DirectAccess Manage Out with ISATAP and NLB Clustering

DirectAccess Manage Out with ISATAP and NLB ClusteringDirectAccess connections are bidirectional, allowing administrators to remotely connect to clients and manage them when they are out of the office. DirectAccess clients use IPv6 exclusively, so any communication initiated from the internal network to remote DirectAccess clients must also use IPv6. If IPv6 is not deployed natively on the internal network, the Intrasite Automatic Tunnel Addressing Protocol (ISATAP) IPv6 transition technology can be used to enable manage out.

ISATAP Supportability

According to Microsoft’s support guidelines for DirectAccess, using ISATAP for manage out is only supported for single server deployments. ISATAP is not supported when deployed in a multisite or load-balanced environment.

Not supported” is not the same as “doesn’t work” though. For example, ISATAP can easily be deployed in single site DirectAccess deployments where load balancing is provided using Network Load Balancing (NLB).

ISATAP Configuration

To do this, you must first create DNS A resource records for the internal IPv4 address for each DirectAccess server as well as the internal virtual IP address (VIP) assigned to the cluster.

DirectAccess Manage Out with ISATAP and NLB Clustering

Note: Do NOT use the name ISATAP. This name is included in the DNS query block list on most DNS servers and will not resolve unless it is removed. Removing it is not recommended either, as it will result in ALL IPv6-enabled hosts on the network configuring an ISATAP tunnel adapter.

Once the DNS records have been added, you can configure a single computer for manage out by opening an elevated PowerShell command window and running the following command:

Set-NetIsatapConfiguration -State Enabled -Router [ISATAP FQDN] -PassThru

DirectAccess Manage Out with ISATAP and NLB Clustering

Once complete, an ISATAP tunnel adapter network interface with a unicast IPv6 address will appear in the output of ipconfig.exe, as shown here.

DirectAccess Manage Out with ISATAP and NLB Clustering

Running the Get-NetRoute -AddressFamily IPv6 PowerShell command will show routes to the client IPv6 prefixes assigned to each DirectAccess server.

DirectAccess Manage Out with ISATAP and NLB Clustering

Finally, verify network connectivity from the manage out host to the remote DirectAccess client.

Note: There is a known issue with some versions of Windows 10 and Windows Server 2016 that may prevent manage out using ISATAP from working correctly. There’s a simple workaround, however. More details can be found here.

Group Policy Deployment

If you have more than a few systems on which to enable ISATAP manage out, using Active Directory Group Policy Objects (GPOs) to distribute these settings is a much better idea. You can find guidance for creating GPOs for ISATAP manage out here.

DirectAccess Client Firewall Configuration

Simply enabling ISATAP on a server or workstation isn’t all that’s required to perform remote management on DirectAccess clients. The Windows firewall running on the DirectAccess client computer must also be configured to securely allow remote administration traffic from the internal network. Guidance for configuring the Windows firewall on DirectAccess clients for ISATAP manage out can be found here.

ISATAP Manage Out for Multisite and ELB

The configuration guidance in this post will not work if DirectAccess multisite is enabled or external load balancers (ELB) are used. However, ISATAP can still be used. For more information about enabling ISATAP manage out with external load balancers and/or multisite deployments, fill out the form below and I’ll provide you with more details.

Summary

Once ISATAP is enabled for manage out, administrators on the internal network can remotely manage DirectAccess clients wherever they happen to be. Native Windows remote administration tools such as Remote Desktop, Windows Remote Assistance, and the Computer Management MMC can be used to manage remote DirectAccess clients. In addition, enterprise administration tools such as PowerShell remoting and System Center Configuration Manger (SCCM) Remote Control can also be used. Further, third-party remote administration tools such as VNC, TeamViewer, LogMeIn, GoToMyPC, Bomgar, and many others will also work with DirectAccess ISATAP manage out.

Additional Information

ISATAP Recommendations for DirectAccess Deployments

DirectAccess Manage Out with ISATAP Fails on Windows 10 and Windows Server 2016 

DirectAccess Client Firewall Rule Configuration for ISATAP Manage Out

DirectAccess Manage Out and System Center Configuration Manager (SCCM)

Contact Me

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3 Important Advantages of Always On VPN over DirectAccess

3 Important Advantages of Always On VPN over DirectAccess Windows 10 Always On VPN hands-on training classes now forming. Details here.

Windows 10 Always On VPN provides seamless and transparent, always on remote network access similar to DirectAccess. The mechanics of how it is delivered and managed are fundamentally different, as I discussed here. Some of these changes will no doubt present challenges to our way of thinking, especially in the terms of client provisioning. However, Always On VPN brings along with it some important and significant advantages too.

No More NLS

A Network Location Server (NLS) is used for inside/outside detection by DirectAccess clients. By design, the NLS is reachable by DirectAccess machines only when they are on the internal network. NLS availability is crucial. If the NLS is offline or unreachable for any reason at all, DirectAccess clients on the internal network will mistakenly believe they are outside the network. In this scenario, the client will attempt to establish a DirectAccess connection even though it is inside. This often fails, leaving the DirectAccess client in a state where it cannot connect to any internal resources by name until the NLS is brought back online.

Always On VPN eliminates the frailty of NLS by using the DNS connection suffix for trusted network detection. When a network connection is established, an Always On VPN connection will not be established if the DNS connection suffix matches what the administrator has defined as the internal trusted network.

Full Support for IPv4

DirectAccess uses IPv6 exclusively for communication between remote DirectAccess clients and the DirectAccess server. IPv6 translation technologies allow for communication to internal IPv4 hosts. While this works for the vast majority of scenarios, there are still many challenges with applications that do not support IPv6.

Always On VPN supports both IPv4 and IPv6, so application incompatibility issues will be a thing of the past! With full support for IPv4, the need for IPv6 transition and translation technologies is eliminated. This reduces protocol overhead and improves network performance.

Infrastructure Independent

3 Important Advantages of Always On VPN over DirectAccess Windows servers are required to implement DirectAccess. Always On VPN can be implemented using Windows servers as well, but it isn’t a hard requirement. Always On VPN is implemented entirely on the Windows 10 client, which means any third-party VPN device can be used on the back end, including Cisco, Checkpoint, Juniper, Palo Alto, Fortinet, SonicWALL, F5, strongSwan, and others! This provides tremendous deployment flexibility, making it possible to mix and match backend infrastructure if required. For example, a Windows RRAS VPN server with Palo Alto and SonicWALL firewalls could all be implemented at the same time (using the Windows built-in VPN client). Importantly, making changes to VPN infrastructure is much less impactful and disruptive to clients in the field. VPN devices can be upgraded, replaced, and moved internally without requiring corresponding policy changes on the client.

Additional Information

Always On VPN and the Future of Microsoft DirectAccess 

5 Things DirectAccess Administrators Should Know about Always On VPN 

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Have questions about Windows 10 Always On VPN? Interested in learning more about this new solution? Fill out the form below and I’ll get in touch with you.

Deployment Considerations for DirectAccess on Amazon Web Services (AWS)

Organizations are rapidly deploying Windows server infrastructure with public cloud providers such as Amazon Web Services (AWS) and Microsoft Azure. With traditional on-premises infrastructure now hosted in the cloud, DirectAccess is also being deployed there more commonly.

Supportability

Interestingly, Microsoft has expressly stated that DirectAccess is not formally supported on their own public cloud platform, Azure. However, there is no formal statement of non-support for DirectAccess hosted on other non-Microsoft public cloud platforms. With supportability for DirectAccess on AWS unclear, many companies are taking the approach that if it isn’t unsupported, then it must be supported. I’d suggest proceeding with caution, as Microsoft could issue formal guidance to the contrary in the future.

DirectAccess on AWS

Deploying DirectAccess on AWS is similar to deploying on premises, with a few notable exceptions, outlined below.

IP Addressing

It is recommended that an IP address be exclusively assigned to the DirectAccess server in AWS, as shown here.

Deployment Considerations for DirectAccess on Amazon Web Services (AWS)

Prerequisites Check

When first configuring DirectAccess, the administrator will encounter the following warning message.

“The server does not comply with some DirectAccess prerequisites. Resolve all issues before proceed with DirectAccess deployment.”

The warning message itself states that “One or more network adapters should be configured with a static IP address. Obtain a static address and assign it to the adapter.

Deployment Considerations for DirectAccess on Amazon Web Services (AWS)

IP addressing for virtual machines are managed entirely by AWS. This means the DirectAccess server will have a DHCP-assigned address, even when an IP address is specified in AWS. Assigning static IP addresses in the guest virtual machine itself is also not supported. However, this warning message can safely be ignored.

No Support for Load Balancing

It is not possible to create load-balanced clusters of DirectAccess servers for redundancy or scalability on AWS. This is because enabling load balancing for DirectAccess requires the IP address of the DirectAccess server be changed in the operating system, which is not supported on AWS. To eliminate single points of failure in the DirectAccess architecture or to add additional capacity, multisite must be enabled. Each additional DirectAccess server must be provisioned as an individual entry point.

Network Topology

DirectAccess servers on AWS can be provisioned with one or two network interfaces. Using two network interfaces is recommended, with the external network interface of the DirectAccess server residing in a dedicated perimeter/DMZ network. The external network interface must use either the Public or Private Windows firewall profile. DirectAccess will not work if the external interface uses the Domain profile. For the Public and Private profile to be enabled, domain controllers must not be reachable from the perimeter/DMZ network. Ensure the perimeter/DMZ network cannot access the internal network by restricting network access in EC2 using a Security Group, or on the VPC using a Network Access Control List (ACL) or custom route table settings.

External Connectivity

A public IPv4 address must be associated with the DirectAccess server in AWS. There are several ways to accomplish this. The simplest way is to assign a public IPv4 address to the virtual machine (VM). However, a public IP address can only be assigned to the VM when it is deployed initially and cannot be added later. Alternatively, an Elastic IP can be provisioned and assigned to the DirectAccess server at any time.

An ACL must also be configured for the public IP that restricts access from the Internet to only inbound TCP port 443. To provide additional protection, consider deploying an Application Delivery Controller (ADC) appliance like the Citrix NetScaler or F5 BIG-IP to enforce client certificate authentication for DirectAccess clients.

Network Location Server (NLS)

If an organization is hosting all of its Windows infrastructure in AWS and all clients will be remote, Network Location Server (NLS) availability becomes much less critical than with traditional on-premises deployments. For cloud-only deployments, hosting the NLS on the DirectAccess server is a viable option. It eliminates the need for dedicated NLS, reducing costs and administrative overhead. If multisite is configured, ensure that the NLS is not using a self-signed certificate, as this is unsupported.

Deployment Considerations for DirectAccess on Amazon Web Services (AWS)

However, for hybrid cloud deployments where on-premises DirectAccess clients share the same internal network with cloud-hosted DirectAccess servers, it is recommended that the NLS be deployed on dedicated, highly available servers following the guidance outlined here and here.

Client Provisioning

All supported DirectAccess clients will work with DirectAccess on AWS. If the domain infrastructure is hosted exclusively in AWS, provisioning clients can be performed using Offline Domain Join (ODJ). Provisioning DirectAccess clients using ODJ is only supported in Windows 8.x/10. Windows 7 clients cannot be provisioned using ODJ and must be joined to the domain using another form of remote network connectivity such as VPN.

Additional Resources

DirectAccess No Longer Supported in Microsoft Azure

Microsoft Server Software Support for Azure Virtual Machines

DirectAccess Network Location Server (NLS) Guidance

DirectAccess Network Location Server (NLS) Deployment Considerations for Large Enterprises

Provisioning DirectAccess Clients using Offline Domain Join (ODJ)

DirectAccess SSL Offload and IP-HTTPS Preauthentication with Citrix NetScaler

DirectAccess SSL Offload and IP-HTTPS Preauthentication with F5 BIG-IP

Planning and Implementing DirectAccess with Windows Server 2016 Video Training Course

Implementing DirectAccess with Windows Server 2016 Book