal support for the DirectAccess workload in Azure is welcome news. Implementing DirectAccess in Azure is similar to on-premises with a few crucial limitations. By following the guidelines outlined in this article, administrators can configure DirectAccess in Azure to meet their secure remote access needs with a minimum of trouble.

Additional Resources

Implementing DirectAccess in Windows Server 2016
Fundamentals of Microsoft Azure 2nd Edition
Microsoft Azure Security Infrastructure
DirectAccess Multisite with Azure Traffic Manager
DirectAccess Consulting Services

Windows 10 Multisite DirectAccess with GSLB Webinar

Kemp Technologies LoadMaster Load BalancerWindows 10 clients include full support for all enterprise DirectAccess scalability and redundancy features, including automatic site selection and transparent failover for multisite deployments. However, the native site selection process is limited in functionality and often yields unexpected results.

To provide better client support for multisite DirectAccess, a Global Server Load Balancer (GSLB) solution such as the Kemp Technologies LoadMaster GEO can be deployed. Using the LoadMaster’s GSLB functionality can significantly enhance multisite site selection for Windows 10 clients. In addition, it can be used to enable new scenarios not supported natively such as weighted distribution and active/passive failover.

Kemp Technologies LoadMaster Load Balancer

To learn more about how address the shortcomings of DirectAccess multisite using the Kemp LoadMaster GEO, join me for a live webinar on Thursday, July 14, 2106 at 10:00AM EDT where I’ll discuss the following topics.

  • How Global Server Load Balancing (GSLB) works
  • How Windows 10 clients choose an entry point
  • Understand the limitations of the native site selection process for Windows 10 clients
  • How to use the Kemp LoadMaster GEO to provide true geographic redundancy
  • How to enable active/passive failover for disaster recovery

You can register for this free live webinar here.

DirectAccess Multisite Geographic Redundancy with Microsoft Azure Traffic Manager

Introduction

DirectAccess Multisite Geographic Redundancy with Microsoft Azure Traffic ManagerTo provide geographic redundancy, DirectAccess can be deployed in a multisite configuration. In this scenario, Windows 8.x and Windows 10 clients are aware of all entry points in the enterprise and will automatically select the nearest available entry point to connect to. The nearest entry point is defined as the one that responds the quickest. When a Windows 8.x or Windows 10 client attempts to establish DirectAccess connectivity, an HTTP GET is sent to all entry points and the client will select the one with the shortest Round Trip Time (RTT) for the request.

Note: Windows 7 clients can be provisioned when DirectAccess is configured for multisite access, but they must be assigned to an individual entry point.

Challenges

There are a number of challenges that come with the default multisite configuration. Choosing an entry point based solely on network latency is rather simplistic and can often produce unexpected results. It also lacks support for granular traffic distribution or active/passive configuration.

GSLB

DirectAccess Multisite Geographic Redundancy with Microsoft Azure Traffic ManagerFor the best experience, DirectAccess can be configured to use a Global Server Load Balancing (GSLB) solution to enhance transparent site selection and failover for Windows 8.x and Windows 10 clients. Commonly this is implemented using an on-premises appliance (Citrix NetScaler, F5 Global Traffic Manager, Kemp LoadMaster, A10 Thunder, etc.). These solutions offer exceptional control over DirectAccess traffic distribution, but they add expense and complexity.

Azure Traffic Manager

Azure Traffic Manager is a cloud-based GSLB solution that is a simple and cost-effective alternative to dedicated on-premises appliances. While it does not offer all of the features that GSLB appliances provide, it does provide better traffic distribution options than the default configuration. Importantly, it enables active/passive failover, which is a common requirement not supported natively with DirectAccess.

DirectAccess Multisite Geographic Redundancy with Microsoft Azure Traffic Manager

Traffic Manager Configuration

In the Azure portal (the new one, not the old one!) click New, Networking, and then Traffic Manager profile.

DirectAccess Multisite Geographic Redundancy with Microsoft Azure Traffic Manager

Provide a name and select a Routing method.

DirectAccess Multisite Geographic Redundancy with Microsoft Azure Traffic Manager

Routing method options are Performance, Weighted and Priority.

  • Performance. Select this option to enable clients to connect to the entry point with the lowest network latency.
  • Weighted. Select this option to enable clients to prefer some entry points more than others. Assign a weight value of 1 to 1000 for each entry point. Higher values have more preference. Values for entry points can be the same, if desired.
  • Priority. Select this option to enable clients to connect to a primary entry point, then fail over to a secondary or tertiary entry point in the event of an outage. Assign a priority value of 1 to 1000 for each entry point. Lower values take precedence. Each entry point must be assigned a unique priority value.

Click Create when finished. Next click Settings for the new traffic manager profile and click Configuration. Change Protocol to HTTPS, Port to 443, and Path to /IPHTTPS. Click Save when finished.

DirectAccess Multisite Geographic Redundancy with Microsoft Azure Traffic Manager

Next click Endpoints and click Add. Select External endpoint from the drop down list, provide a descriptive name, and then enter the Fully-Qualified Domain Name (FQDN) of the first DirectAccess entry point. When using the Performance routing method, choose a location that best represents the geography where the DirectAccess entry point is located. When using the Weighted or Priority routing methods, specify an appropriate value accordingly. Click Ok when finished. Repeat these steps for each entry point in the organization.

DirectAccess Multisite Geographic Redundancy with Microsoft Azure Traffic Manager

DirectAccess Configuration

In the Remote Access Management console, highlight DirectAccess and VPN below Configuration in the navigation tree and then click Configure Multisite Settings below Multisite Deployment in the Tasks pane. Click Global Load Balancing and choose Yes, use global load balancing. Enter the FQDN of the Azure Traffic Manager profile and click Next, and then click Commit.

DirectAccess Multisite Geographic Redundancy with Microsoft Azure Traffic Manager

Note: An SSL certificate with a subject name matching that of the GSLB FQDN is not required.

In some cases, the management console may report that global load balancing addresses cannot be identified automatically for some or all entry points.

DirectAccess Multisite Geographic Redundancy with Microsoft Azure Traffic Manager

If this occurs, it will be necessary to run the Set-DAEntryPoint PowerShell cmdlet to assign GLSB IP addresses to each entry point. The GSLB IP address is the public IPv4 address that the entry point public hostname resolves to.

Set-DAEntryPoint -Name [entrypoint_name] -GslbIP [external_ip_address]

For example:

Set-DAEntryPoint -Name "US West" -GslbIP 203.0.113.195
Set-DAEntryPoint -Name "US East" -GslbIP 198.51.100.21

Summary

DirectAccess includes native functionality to enable geographic load balancing for Windows 8.x and Windows 10 clients. The site selection process used by DirectAccess clients in this scenario is basic, and has the potential to yield unexpected results. Azure Traffic Manager is a simple, cost-effective alternative to dedicated on-premises GSLB appliances. It can be integrated with DirectAccess to address some of the shortcomings with the native entry point selection process.

Additional Resources

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