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Tutorial: Deploy a firewall with Azure DDoS Protection

  • Article

This article helps you create an Azure Firewall with a DDoS protected virtual network. Azure DDoS Protection enables enhanced DDoS mitigation capabilities such as adaptive tuning, attack alert notifications, and monitoring to protect your firewall from large scale DDoS attacks.

Important

Azure DDoS Protection incurs a cost when you use the Network Protection SKU. Overages charges only apply if more than 100 public IPs are protected in the tenant. Ensure you delete the resources in this tutorial if you aren't using the resources in the future. For information about pricing, see Azure DDoS Protection Pricing. For more information about Azure DDoS protection, see What is Azure DDoS Protection?.

For this tutorial, you create a simplified single VNet with two subnets for easy deployment. Azure DDoS Network Protection is enabled for the virtual network.

  • AzureFirewallSubnet - the firewall is in this subnet.
  • Workload-SN - the workload server is in this subnet. This subnet's network traffic goes through the firewall.

Tutorial network infrastructure

For production deployments, a hub and spoke model is recommended, where the firewall is in its own VNet. The workload servers are in peered VNets in the same region with one or more subnets.

In this tutorial, you learn how to:

  • Set up a test network environment
  • Deploy a firewall and firewall policy
  • Create a default route
  • Configure an application rule to allow access to www.google.com
  • Configure a network rule to allow access to external DNS servers
  • Configure a NAT rule to allow a remote desktop to the test server
  • Test the firewall

If you prefer, you can complete this procedure using Azure PowerShell.

Prerequisites

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

Set up the network

First, create a resource group to contain the resources needed to deploy the firewall. Then create a VNet, subnets, and a test server.

Create a resource group

The resource group contains all the resources for the tutorial.

  1. Sign in to the Azure portal.

  2. On the Azure portal menu, select Resource groups or search for and select Resource groups from any page, then select Add. Enter or select the following values:

    Setting Value
    Subscription Select your Azure subscription.
    Resource group Enter Test-FW-RG.
    Region Select a region. All other resources that you create must be in the same region.

  3. Select Review + create.

  4. Select Create.

Create a DDoS protection plan

  1. In the search box at the top of the portal, enter DDoS protection. Select DDoS protection plans in the search results and then select + Create.

  2. In the Basics tab of Create a DDoS protection plan page, enter or select the following information:

    Setting Value
    Project details
    Subscription Select your Azure subscription.
    Resource group Select Test-FW-RG.
    Instance details
    Name Enter myDDoSProtectionPlan.
    Region Select the region.

  3. Select Review + create and then select Create to deploy the DDoS protection plan.

Create a VNet

This VNet will have two subnets.

Note

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

  1. On the Azure portal menu or from the Home page, select Create a resource.

  2. Select Networking.

  3. Search for Virtual network and select it.

  4. Select Create, then enter or select the following values:

    Setting Value
    Subscription Select your Azure subscription.
    Resource group Select Test-FW-RG.
    Name Enter Test-FW-VN.
    Region Select the same location that you used previously.

  5. Select Next: IP addresses.

  6. For IPv4 Address space, accept the default 10.1.0.0/16.

  7. Under Subnet, select default.

  8. For Subnet name change the name to AzureFirewallSubnet. The firewall will be in this subnet, and the subnet name must be AzureFirewallSubnet.

  9. For Address range, type 10.1.1.0/26.

  10. Select Save.

    Next, create a subnet for the workload server.

  11. Select Add subnet.

  12. For Subnet name, type Workload-SN.

  13. For Subnet address range, type 10.1.2.0/24.

  14. Select Add.

  15. Select Next: Security.

  16. In DDoS Network Protection select Enable.

  17. Select myDDoSProtectionPlan in DDoS protection plan.

  18. Select Review + create.

  19. Select Create.

Create a virtual machine

Now create the workload virtual machine, and place it in the Workload-SN subnet.

  1. On the Azure portal menu or from the Home page, select Create a resource.

  2. Select Windows Server 2019 Datacenter.

  3. Enter or select these values for the virtual machine:

    Setting Value
    Subscription Select your Azure subscription.
    Resource group Select Test-FW-RG.
    Virtual machine name Enter Srv-Work.
    Region Select the same location that you used previously.
    Username Enter a username.
    Password Enter a password.

  4. Under Inbound port rules, Public inbound ports, select None.

  5. Accept the other defaults and select Next: Disks.

  6. Accept the disk defaults and select Next: Networking.

  7. Make sure that Test-FW-VN is selected for the virtual network and the subnet is Workload-SN.

  8. For Public IP, select None.

  9. Accept the other defaults and select Next: Management.

  10. Select Disable to disable boot diagnostics. Accept the other defaults and select Review + create.

  11. Review the settings on the summary page, and then select Create.

  12. After the deployment completes, select the Srv-Work resource and note the private IP address for later use.

Deploy the firewall and policy

Deploy the firewall into the VNet.

  1. On the Azure portal menu or from the Home page, select Create a resource.

  2. Type firewall in the search box and press Enter.

  3. Select Firewall and then select Create.

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

    Setting Value
    Subscription Select your Azure subscription.
    Resource group Select Test-FW-RG.
    Name Enter Test-FW01.
    Region Select the same location that you used previously.
    Firewall management Select Use a Firewall Policy to manage this firewall.
    Firewall policy Select Add new, and enter fw-test-pol.
    Select the same region that you used previously.
    Choose a virtual network Select Use existing, and then select Test-FW-VN.
    Public IP address Select Add new, and enter fw-pip for the Name.

  5. Accept the other default values, then select Review + create.

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

    This will take a few minutes to deploy.

  7. After deployment completes, go to the Test-FW-RG resource group, and select the Test-FW01 firewall.

  8. Note the firewall private and public IP addresses. You'll use these addresses later.

Create a default route

For the Workload-SN subnet, configure the outbound default route to go through the firewall.

  1. On the Azure portal menu, select All services or search for and select All services from any page.

  2. Under Networking, select Route tables.

  3. Select Create, then enter or select the following values:

    Setting Value
    Subscription Select your Azure subscription.
    Resource group Select Test-FW-RG.
    Region Select the same location that you used previously.
    Name Enter Firewall-route.

  4. Select Review + create.

  5. Select Create.

After deployment completes, select Go to resource.

  1. On the Firewall-route page, select Subnets and then select Associate.
  2. Select Virtual network > Test-FW-VN.
  3. For Subnet, select Workload-SN. Make sure that you select only the Workload-SN subnet for this route, otherwise your firewall won't work correctly.
  4. Select OK.
  5. Select Routes and then select Add.
  6. For Route name, enter fw-dg.
  7. For Address prefix, enter 0.0.0.0/0.
  8. For Next hop type, select Virtual appliance. Azure Firewall is actually a managed service, but virtual appliance works in this situation.
  9. For Next hop address, enter the private IP address for the firewall that you noted previously.
  10. Select OK.

Configure an application rule

This is the application rule that allows outbound access to www.google.com.

  1. Open the Test-FW-RG resource group, and select the fw-test-pol firewall policy.
  2. Select Application rules.
  3. Select Add a rule collection.
  4. For Name, enter App-Coll01.
  5. For Priority, enter 200.
  6. For Rule collection action, select Allow.
  7. Under Rules, for Name, enter Allow-Google.
  8. For Source type, select IP address.
  9. For Source, enter 10.0.2.0/24.
  10. For Protocol:port, enter http, https.
  11. For Destination Type, select FQDN.
  12. For Destination, enter www.google.com
  13. Select Add.

Azure Firewall includes a built-in rule collection for infrastructure FQDNs that are allowed by default. These FQDNs are specific for the platform and can't be used for other purposes. For more information, see Infrastructure FQDNs.

Configure a network rule

This is the network rule that allows outbound access to two IP addresses at port 53 (DNS).

  1. Select Network rules.
  2. Select Add a rule collection.
  3. For Name, enter Net-Coll01.
  4. For Priority, enter 200.
  5. For Rule collection action, select Allow.
  6. For Rule collection group, select DefaultNetworkRuleCollectionGroup.
  7. Under Rules, for Name, enter Allow-DNS.
  8. For Source type, select IP Address.
  9. For Source, enter 10.0.2.0/24.
  10. For Protocol, select UDP.
  11. For Destination Ports, enter 53.
  12. For Destination type select IP address.
  13. For Destination, enter 209.244.0.3,209.244.0.4.
    These are public DNS servers operated by CenturyLink.
  14. Select Add.

Configure a DNAT rule

This rule allows you to connect a remote desktop to the Srv-Work virtual machine through the firewall.

  1. Select the DNAT rules.
  2. Select Add a rule collection.
  3. For Name, enter rdp.
  4. For Priority, enter 200.
  5. For Rule collection group, select DefaultDnatRuleCollectionGroup.
  6. Under Rules, for Name, enter rdp-nat.
  7. For Source type, select IP address.
  8. For Source, enter *.
  9. For Protocol, select TCP.
  10. For Destination Ports, enter 3389.
  11. For Destination Type, select IP Address.
  12. For Destination, enter the firewall public IP address.
  13. For Translated address, enter the Srv-work private IP address.
  14. For Translated port, enter 3389.
  15. Select Add.

Change the primary and secondary DNS address for the Srv-Work network interface

For testing purposes in this tutorial, configure the server's primary and secondary DNS addresses. This isn't a general Azure Firewall requirement.

  1. On the Azure portal menu, select Resource groups or search for and select Resource groups from any page. Select the Test-FW-RG resource group.
  2. Select the network interface for the Srv-Work virtual machine.
  3. Under Settings, select DNS servers.
  4. Under DNS servers, select Custom.
  5. Enter 209.244.0.3 in the Add DNS server text box, and 209.244.0.4 in the next text box.
  6. Select Save.
  7. Restart the Srv-Work virtual machine.

Test the firewall

Now, test the firewall to confirm that it works as expected.

  1. Connect a remote desktop to firewall public IP address and sign in to the Srv-Work virtual machine.

  2. Open Internet Explorer and browse to https://www.google.com.

  3. Select OK > Close on the Internet Explorer security alerts.

    You should see the Google home page.

  4. Browse to https://www.microsoft.com.

    You should be blocked by the firewall.

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

  • You can browse to the one allowed FQDN, but not to any others.
  • You can resolve DNS names using the configured external DNS server.

Clean up resources

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

Next steps

Deploy and configure Azure Firewall Premium