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Use Azure Firewall to protect Azure Virtual Desktop deployments

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Azure Virtual Desktop is a desktop and app virtualization service that runs on Azure. When an end user connects to an Azure Virtual Desktop environment, their session is run by a host pool. A host pool is a collection of Azure virtual machines that register to Azure Virtual Desktop as session hosts. These virtual machines run in your virtual network and are subject to the virtual network security controls. They need outbound Internet access to the Azure Virtual Desktop service to operate properly and might also need outbound Internet access for end users. Azure Firewall can help you lock down your environment and filter outbound traffic.

Azure Virtual Desktop architecture

Follow the guidelines in this article to provide extra protection for your Azure Virtual Desktop host pool using Azure Firewall.

Prerequisites

  • A deployed Azure Virtual Desktop environment and host pool.
  • An Azure Firewall deployed with at least one Firewall Manager Policy.
  • DNS and DNS Proxy enabled in the Firewall Policy to use FQDN in Network Rules.

For more information, see Tutorial: Create a host pool by using the Azure portal

To learn more about Azure Virtual Desktop environments see Azure Virtual Desktop environment.

Host pool outbound access to Azure Virtual Desktop

The Azure virtual machines you create for Azure Virtual Desktop must have access to several Fully Qualified Domain Names (FQDNs) to function properly. Azure Firewall provides an Azure Virtual Desktop FQDN Tag to simplify this configuration. Use the following steps to allow outbound Azure Virtual Desktop platform traffic:

You'll need to create an Azure Firewall Policy and create Rule Collections for Network Rules and Applications Rules. Give the Rule Collection a priority and an allow or deny action. In order to identify a specific AVD Host Pool as "Source" in the tables below, IP Group can be created to represent it.

Create network rules

Based on the Azure Virtual Desktop (AVD) reference article, these are the mandatory rules to allow outbound access to the control plane and core dependent services:

Name Source type Source Protocol Destination ports Destination type Destination
Rule Name IP Address or Group IP Group or VNet or Subnet IP Address TCP 443 FQDN login.microsoftonline.com
Rule Name IP Address or Group IP Group or VNet or Subnet IP Address TCP 443 Service Tag WindowsVirtualDesktop, AzureFrontDoor.Frontend, AzureMonitor
Rule Name IP Address or Group IP Group or VNet or Subnet IP Address TCP, UDP 53 IP Address *
Rule name IP Address or Group IP Group or VNet or Subnet IP Address TCP 1688 IP address 20.118.99.224, 40.83.235.53 (azkms.core.windows.net)
Rule name IP Address or Group IP Group or VNet or Subnet IP Address TCP 1688 IP address 23.102.135.246 (kms.core.windows.net)
Rule name IP Address or Group IP Group or VNet or Subnet IP Address TCP 443 FQDN mrsglobalsteus2prod.blob.core.windows.net
Rule name IP Address or Group IP Group or VNet or Subnet IP Address TCP 443 FQDN wvdportalstorageblob.blob.core.windows.net
Rule name IP Address or Group IP Group or VNet or Subnet IP Address TCP 80 FQDN oneocsp.microsoft.com
Rule name IP Address or Group IP Group or VNet or Subnet IP Address TCP 80 FQDN www.microsoft.com

Note

Some deployments might not need DNS rules. For example, Azure Active Directory Domain controllers forward DNS queries to Azure DNS at 168.63.129.16.

Azure Virtual Desktop (AVD) official documentation reports the following Network rules as optional depending on the usage and scenario:

Name Source type Source Protocol Destination ports Destination type Destination
Rule Name IP Address or Group IP Group or VNet or Subnet IP Address UDP 123 FQDN time.windows.com
Rule Name IP Address or Group IP Group or VNet or Subnet IP Address TCP 443 FQDN login.windows.net
Rule Name IP Address or Group IP Group or VNet or Subnet IP Address TCP 443 FQDN www.msftconnecttest.com

Create application rules

Azure Virtual Desktop (AVD) official documentation reports the following Application rules as optional depending on the usage and scenario:

Name Source type Source Protocol Destination type Destination
Rule Name IP Address or Group VNet or Subnet IP Address Https:443 FQDN Tag WindowsUpdate, Windows Diagnostics, MicrosoftActiveProtectionService
Rule Name IP Address or Group VNet or Subnet IP Address Https:443 FQDN *.events.data.microsoft.com
Rule Name IP Address or Group VNet or Subnet IP Address Https:443 FQDN *.sfx.ms
Rule Name IP Address or Group VNet or Subnet IP Address Https:443 FQDN *.digicert.com
Rule Name IP Address or Group VNet or Subnet IP Address Https:443 FQDN *.azure-dns.com, *.azure-dns.net

Important

We recommend that you don't use TLS inspection with Azure Virtual Desktop. For more information, see the proxy server guidelines.

Azure Firewall Policy Sample

All the mandatory and optional rules mentioned above can be easily deployed a single Azure Firewall Policy using the template published at this link. Before deploying into production, it's highly recommended to review all the Network and Application rules defined, ensure alignment with Azure Virtual Desktop official documentation and security requirements.

Host pool outbound access to the Internet

Depending on your organization needs, you might want to enable secure outbound internet access for your end users. If the list of allowed destinations is well-defined (for example, for Microsoft 365 access), you can use Azure Firewall application and network rules to configure the required access. This routes end-user traffic directly to the internet for best performance. If you need to allow network connectivity for Windows 365 or Intune, see Network requirements for Windows 365 and Network endpoints for Intune.

If you want to filter outbound user internet traffic by using an existing on-premises secure web gateway, you can configure web browsers or other applications running on the Azure Virtual Desktop host pool with an explicit proxy configuration. For example, see How to use Microsoft Edge command-line options to configure proxy settings. These proxy settings only influence your end-user internet access, allowing the Azure Virtual Desktop platform outbound traffic directly via Azure Firewall.

Control user access to the web

Admins can allow or deny user access to different website categories. Add a rule to your Application Collection from your specific IP address to web categories you want to allow or deny. Review all the web categories.

Next steps