Setting up an IPSec tunnel between a FortiGate firewall and Microsoft Azure can seem daunting, but don't worry, guys! I'm here to guide you through the process. This connection allows you to securely connect your on-premises network to your Azure virtual network, creating a hybrid cloud environment. This article provides a comprehensive guide to configuring an IPSec tunnel between a FortiGate firewall and Microsoft Azure. An IPSec tunnel provides a secure communication channel between your on-premises network and your Azure virtual network, which is essential for many hybrid cloud scenarios. Before diving into the configuration, it's crucial to understand the components involved and plan your network accordingly. This includes defining the IP address ranges for your on-premises network and your Azure virtual network, as well as choosing the appropriate security parameters for the IPSec tunnel. Make sure that the IP address ranges do not overlap to avoid routing conflicts. Also, consider the performance requirements of your applications when selecting encryption algorithms and key exchange methods. The stronger the encryption, the more secure the tunnel, but it may also impact performance. Thorough planning will save you time and effort in the long run and ensure a stable and secure connection between your FortiGate firewall and Azure. Remember to document your configurations for future reference and troubleshooting. This will help you quickly identify and resolve any issues that may arise. Regular monitoring of the IPSec tunnel is also recommended to ensure its continued health and performance. By following these guidelines, you can successfully establish a secure and reliable IPSec tunnel between your FortiGate firewall and Azure. This will enable you to seamlessly extend your on-premises network to the cloud and take advantage of the many benefits that Azure has to offer. So, let's get started and unlock the power of hybrid cloud computing!

Prerequisites

Before we get started, let's make sure you have everything you need:

• An active Microsoft Azure subscription.
• A FortiGate firewall with internet access.
• An Azure Virtual Network (VNet) already set up.
• A Virtual Network Gateway in Azure configured for VPN.
• Static public IP addresses for both your FortiGate and Azure VPN Gateway.

Make sure your FortiGate is running a firmware version that supports the features required for the Azure VPN Gateway configuration. It's always a good idea to keep your firmware up to date to benefit from the latest security patches and features. Verify that your Azure Virtual Network (VNet) has a valid address space and that your subnets are properly configured. The address space should not overlap with your on-premises network to avoid routing issues. Your Virtual Network Gateway should be configured with a public IP address and a gateway subnet. The gateway subnet is a dedicated subnet for the VPN gateway and should not contain any other resources. Also, ensure that your FortiGate firewall has a static public IP address assigned to its WAN interface. This IP address will be used to establish the IPSec tunnel with the Azure VPN Gateway. Having these prerequisites in place will ensure a smooth and successful configuration process.

Step-by-Step Configuration

Alright, let's dive into the configuration steps:

1. Create a Virtual Network Gateway in Azure

If you haven't already, create a Virtual Network Gateway in your Azure VNet. When creating the gateway, select the "VPN" gateway type and choose a suitable SKU based on your bandwidth requirements. The Virtual Network Gateway serves as the endpoint for the IPSec tunnel in Azure. When creating the gateway, you'll need to choose a gateway type, which should be "VPN" for this scenario. You'll also need to select a SKU, which determines the performance and cost of the gateway. Choose a SKU that meets your bandwidth requirements and budget. The gateway creation process can take some time, so be patient. Once the gateway is created, you'll need to configure it with the appropriate settings for the IPSec tunnel. This includes specifying the IPSec policy, the shared key, and the IP address of your FortiGate firewall. You can configure these settings using the Azure portal, PowerShell, or the Azure CLI. Make sure to document your configuration settings for future reference and troubleshooting. Regular monitoring of the Virtual Network Gateway is also recommended to ensure its continued health and performance. By following these steps, you can successfully create and configure a Virtual Network Gateway in Azure for your IPSec tunnel with FortiGate.

2. Configure the FortiGate Firewall

Log into your FortiGate firewall's web interface and follow these steps:

• Create a new VPN Tunnel: Go to VPN > IPSec Wizard and start a new tunnel.
• Tunnel Settings:
  • Set the Template type to Custom.
  • Enter a Name for the tunnel (e.g., "Azure-VPN").
  • Set IP Version to IPv4.
  • For the Remote Gateway, select Static IP Address and enter the public IP address of your Azure VPN Gateway.
  • Set the Interface to the FortiGate interface that connects to the internet (usually wan1).
• Authentication:
  • Set Authentication Method to Pre-shared Key.
  • Enter a strong Pre-shared Key. Make sure to use the same key on both the FortiGate and Azure.
• IPSec Policy:
  • Enable Phase 1 Proposal and Phase 2 Proposal.
  • Configure the following settings:
    • Phase 1:
      • Encryption: AES256
      • Authentication: SHA256
      • DH Group: 14 (2048 bit)
      • Key Lifetime: 28800 seconds
    • Phase 2:
      • Encryption: AES256
      • Authentication: SHA256
      • Perfect Forward Secrecy (PFS): Enable and set DH Group to 14 (2048 bit)
      • Key Lifetime: 3600 seconds
• Local and Remote Networks:
  • Specify the local network behind the FortiGate (your on-premises network) and the remote network in Azure (your VNet address space).
• Create Static Routes: Add static routes on the FortiGate to direct traffic destined for the Azure VNet through the IPSec tunnel interface.

Configuring the FortiGate firewall involves several important steps to ensure a secure and reliable IPSec tunnel. First, you'll need to create a new VPN tunnel using the IPSec Wizard. This wizard will guide you through the process of configuring the tunnel settings, authentication, and IPSec policy. When setting the Template type, choose Custom to have more control over the configuration. Give the tunnel a descriptive Name to easily identify it. The IP Version should be set to IPv4 for compatibility with Azure. For the Remote Gateway, select Static IP Address and enter the public IP address of your Azure VPN Gateway. This is the IP address that the FortiGate will use to connect to the Azure VPN Gateway. The Interface should be set to the FortiGate interface that connects to the internet, typically wan1. Next, you'll need to configure the authentication settings. Set the Authentication Method to Pre-shared Key and enter a strong Pre-shared Key. This key will be used to authenticate the FortiGate with the Azure VPN Gateway. Make sure to use the same key on both sides. After configuring the authentication settings, you'll need to configure the IPSec Policy. This involves enabling Phase 1 Proposal and Phase 2 Proposal. In Phase 1, set the Encryption to AES256, the Authentication to SHA256, the DH Group to 14 (2048 bit), and the Key Lifetime to 28800 seconds. In Phase 2, set the Encryption to AES256, the Authentication to SHA256, enable Perfect Forward Secrecy (PFS), and set the DH Group to 14 (2048 bit) and the Key Lifetime to 3600 seconds. Finally, you'll need to specify the local and remote networks. The local network is the network behind the FortiGate (your on-premises network), and the remote network is the network in Azure (your VNet address space). You'll also need to create static routes on the FortiGate to direct traffic destined for the Azure VNet through the IPSec tunnel interface. By following these steps carefully, you can successfully configure the FortiGate firewall for an IPSec tunnel with Azure. Remember to save your configuration and test the connection to ensure that it is working properly.

3. Configure Azure VPN Gateway

In the Azure portal, navigate to your Virtual Network Gateway and configure the following:

• Connection: Create a new Connection.
• Connection Type: Select Site-to-site (IPSec).
• Virtual Network Gateway: Select your existing Virtual Network Gateway.
• Local Network Gateway: If you don't have one already, create a Local Network Gateway representing your on-premises network (i.e., your FortiGate's public IP address and the address space of your on-premises network).
• Shared Key (PSK): Enter the same Pre-shared Key you configured on the FortiGate.
• IPSec/IKE policy:
  • Enable custom policy and configure the following:
    • IKE Phase 1:
      • Encryption: AES256
      • Integrity: SHA256
      • DH Group: DHGroup14
    • IKE Phase 2:
      • Encryption: AES256
      • Integrity: SHA256
      • PFS Group: PFS14
• SA lifetime (seconds): 3600
• Traffic selector:
  • Configure the traffic selector to match the local and remote networks defined on the FortiGate.

Configuring the Azure VPN Gateway involves setting up a connection to your FortiGate firewall and defining the IPSec policy. First, you'll need to create a new Connection in the Azure portal. Choose Site-to-site (IPSec) as the Connection Type. Select your existing Virtual Network Gateway. If you don't already have a Local Network Gateway, you'll need to create one. The Local Network Gateway represents your on-premises network and includes the public IP address of your FortiGate and the address space of your on-premises network. Enter the same Pre-shared Key that you configured on the FortiGate. This key is used to authenticate the connection between Azure and your FortiGate. Next, you'll need to configure the IPSec/IKE policy. Enable custom policy and configure the following settings for IKE Phase 1: set the Encryption to AES256, the Integrity to SHA256, and the DH Group to DHGroup14. For IKE Phase 2, set the Encryption to AES256, the Integrity to SHA256, and the PFS Group to PFS14. Set the SA lifetime (seconds) to 3600. Finally, you'll need to configure the traffic selector to match the local and remote networks defined on the FortiGate. This ensures that only traffic destined for the Azure VNet is routed through the IPSec tunnel. By carefully configuring these settings, you can establish a secure and reliable connection between your Azure VPN Gateway and your FortiGate firewall. Remember to save your configuration and test the connection to ensure that it is working properly. Regular monitoring of the connection is also recommended to ensure its continued health and performance.

4. Verify the Tunnel

After completing the configurations, verify the tunnel status on both the FortiGate and Azure portals. On the FortiGate, go to VPN > Monitor > IPSec Monitor to see if the tunnel is up. In Azure, check the Connection status in the Virtual Network Gateway overview. To verify the tunnel, you can check the IPSec Monitor on the FortiGate to see if the tunnel is up and running. Also, you can examine the logs on both the FortiGate and Azure to identify any issues.

Troubleshooting Tips

Having issues? Here are a few things to check:

• Pre-shared Keys: Ensure the Pre-shared Keys match on both sides. Even a small typo can prevent the tunnel from establishing.
• IPSec Policies: Double-check that the IPSec policies (encryption, authentication, DH groups) are identical on both the FortiGate and Azure.
• Firewall Rules: Make sure that the necessary firewall rules are in place to allow traffic to pass through the tunnel. On the FortiGate, ensure that you have firewall policies allowing traffic between your on-premises network and the Azure VNet. In Azure, verify that your network security groups (NSGs) allow traffic from your on-premises network to your Azure resources.
• Routing: Verify that the routing is configured correctly on both the FortiGate and Azure. Traffic destined for the remote network should be routed through the IPSec tunnel.

Conclusion

That's it, guys! You've successfully configured an IPSec tunnel between your FortiGate and Azure. This secure connection enables you to extend your on-premises network into Azure, unlocking a world of possibilities for hybrid cloud deployments. By following the steps outlined in this article, you can establish a secure and reliable connection between your FortiGate firewall and Microsoft Azure. This will enable you to seamlessly integrate your on-premises network with your Azure virtual network, creating a hybrid cloud environment. Remember to carefully plan your network configuration, including IP address ranges and security parameters, before starting the configuration process. Also, be sure to document your configurations for future reference and troubleshooting. Regular monitoring of the IPSec tunnel is also recommended to ensure its continued health and performance. With a properly configured IPSec tunnel, you can securely access your Azure resources from your on-premises network and vice versa. This opens up a wide range of possibilities for hybrid cloud deployments, such as running applications across both environments, backing up data to Azure, and extending your network to the cloud. So, go ahead and take advantage of the power of hybrid cloud computing with your FortiGate and Azure!