Always On VPN and RRAS in Azure

Always On VPN and RRAS in AzureWhen deploying Windows 10 Always On VPN, it may be desirable to host the VPN server in Microsoft’s Azure public cloud. Recently I wrote about Always On VPN deployment options in Azure, and in that post I indicated that deploying Windows Server and the Routing and Remote Access Service (RRAS) was one of those options. Although not formally supported by Microsoft, RRAS is often deployed in Azure because it is cost-effective, easy to manage, and provides flexible scalability.

Supportability

It’s important to state once again that although it is possible to successfully deploy Windows Server with RRAS in Azure to support Always On VPN, as of this writing it is not a formally supported workload. If the administrator makes the decision to deploy RRAS in Azure, they must also accept that Microsoft may refuse to assist with troubleshooting in this specific deployment scenario.

Always On VPN and RRAS in Azure

Reference: https://support.microsoft.com/en-us/help/2721672/microsoft-server-software-support-for-microsoft-azure-virtual-machines

Azure Prerequisites

The configuration of RRAS is identical to on-premises, with a few additional steps required by Azure infrastructure.

Windows Server

RRAS can be configured on any Windows Server virtual machine supported in Microsoft Azure. As with on-premises deployments, Server GUI and Core are supported. Domain-join is optional. The server can be deployed with one network interface or two.

Public IP

A public IP address must be assigned to the VPN server’s external network interface, or the internal interface if the VPN server is configured with a single network adapter. The IP address can be static or dynamic. When using a dynamic IP address, configure a CNAME record in DNS that points to the name configured for the IP address in Azure. If using a static IP address, an A host record can be configured pointing directly to the IP address.

Network Security Group

A Network Security Group (NSG) must be configured and assigned to the VPN server’s external or public-facing network interface that allows the following protocols and ports inbound.

  • TCP port 443 (SSTP)
  • UDP port 500 (IKEv2)
  • UDP port 4500 (IKEv2 NAT traversal)

RRAS in Azure

Below are the infrastructure requirements for supporting Windows Server RRAS VPN in Azure.

Client IP Subnet

Static IP address pool assignment must be used with RRAS. Using DHCP for VPN client IP address assignment in Azure is not supported and will not work. The IP subnet assigned to VPN clients by RRAS must be unique and not overlap with any existing Azure VNet subnets. If more than one VPN server is deployed, each server should be configured to assign a unique subnet for its clients.

IP Forwarding

IP forwarding must be enabled on the VPN server’s internal network interface. Follow the steps below to enable IP forwarding.

1. In the Azure portal, open the properties page for the internal network interface for the VPN server.
2. Click IP configurations in the navigation pane.
3. Click Enabled next to IP forwarding.
4. Click Save.

Always On VPN and RRAS in Azure

Routing

Azure must be configured to route IP traffic from VPN clients back to the VPN server. Follow the steps below to create and assign a routing table in Azure.

1. Click Create Resource.
2. Enter “Route Table” in the search field and press Enter.
3. Click Route Table.
4. Click Create.
5. Enter a descriptive name for the route table in the Name field.
6. Choose an appropriate subscription from the Subscription drop-down list.
7. Select the resource group where the VPN server(s) reside.
8. Select the best location to deploy the route table resource from the Location drop-down list.
9. If the administrator wants to have the VPN client IP subnet route information published automatically, select Enabled for Virtual network gateway route propagation.
10. Click Create.

Always On VPN and RRAS in Azure

Once complete, follow the steps below to define the route for VPN clients.

1. Open the properties page for the route table.
2. Click Routes in the navigation pane.
3. Click Add.
4. Enter a descriptive name in the Route name filed.
5. Enter the IP subnet assigned to VPN clients in the Address prefix field.
6. Select Virtual appliance from the Next hop type drop-down list.
7. Enter the IPv4 address assigned to the VPN server’s internal network interface in the Next hop address field.
8. Click Ok.
9. Repeat the steps above for each VPN server configured in Azure.

Always On VPN and RRAS in Azure

Finally, follow the steps below to assign the route table to an Azure VNet subnet.

1. Open the properties page for the route table.
2. Click Subnets in the navigation pane.
3. Click Associate.
4. Click Virtual network.
5. Choose the appropriate Azure VNet.
6. Click Subnet.
7. Choose an Azure VNet subnet to assign the route table to.
8. Click Ok.
9. Repeat the steps above to assign the route table to any Azure VNet subnet that must be accessible by VPN clients. If VPN clients need access to on-premises resources via Azure site-to-site gateway, assign the route table to the Azure VPN gateway subnet.

Always On VPN and RRAS in Azure

Note: Azure only supports the assignment of one route table per subnet. If a route table is currently assigned, the VPN client subnet route can be added to an existing route table, if necessary.

Summary

Administrators have many choices when it comes to support Always On VPN connections hosted in Azure. RRAS on Windows Server can be an effective solution, assuming you can live without formal support. If having a formally supported solution is a hard requirement, consider deploying Always On VPN using the native Azure VPN gateway or another third-part Network Virtual Appliance (NVA).

Additional Information

Azure deployment options

Always On VPN Options for Azure Deployments

Always On VPN Options for Azure DeploymentsOrganizations everywhere are rapidly adopting Microsoft Azure public cloud infrastructure to extend or replace their existing datacenter. As traditional on-premises workloads are migrated to the cloud, customers are looking for options to host VPN services there as well.

Windows Server

Windows Server with the Routing and Remote Access Service (RRAS) installed is a popular choice for on-premises Always On VPN deployments. Intuitively it would make sense to deploy Windows Server and RRAS in Azure as well. However, at the time of this writing, RRAS is not a supported workload on Windows Server in Azure.

Always On VPN Options for Azure Deployments

Reference: https://support.microsoft.com/en-us/help/2721672/microsoft-server-software-support-for-microsoft-azure-virtual-machines/

Although explicitly unsupported, it is possible to deploy Windows Server and RRAS in Azure for Always On VPN. In my experience it works well and can be an option for organizations willing to forgo formal support by Microsoft.

Azure Gateway

Options for supporting Always On VPN connections using native Azure VPN infrastructure depend on the type of VPN gateway chosen.

VPN Gateway

The Azure VPN Gateway can be configured to support client-based (point-to-site) VPN. With some additional configuration it can be used to support Windows 10 Always On VPN deployments. Azure VPN gateway supports both IKEv2 and SSTP VPN protocols for client connections. The Azure VPN gateway has some limitations though. Consider the following:

  • A route-based VPN gateway is required
  • A maximum of 1000 concurrent IKEv2 connections are supported when using the VpnGw3 or VpnGw3AZ SKUs (2000 supported in active/active mode)
  • A maximum of 128 concurrent SSTP connections are supported on all gateway SKUs (256 supported in active/active mode)

Virtual WAN

Azure Virtual WAN is the future of remote connectivity for Azure. It includes support for client-based VPN (currently in public preview at the time of this writing), but only supports IKEv2 and OpenVPN VPN protocols for client connections. SSTP is not supported at all. Further, OpenVPN is not supported for Windows 10 Always On VPN, leaving IKEv2 as the only option, which poses some potential operational challenges. Virtual WAN offer much better scalability though, supporting up to 10,000 concurrent client-based VPN connections.

Virtual Appliance

The most supportable option for hosting VPN services in Azure for Windows 10 Always On VPN is to deploy a third-party Network Virtual Appliance (NVA). They are available from a variety of vendors including Cisco, Check Point, Palo Alto Networks, Fortinet, and many others. To support Windows 10 Always On VPN, the NVA vendor must either support IKEv2 for client-based VPN connections or have a Universal Windows Platform (UWP) VPN plug-in client available from the Microsoft store. Click here to learn more about Always On VPN and third-party VPN devices.

Note: Be careful when choosing an NVA as some vendors support IKEv2 only for site-to-site VPN, but not client-based VPN!

Hybrid Deployments

For organizations with hybrid cloud deployments (infrastructure hosted on-premises and in Azure), there are several options for choosing the best location to deploy VPN services. In general, it is recommended that client VPN connections be established nearest the resources accessed by remote clients. However, having VPN servers hosted both on-premises and in Azure is fully supported. In this scenario Azure Traffic Manager can be configured to intelligently route VPN connections for remote clients.

NetMotion Mobility

The NetMotion Mobility purpose-built enterprise VPN is a popular replacement for Microsoft DirectAccess. It is also an excellent alternative for enterprise organizations considering a migration to Always On VPN. It is a software-based solution that can be deployed on Windows Server and is fully supported running in Microsoft Azure. It offers many advanced features and capabilities not included in other remote access solutions.

Summary

Administrators have many options for deploying VPN servers in Azure to support Windows 10 Always On VPN. Windows Server and RRAS is the simplest and most cost-effective option, but it is not formally supported by Microsoft. Azure VPN gateway is an interesting alternative but lacks enough capacity for larger deployments. Azure Virtual WAN is another option but has limited protocol support. Deploying an NVA is a good choice, and NetMotion Mobility is an excellent alternative to both DirectAccess and Always On VPN that is software-based and fully supported in Azure.

Additional Information

Windows 10 Always On VPN with Azure Gateway

Windows 10 Always On VPN and Third-Party VPN Devices

Windows 10 Always On VPN and Windows Server Routing and Remote Access Service (RRAS)

Windows 10 Always On VPN IKEv2 Features and Limitations

Windows 10 Always On VPN Multisite with Azure Traffic Manager

Comparing DirectAccess and NetMotion Mobility

Deploying NetMotion Mobility in Microsoft Azure

 

 

Always On VPN and Azure MFA ESTS Token Error

Always On VPN and Azure MFA ESTS Token ErrorConfiguring Multifactor Authentication (MFA) is an excellent way to ensure the highest level of assurance for Always On VPN users. Azure MFA is widely deployed and commonly integrated with Windows Server Network Policy Server (NPS) using the NPS Extension for Azure MFA. Azure MFA has a unique advantage over many other MFA providers in that it supports MFA when using Protected Extensible Authentication Protocol (PEAP). This makes Azure MFA the solution of choice for integrating with Windows 10 Always On VPN deployments using client certificate authentication, a recommended security configuration best practice.

NPS Configuration

Installing and configuring the NPS extension for Azure MFA is straightforward. Configuration guidance from Microsoft can be found here.

Connection Issues

After installing the NPS extension for Azure MFA, administrators may find that Always On VPN connections fail and the user is never challenged for authentication. The connection eventually times out and returns the following error message.

“A connection to the remote computer could not be established, so the port used for this connection was closed.”

Always On VPN and Azure MFA ESTS Token Error

In addition, the Application event log on the Windows 10 client contains an Event ID 20221 from the RasClient source that includes the following error message.

“The user [username] dialed a connection named [connection] which has failed. The error code returned on failure is 0.”

Always On VPN and Azure MFA ESTS Token Error

NPS Event Log

Reviewing the event logs on the NPS server reveals more information. The Security event log contains an Event ID 6274 from the Microsoft Windows security auditing source that includes the following error message.

“Network Policy Server discarded the request for a user. Contact the Network Policy Administrator for more information.”

Always On VPN and Azure MFA ESTS Token Error

ESTS Token Error

Digging deeper in the operational event log on the NPS server, the AuthZAdminCh log (Applications and Services Logs > Microsoft > AzureMfa > AuthZ) contains an Event ID 3 from the AuthZ source indicating an ESTS_TOKEN_ERROR message.

Always On VPN and Azure MFA ESTS Token Error

Troubleshooting ESTS Token Error

Follow the steps below to troubleshoot the ESTS_TOKEN_ERROR.

Prerequisites

Ensure that all prerequisites are met. Validate the user is being synced to Azure Active Directory and that it is properly licensed for Azure MFA.

Certificates

As part of the NPS extension configuration, a certificate is created on the NPS server that is uploaded to Azure Active Directory. To validate the certificate was created and uploaded correctly, follow the troubleshooting guidance found here.

Enterprise Applications

The Azure Multi-Factor Auth Client and the Azure Multi-Factor Auth Connector enterprise applications must be enabled to support the NPS extension for Azure MFA. To confirm they are enabled, open an elevated PowerShell command window on the server where the Azure AD Connector is installed and run the following PowerShell commands.

Import-Module MSOnline
Connect-MsolService

Get-MsolServicePrincipal -AppPrincipalId “981f26a1-7f43-403b-a875-f8b09b8cd720” | Select-Object DisplayName, AccountEnabled

Get-MsolServicePrincipal -AppPrincipalId “1f5530b3-261a-47a9-b357-ded261e17918” | Select-Object DisplayName, AccountEnabled

Always On VPN and Azure MFA ESTS Token Error

If either or both enterprise applications are not enabled, enable them using the following PowerShell commands.

Set-MsolServicePrincipal -AppPrincipalId “981f26a1-7f43-403b-a875-f8b09b8cd720” -AccountEnabled $True

Set-MsolServicePrincipal -AppPrincipalId “1f5530b3-261a-47a9-b357-ded261e17918” -AccountEnabled $True

Once complete, restart the IAS service on the NPS server using the following PowerShell command.

Restart-Service IAS -PassThru

Additional Information

Windows 10 Always On VPN Network Policy Server (NPS) Load Balancing Strategies

Deploy Windows 10 Always On VPN with Microsoft Intune

Windows 10 Always On VPN Hands-On Training Classes Now Available

Always On VPN Updates to Improve Connection Reliability

Always On VPN Updates to Improve Connection ReliabilityA longstanding issue with Windows 10 Always On VPN is that of VPN tunnel connectivity reliability and device tunnel/user tunnel interoperability. Many administrators have reported that Always On VPN connections fail to establish automatically at times, that only one tunnel comes up at a time (user tunnel or device tunnel, but not both), or that VPN tunnels fail to establish when coming out of sleep or hibernate modes. Have a look at the comments on this post and you’ll get a good understanding of the issues with Always On VPN.

Recent Updates

The good news is that most of these issues have been resolved with recent updates to Windows 10 1803 and 1809. Specifically, the February 19, 2019 update for Windows 10 1803 (KB4487029) and the March 1, 2019 update for Windows 10 1809 (KB4482887) include fixes to address these known issues. Administrators are encouraged to deploy Windows 10 1803 with the latest updates applied when implementing Always On VPN. Windows 10 1809 with the latest updates applied is preferred though.

Persistent Issues

Although initial reports are favorable for these updates and based on my experience the effectiveness and reliability of Windows 10 Always On VPN is greatly improved, there have still been some reports of intermittent VPN tunnel establishment failures.

Possible Causes

During my testing, after applying the updates referenced earlier both device tunnel and user tunnel connections are established much more consistently than before the updates were applied. I did encounter some issues, however. Specifically, when coming out of sleep or hibernate, VPN connections would fail to establish. Occasionally VPN connections would fail after a complete restart.

NCSI

After further investigation it was determined that the connectivity failure was caused by the Network Connectivity Status Indicator (NCSI) probe failing, causing Windows to report “No Internet access”.

Always On VPN Updates to Improve Connection Reliability

Cisco Umbrella Roaming Client

In this instance the NCSI probe failure was caused by the Cisco Umbrella Roaming Client installed and running on the device. The Umbrella Roaming Client is security software that provides client protection by monitoring and filtering DNS queries. It operates by configuring a DNS listener on the loopback address. NCSI probes are known to fail when the DNS server is running on a different interface than is being tested.

Resolution

Microsoft released a fix for this issue in Windows 10 1709. The fix involves changing a group policy setting to disable interface binding when perform DNS lookups by the NCSI. You can enable this setting via Active Directory group policy by navigating to Computer Configuration > Administrative Templates > Network > Network Connectivity Status Indicator > Specify global DNS. Select Enabled and check the option to Use global DNS, as shown here.

Always On VPN Updates to Improve Connection Reliability

For testing purposes this setting can be enabled individual using the following PowerShell command.

New-ItemProperty -Path “HKLM:\SOFTWARE\Policies\Microsoft\Windows\NetworkConnectivityStatusIndicator\” -Name UseGlobalDNS -PropertyType DWORD -Value 1 -Force

Third-Party Software

As Always On VPN connectivity can be affected by NCSI, any third-party firewall or antivirus/antimalware solution could potentially introduce VPN connection instability. Observe NCSI operation closely when troubleshooting unreliable connections with Always On VPN.

Additional Information

Windows 10 1803 Update KB4487029

Windows 10 1809 Update KB4482887

Cisco Umbrella Roaming Client Limited Network Connectivity Warning

Network Connectivity Status Indicator (NCSI) Operation Explained

Always On VPN Device Tunnel Configuration using Intune

Always On VPN Device Tunnel Configuration using IntuneA while back I described in detail how to configure a Windows 10 Always On VPN device tunnel connection using PowerShell. While using PowerShell is fine for local testing, it obviously doesn’t scale well. In theory you could deploy the PowerShell script and XML file using System Center Configuration Manager (SCCM), but using Microsoft Intune is the recommended and preferred deployment method. However, as of this writing Intune does not support device tunnel configuration natively. The administrator must create a ProfileXML manually and use Intune to deploy it.

Device Tunnel Prerequisites

I outlined the Always On VPN device tunnel prerequisites in my previous post here. To summarize, the client must be running Windows 10 Enterprise edition and be domain-joined. It must also have a certificate issued by the internal PKI with the Client Authentication EKU in the local computer certificate store.

ProfileXML

To begin, create a ProfileXML for the device tunnel that includes the required configuration settings and parameters for your deployment. You can find a sample Windows 10 Always On VPN device tunnel ProfileXML here.

Note: Be sure to define a custom IPsec policy in ProfileXML for the device tunnel. The default security settings for the IKEv2 protocol (required for the device tunnel) are quite poor. Details here.

Intune Deployment

Open the Intune management console and follow the steps below to deploy an Always On VPN device tunnel using Microsoft Intune.

Create Profile

1. Navigate to the Intune portal.
2. Click Device configuration.
3. Click Profiles.
4. Click Create profile.

Define Profile Settings

1. Enter a name for the VPN connection in the Name field.
2. Enter a description for the VPN connection in the Description field (optional).
3. Select Windows 10 and later from the Platform drop-down list.
4. Select Custom from the Profile type drop-down list.

Always On VPN Device Tunnel Configuration using Intune

Define Custom OMA-URI Settings

1. On the Custom OMA-URI Settings blade click Add.
2. Enter a name for the device tunnel in the Name field.
3. Enter a description for the VPN connection in the Description field (optional).
4. Enter the URI for the device tunnel in the OMA-URI field using the following syntax. If the profile name includes spaces they must be escaped, as shown here.

./Device/Vendor/MSFT/VPNv2/Example%20Profile%Name/ProfileXML

5. Select String (XML file) from the Data Type drop-down list.
6. Click the folder next to the Select a file field and chose the ProfileXML file created previously.
7. Click Ok twice and then click Create.

Always On VPN Device Tunnel Configuration using Intune

Assign Profile

Follow the steps below to assign the Always On VPN device tunnel profile to the appropriate device group.

1. Click Assignments.
2. Click Select groups to include.
3. Select the group that includes the Windows 10 client devices.
4. Click Select.
5. Click Save.

Always On VPN Device Tunnel Configuration using Intune

Demonstration Video

A video demonstration of the steps outlined above can be viewed here.

Additional Information

Windows 10 Always On VPN Device Tunnel Configuration using PowerShell

Windows 10 Always On VPN IKEv2 Security Configuration

Deleting a Windows 10 Always On VPN Device Tunnel

Windows 10 Always On VPN Device Tunnel Missing in the UI

Video: Deploying Windows 10 Always On VPN User Tunnel with Microsoft Intune

Always On VPN Multisite with Azure Traffic Manager

Always On VPN Multisite with Azure Traffic ManagerEliminating single points of failure is crucial to ensuring the highest levels of availability for any remote access solution. For Windows 10 Always On VPN deployments, the Windows Server 2016 Routing and Remote Access Service (RRAS) and Network Policy Server (NPS) servers can be load balanced to provide redundancy and high availability within a single datacenter. Additional RRAS and NPS servers can be deployed in another datacenter or in Azure to provide geographic redundancy if one datacenter is unavailable, or to provide access to VPN servers based on the location of the client.

Multisite Always On VPN

Unlike DirectAccess, Windows 10 Always On VPN does not natively include support for multisite. However, enabling multisite geographic redundancy can be implemented using Azure Traffic Manager.

Azure Traffic Manager

Traffic Manager is part of Microsoft’s Azure public cloud solution. It provides Global Server Load Balancing (GSLB) functionality by resolving DNS queries for the VPN public hostname to an IP address of the most optimal VPN server.

Advantages and Disadvantages

Using Azure Traffic manager has some benefits, but it is not with some drawbacks.

Advantages – Azure Traffic Manager is easy to configure and use. It requires no proprietary hardware to procure, manage, and support.

Disadvantages – Azure Traffic Manager offers only limited health check options. Azure Traffic Manager’s HTTPS health check only accepts HTTP 200 OK responses as valid. Most TLS-based VPNs will respond with an HTTP 401 Unauthorized, which Azure Traffic Manager considers “degraded”. The only option for endpoint monitoring is a simple TCP connection to port 443, which is a less accurate indicator of endpoint availability.

Note: This scenario assumes that RRAS with Secure Socket Tunneling Protocol (SSTP) or another third-party TLS-based VPN server is in use. If IKEv2 is to be supported exclusively, it will still be necessary to publish an HTTP or HTTPS-based service for Azure Traffic Manager to monitor site availability.

Traffic Routing Methods

Azure Traffic Manager provide four different methods for routing traffic.

Priority – Select this option to provide active/passive failover. A primary VPN server is defined to which all traffic is routed. If the primary server is unavailable, traffic will be routed to another backup server.

Weighted – Select this option to provide active/active failover. Traffic is routed to all VPN servers equally, or unequally if desired. The administrator defines the percentage of traffic routed to each server.

Performance – Select this option to route traffic to the VPN server with the lowest latency. This ensures VPN clients connect to the server that responds the quickest.

Geographic – Select this option to route traffic to a VPN server based on the VPN client’s physical location.

Configure Azure Traffic Manager

Open the Azure management portal and follow the steps below to configure Azure Traffic Manager for multisite Windows 10 Always On VPN.

Create a Traffic Manager Resource

  1. Click Create a resource.
  2. Click Networking.
  3. Click Traffic Manager profile.

Create a Traffic Manager Profile

  1. Enter a unique name for the Traffic Manager profile.
  2. Select an appropriate routing method (described above).
  3. Select a subscription.
  4. Create or select a resource group.
  5. Select a resource group location.
  6. Click Create.

Always On VPN Multisite with Azure Traffic Manager

Important Note: The name of the Traffic Manager profile cannot be used by VPN clients to connect to the VPN server, since a TLS certificate cannot be obtained for the trafficmanager.net domain. Instead, create a CNAME DNS record that points to the Traffic Manager FQDN and ensure that name matches the subject or a Subject Alternative Name (SAN) entry on the VPN server’s TLS and/or IKEv2 certificates.

Endpoint Monitoring

Open the newly created Traffic Manager profile and perform the following tasks to enable endpoint monitoring.

  1. Click Configuration.
  2. Select TCP from the Protocol drop-down list.
  3. Enter 443 in the Port field.
  4. Update any additional settings, such as DNS TTL, probing interval, tolerated number of failures, and probe timeout, as required.
  5. Click Save.

Always On VPN Multisite with Azure Traffic Manager

Endpoint Configuration

Follow the steps below to add VPN endpoints to the Traffic Manager profile.

  1. Click Endpoints.
  2. Click Add.
  3. Select External Endpoint from the Type drop-down list.
  4. Enter a descriptive name for the endpoint.
  5. Enter the Fully Qualified Domain Name (FQDN) or the IP address of the first VPN server.
  6. Select a geography from the Location drop-down list.
  7. Click OK.
  8. Repeat the steps above for any additional datacenters where VPN servers are deployed.

Always On VPN Multisite with Azure Traffic Manager

Summary

Implementing multisite by placing VPN servers is multiple physical locations will ensure that VPN connections can be established successfully even when an entire datacenter is offline. In addition, active/active scenarios can be implemented, where VPN client connections can be routed to the most optimal datacenter based on a variety of parameters, including current server load or the client’s current location.

Additional Information

Windows 10 Always On VPN Hands-On Training Classes

 

Cloudflare Public DNS Resolver Now Available

Cloudflare Public DNS Resolver Now AvailableCloudflare has become a nearly ubiquitous cloud service provider in recent years, fronting many of the busiest web sites on the Internet. They provide tremendous value both in terms of security and performance for their customers. They have a wide array of solutions designed to provide better security, including optimized SSL/TLS configuration and Web Application Firewall (WAF) capabilities. Their DDoS mitigation service is second to none, and their robust Content Delivery Network (CDN) ensures optimal loading of content for web sites anywhere in the world.

Public DNS Resolver

Recently Cloudflare announced their first consumer service, a public DNS resolver that is free for general use. It offers exceptional performance and supports many of the latest DNS security and privacy enhancements such as DNS-over-TLS. Cloudflare has also pledged not to write DNS queries to disk at all and not to store them for more than 24 hours to further ensure privacy for their customers.

Cloudflare Public DNS Resolver Now Available

DNS Security Controls

What Cloudflare DNS is lacking today is granular security enforcement to provide additional protection for client computers outside the firewall. For example, public DNS resolvers from OpenDNS and Quad9 have built-in security features that use threat intelligence to identify and block DNS name resolution requests for domains that are known to be malicious or unsafe. OpenDNS has the added benefit of providing more granularity for setting policy, allowing administrators to select different filtering levels and optionally to create custom policies to allow or block individually selected categories. With OpenDNS, security administrators can also manage domains individually by manually assigning allow or block to specific, individual domains as necessary.

Recommended Use Cases

Cloudflare DNS clearly offers the best performance of all public DNS resolvers today, which makes it a good candidate for servers that rely heavily on DNS for operation. Mail servers come to mind immediately, but any system that performs many forward and/or reverse DNS lookups would benefit from using Cloudflare DNS. Cloudflare DNS can also be used by client machines where better performance and enhanced privacy are desired.

Quad9 DNS is a good choice for client computers where additional security is required. OpenDNS is the best choice where the highest level of security is required, and where granular control of security and web filtering policies is necessary.

Additional Information

Cloudflare DNS
Quad9 DNS
OpenDNS
Dnsperf.com

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

DirectAccess and Azure Multifactor Authentication

Introduction

DirectAccess and Azure Multifactor AuthenticationDirectAccess can be configured to enforce strong user authentication using smart cards or one-time passwords (OTP). This provides the highest level of assurance for remote users connecting to the internal network via DirectAccess. OTP solutions are commonly used because they require less administration and are more cost effective than typical smart card implementations. Most OTP solutions will integrate with DirectAccess as long as they support Remote Access Dial-In User Service (RADIUS).

DirectAccess and Azure Multifactor Authentication

Azure Authentication-as-a-Service

Azure Multifactor Authentication (MFA) is a popular OTP provider used to enable strong user authentication for a variety of platforms, including web sites and client-based VPN. Unfortunately, it doesn’t work with DirectAccess. This is because Azure MFA uses a challenge/response method for which DirectAccess does not support. To use OTP with DirectAccess, the user must be able to enter their PIN and OTP immediately when prompted. There is no provision to begin the authentication process and wait for a response from the OTP provider.

PointSharp ID Multifactor Authentication

An excellent alternative to Azure MFA is PointSharp ID. PointSharp is a powerful OTP platform that integrates easily with DirectAccess. It is also very flexible, allowing for more complex authentication schemes for those workloads that support it, such as Exchange and Skype for Business.

DirectAccess and Azure Multifactor AuthenticationEvaluate PointSharp

You can download a fully-functional trial version of PointSharp ID here (registration required). The PointSharp ID and DirectAccess integration guide with detailed step-by-step instructions for configuring DirectAccess and PointSharp ID can be downloaded here. Consulting services are also available to assist with integrating PointSharp ID with DirectAccess, VPN, Exchange, Skype for Business, Remote Desktop Services, or any other solution that requires strong user authentication. More information about consulting services can be found here.

Additional Information

PointSharp Multifactor Authentication
Configure DirectAccess with OTP Authentication
DirectAccess Consulting Services
Implementing DirectAccess with Windows Server 2016

DirectAccess No Longer Supported in Microsoft Azure

DirectAccess No Longer Supported on Windows Server in AzureMicrosoft has historically not supported DirectAccess running on Windows Server in the Microsoft Azure public cloud. In the past, this was due to limitations imposed by the underlying cloud infrastructure, as I documented here. When Microsoft moved from the old service manager model (classic) to the newer resource manager infrastructure, many of the issues that prevented the DirectAccess workload from being stable were resolved. There are still some fundamental limitations to deploying DirectAccess in Azure as I documented here, but for the most part it was a workable solution. In fact, Microsoft even updated their support statement for DirectAccess on Azure, quietly removing it from the unsupported roles list in July 2016.

Sadly, Microsoft has reversed their decision on the support of DirectAccess in Azure. As many of you have noticed or commented on some of my posts, Microsoft recently added clarification on support for remote access on Windows Server in Azure, explicitly indicating that DirectAccess was not included in Remote Access support.

Reference: https://support.microsoft.com/en-us/kb/2721672

You’ll be glad to know that DirectAccess is indeed supported in Amazon’s public cloud infrastructure, Amazon Web Services (AWS). I’ll be drafting some guidance for deploying DirectAccess in AWS soon. Stay tuned!

Additional Resources

Azure Resource Manager vs. Classic Deployment: Understand Deployment Models and the State of your Resources

Deploying DirectAccess in Microsoft Azure

Implementing DirectAccess in Windows Server 2016 Book

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