Tutorial: Deploy and configure Azure Firewall in a hybrid network using the Azure portal

When you connect your on-premises network to an Azure virtual network to create a hybrid network, the ability to control access to your Azure network resources is an important part of an overall security plan.

You can use Azure Firewall to control network access in a hybrid network using rules that define allowed and denied network traffic.

For this tutorial, you create three virtual networks:

  • VNet-Hub - the firewall is in this virtual network.
  • VNet-Spoke - the spoke virtual network represents the workload located on Azure.
  • VNet-Onprem - The on-premises virtual network represents an on-premises network. In an actual deployment, it can be connected by either a VPN or ExpressRoute connection. For simplicity, this tutorial uses a VPN gateway connection, and an Azure-located virtual network is used to represent an on-premises network.

Firewall in a hybrid network

In this tutorial, you learn how to:

  • Declare the variables
  • Create the firewall hub virtual network
  • Create the spoke virtual network
  • Create the on-premises virtual network
  • Configure and deploy the firewall
  • Create and connect the VPN gateways
  • Peer the hub and spoke virtual networks
  • Create the routes
  • Create the virtual machines
  • Test the firewall

If you want to use Azure PowerShell instead to complete this procedure, see Deploy and configure Azure Firewall in a hybrid network using Azure PowerShell.

Prerequisites

A hybrid network uses the hub-and-spoke architecture model to route traffic between Azure VNets and on-premise networks. The hub-and-spoke architecture has the following requirements:

  • Set AllowGatewayTransit when peering VNet-Hub to VNet-Spoke. In a hub-and-spoke network architecture, a gateway transit allows the spoke virtual networks to share the VPN gateway in the hub, instead of deploying VPN gateways in every spoke virtual network.

    Additionally, routes to the gateway-connected virtual networks or on-premises networks will automatically propagate to the routing tables for the peered virtual networks using the gateway transit. For more information, see Configure VPN gateway transit for virtual network peering.

  • Set UseRemoteGateways when you peer VNet-Spoke to VNet-Hub. If UseRemoteGateways is set and AllowGatewayTransit on remote peering is also set, the spoke virtual network uses gateways of the remote virtual network for transit.

  • To route the spoke subnet traffic through the hub firewall, you can use a User Defined route (UDR) that points to the firewall with the Virtual network gateway route propagation option disabled. The Virtual network gateway route propagation disabled option prevents route distribution to the spoke subnets. This prevents learned routes from conflicting with your UDR. If you want to keep Virtual network gateway route propagation enabled, make sure to define specific routes to the firewall to override those that are published from on-premises over BGP.

  • Configure a UDR on the hub gateway subnet that points to the firewall IP address as the next hop to the spoke networks. No UDR is required on the Azure Firewall subnet, as it learns routes from BGP.

See the Create Routes section in this tutorial to see how these routes are created.

Note

Azure Firewall must have direct Internet connectivity. If your AzureFirewallSubnet learns a default route to your on-premises network via BGP, you must override this with a 0.0.0.0/0 UDR with the NextHopType value set as Internet to maintain direct Internet connectivity.

Azure Firewall can be configured to support forced tunneling. For more information, see Azure Firewall forced tunneling.

Note

Traffic between directly peered VNets is routed directly even if a UDR points to Azure Firewall as the default gateway. To send subnet to subnet traffic to the firewall in this scenario, a UDR must contain the target subnet network prefix explicitly on both subnets.

If you don't have an Azure subscription, create a free account before you begin.

Create the firewall hub virtual network

First, create the resource group to contain the resources for this tutorial:

  1. Sign in to the Azure portal at https://portal.azure.com.
  2. On the Azure portal home page, select Resource groups > Add.
  3. For Subscription, select your subscription.
  4. For Resource group name, type FW-Hybrid-Test.
  5. For Region, select (US) East US. All resources that you create later must be in the same location.
  6. Select Review + Create.
  7. Select Create.

Now, create the VNet:

Note

The size of the AzureFirewallSubnet subnet is /26. For more information about the subnet size, see Azure Firewall FAQ.

  1. From the Azure portal home page, select Create a resource.
  2. Under Networking, select Virtual network.
  3. Select Create.
  4. For Resource group, select FW-Hybrid-Test.
  5. For Name, type VNet-hub.
  6. Select Next: IP Addresses.
  7. For IPv4 Address space, delete the default address and type 10.5.0.0/16.
  8. Under Subnet name, select Add subnet.
  9. For Subnet name type AzureFirewallSubnet. The firewall will be in this subnet, and the subnet name must be AzureFirewallSubnet.
  10. For Subnet address range, type 10.5.0.0/26.
  11. Select Add.
  12. Select Review + create.
  13. Select Create.

Create the spoke virtual network

  1. From the Azure portal home page, select Create a resource.
  2. In Networking, select Virtual network.
  3. For Resource group, select FW-Hybrid-Test.
  4. For Name, type VNet-Spoke.
  5. For Region, select (US) East US.
  6. Select Next: IP Addresses.
  7. For IPv4 address space, delete the default address and type 10.6.0.0/16.
  8. Under Subnet name, select Add subnet.
  9. For Subnet name type SN-Workload.
  10. For Subnet address range, type 10.6.0.0/24.
  11. Select Add.
  12. Select Review + create.
  13. Select Create.

Create the on-premises virtual network

  1. From the Azure portal home page, select Create a resource.
  2. In Networking, select Virtual network.
  3. For Resource group, select FW-Hybrid-Test.
  4. For Name, type VNet-OnPrem.
  5. For Region, select (US) East US.
  6. Select Next : IP Addresses
  7. For IPv4 address space, delete the default address and type 192.168.0.0/16.
  8. Under Subnet name, select Add subnet.
  9. For Subnet name type SN-Corp.
  10. For Subnet address range, type 192.168.1.0/24.
  11. Select Add.
  12. Select Review + create.
  13. Select Create.

Now create a second subnet for the gateway.

  1. On the VNet-Onprem page, select Subnets.
  2. Select +Subnet.
  3. For Name, type GatewaySubnet.
  4. For Subnet address range type 192.168.2.0/24.
  5. Select OK.

Configure and deploy the firewall

Now deploy the firewall into the firewall hub virtual network.

  1. From the Azure portal home page, select Create a resource.

  2. In the left column, select Networking, and search for and then select Firewall.

  3. On the Create a Firewall page, use the following table to configure the firewall:

    Setting Value
    Subscription <your subscription>
    Resource group FW-Hybrid-Test
    Name AzFW01
    Region East US
    Choose a virtual network Use existing:
    VNet-hub
    Public IP address Add new:
    fw-pip.
  4. Select Review + create.

  5. Review the summary, and then select Create to create the firewall.

    This takes a few minutes to deploy.

  6. After deployment completes, go to the FW-Hybrid-Test resource group, and select the AzFW01 firewall.

  7. Note the private IP address. You'll use it later when you create the default route.

Configure network rules

First, add a network rule to allow web traffic.

  1. On the AzFW01 page, Select Rules.
  2. Select the Network rule collection tab.
  3. Select Add network rule collection.
  4. For Name, type RCNet01.
  5. For Priority, type 100.
  6. For Action, select Allow.
  7. Under Rules, for Name, type AllowWeb.
  8. For Protocol, select TCP.
  9. For Source type, select IP address.
  10. For Source, type 192.168.1.0/24.
  11. For Destination type, select IP address.
  12. For Destination address, type 10.6.0.0/16
  13. For Destination Ports, type 80.

Now add a rule to allow RDP traffic.

On the second rule row, type the following information:

  1. Name, type AllowRDP.
  2. For Protocol, select TCP.
  3. For Source type, select IP address.
  4. For Source, type 192.168.1.0/24.
  5. For Destination type, select IP address.
  6. For Destination address, type 10.6.0.0/16
  7. For Destination Ports, type 3389.
  8. Select Add.

Create and connect the VPN gateways

The hub and on-premises virtual networks are connected via VPN gateways.

Create a VPN gateway for the hub virtual network

Now create the VPN gateway for the hub virtual network. Network-to-network configurations require a RouteBased VpnType. Creating a VPN gateway can often take 45 minutes or more, depending on the selected VPN gateway SKU.

  1. From the Azure portal home page, select Create a resource.
  2. In the search text box, type virtual network gateway.
  3. Select Virtual network gateway, and select Create.
  4. For Name, type GW-hub.
  5. For Region, select the same region that you used previously.
  6. For Gateway type, select VPN.
  7. For VPN type, select Route-based.
  8. For SKU, select Basic.
  9. For Virtual network, select VNet-hub.
  10. For Public IP address, select Create new, and type VNet-hub-GW-pip for the name.
  11. Accept the remaining defaults and then select Review + create.
  12. Review the configuration, then select Create.

Create a VPN gateway for the on-premises virtual network

Now create the VPN gateway for the on-premises virtual network. Network-to-network configurations require a RouteBased VpnType. Creating a VPN gateway can often take 45 minutes or more, depending on the selected VPN gateway SKU.

  1. From the Azure portal home page, select Create a resource.
  2. In the search text box, type virtual network gateway and press Enter.
  3. Select Virtual network gateway, and select Create.
  4. For Name, type GW-Onprem.
  5. For Region, select the same region that you used previously.
  6. For Gateway type, select VPN.
  7. For VPN type, select Route-based.
  8. For SKU, select Basic.
  9. For Virtual network, select VNet-Onprem.
  10. For Public IP address, select Create new, and type VNet-Onprem-GW-pip for the name.
  11. Accept the remaining defaults and then select Review + create.
  12. Review the configuration, then select Create.

Create the VPN connections

Now you can create the VPN connections between the hub and on-premises gateways.

In this step, you create the connection from the hub virtual network to the on-premises virtual network. You'll see a shared key referenced in the examples. You can use your own values for the shared key. The important thing is that the shared key must match for both connections. Creating a connection can take a short while to complete.

  1. Open the FW-Hybrid-Test resource group and select the GW-hub gateway.
  2. Select Connections in the left column.
  3. Select Add.
  4. The the connection name, type Hub-to-Onprem.
  5. Select VNet-to-VNet for Connection type.
  6. For the Second virtual network gateway, select GW-Onprem.
  7. For Shared key (PSK), type AzureA1b2C3.
  8. Select OK.

Create the on-premises to hub virtual network connection. This step is similar to the previous one, except you create the connection from VNet-Onprem to VNet-hub. Make sure the shared keys match. The connection will be established after a few minutes.

  1. Open the FW-Hybrid-Test resource group and select the GW-Onprem gateway.
  2. Select Connections in the left column.
  3. Select Add.
  4. For the connection name, type Onprem-to-Hub.
  5. Select VNet-to-VNet for Connection type.
  6. For the Second virtual network gateway, select GW-hub.
  7. For Shared key (PSK), type AzureA1b2C3.
  8. Select OK.

Verify the connection

After about five minutes or so, the status of both connections should be Connected.

Gateway connections

Peer the hub and spoke virtual networks

Now peer the hub and spoke virtual networks.

  1. Open the FW-Hybrid-Test resource group and select the VNet-hub virtual network.

  2. In the left column, select Peerings.

  3. Select Add.

  4. Under This virtual network:

    Setting name Value
    Peering link name HubtoSpoke
    Traffic to remote virtual network Allow (default)
    Traffic forwarded from remote virtual network Allow (default)
    Virtual network gateway Use this virtual network's gateway
  5. Under Remote virtual network:

    Setting name Value
    Peering link name SpoketoHub
    Virtual network deployment model Resource manager
    Subscription <your subscription>
    Virtual network VNet-Spoke
    Traffic to remote virtual network Allow (default)
    Traffic forwarded from remote virtual network Allow (default)
    Virtual network gateway Use the remote virtual network's gateway
  6. Select Add.

    Vnet peering

Create the routes

Next, create a couple routes:

  • A route from the hub gateway subnet to the spoke subnet through the firewall IP address
  • A default route from the spoke subnet through the firewall IP address
  1. From the Azure portal home page, select Create a resource.
  2. In the search text box, type route table and press Enter.
  3. Select Route table.
  4. Select Create.
  5. Select the FW-Hybrid-Test for the resource group.
  6. For Region, select the same location that you used previously.
  7. For the name, type UDR-Hub-Spoke.
  8. Select Review + Create.
  9. Select Create.
  10. After the route table is created, select it to open the route table page.
  11. Select Routes in the left column.
  12. Select Add.
  13. For the route name, type ToSpoke.
  14. For the address prefix, type 10.6.0.0/16.
  15. For next hop type, select Virtual appliance.
  16. For next hop address, type the firewall's private IP address that you noted earlier.
  17. Select OK.

Now associate the route to the subnet.

  1. On the UDR-Hub-Spoke - Routes page, select Subnets.
  2. Select Associate.
  3. Under Virtual network, select VNet-hub.
  4. Under Subnet, select GatewaySubnet.
  5. Select OK.

Now create the default route from the spoke subnet.

  1. From the Azure portal home page, select Create a resource.
  2. In the search text box, type route table and press Enter.
  3. Select Route table.
  4. Select Create.
  5. Select the FW-Hybrid-Test for the resource group.
  6. For Region, select the same location that you used previously.
  7. For the name, type UDR-DG.
  8. For Propagate gateway route, select No.
  9. Select Review + Create.
  10. Select Create.
  11. After the route table is created, select it to open the route table page.
  12. Select Routes in the left column.
  13. Select Add.
  14. For the route name, type ToHub.
  15. For the address prefix, type 0.0.0.0/0.
  16. For next hop type, select Virtual appliance.
  17. For next hop address, type the firewall's private IP address that you noted earlier.
  18. Select OK.

Now associate the route to the subnet.

  1. On the UDR-DG - Routes page, select Subnets.
  2. Select Associate.
  3. Under Virtual network, select VNet-spoke.
  4. Under Subnet, select SN-Workload.
  5. Select OK.

Create virtual machines

Now create the spoke workload and on-premises virtual machines, and place them in the appropriate subnets.

Create the workload virtual machine

Create a virtual machine in the spoke virtual network, running IIS, with no public IP address.

  1. From the Azure portal home page, select Create a resource.
  2. Under Popular, select Windows Server 2016 Datacenter.
  3. Enter these values for the virtual machine:
    • Resource group - Select FW-Hybrid-Test.
    • Virtual machine name: VM-Spoke-01.
    • Region - Same region that you're used previously.
    • User name: <type a user name>.
    • Password: <type a password>
  4. For Public inbound ports, select Allow selected ports, and then select HTTP (80), and RDP (3389)
  5. Select Next:Disks.
  6. Accept the defaults and select Next: Networking.
  7. Select VNet-Spoke for the virtual network and the subnet is SN-Workload.
  8. For Public IP, select None.
  9. Select Next:Management.
  10. For Boot diagnostics, Select Disable.
  11. Select Review+Create, review the settings on the summary page, and then select Create.

Install IIS

  1. From the Azure portal, open the Cloud Shell and make sure that it's set to PowerShell.

  2. Run the following command to install IIS on the virtual machine and change the location if necessary:

    Set-AzVMExtension `
            -ResourceGroupName FW-Hybrid-Test `
            -ExtensionName IIS `
            -VMName VM-Spoke-01 `
            -Publisher Microsoft.Compute `
            -ExtensionType CustomScriptExtension `
            -TypeHandlerVersion 1.4 `
            -SettingString '{"commandToExecute":"powershell Add-WindowsFeature Web-Server; powershell      Add-Content -Path \"C:\\inetpub\\wwwroot\\Default.htm\" -Value $($env:computername)"}' `
            -Location EastUS
    

Create the on-premises virtual machine

This is a virtual machine that you use to connect using Remote Desktop to the public IP address. From there, you then connect to the on-premises server through the firewall.

  1. From the Azure portal home page, select Create a resource.
  2. Under Popular, select Windows Server 2016 Datacenter.
  3. Enter these values for the virtual machine:
    • Resource group - Select existing, and then select FW-Hybrid-Test.
    • Virtual machine name - VM-Onprem.
    • Region - Same region that you're used previously.
    • User name: <type a user name>.
    • Password: <type a user password>.
  4. For Public inbound ports, select Allow selected ports, and then select RDP (3389)
  5. Select Next:Disks.
  6. Accept the defaults and select Next:Networking.
  7. Select VNet-Onprem for virtual network and the subnet is SN-Corp.
  8. Select Next:Management.
  9. For Boot diagnostics, Select Disable.
  10. Select Review+Create, review the settings on the summary page, and then select Create.

Test the firewall

  1. First, note the private IP address for VM-spoke-01 virtual machine.

  2. From the Azure portal, connect to the VM-Onprem virtual machine.

  1. Open a web browser on VM-Onprem, and browse to http://<VM-spoke-01 private IP>.

    You should see the VM-spoke-01 web page: VM-Spoke-01 web page

  2. From the VM-Onprem virtual machine, open a remote desktop to VM-spoke-01 at the private IP address.

    Your connection should succeed, and you should be able to sign in.

So now you've verified that the firewall rules are working:

  • You can browse web server on the spoke virtual network.
  • You can connect to the server on the spoke virtual network using RDP.

Next, change the firewall network rule collection action to Deny to verify that the firewall rules work as expected.

  1. Select the AzFW01 firewall.
  2. Select Rules.
  3. Select the Network rule collection tab and select the RCNet01 rule collection.
  4. For Action, select Deny.
  5. Select Save.

Close any existing remote desktops before testing the changed rules. Now run the tests again. They should all fail this time.

Clean up resources

You can keep your firewall resources for the next tutorial, or if no longer needed, delete the FW-Hybrid-Test resource group to delete all firewall-related resources.

Next steps

Next, you can monitor the Azure Firewall logs.