Palo Alto Site to Site VPN Configuration (with Azure)

Introduction

This tutorial guides you through configuring a Site-to-Site VPN between a Palo Alto firewall and Microsoft Azure. By following the steps outlined, you will establish a secure connection that allows for seamless communication between your on-premises network and Azure resources.

Step 1: Understand the Network Diagram

• Familiarize yourself with the network architecture that includes:
  • On-premises network (Palo Alto firewall)
  • Azure virtual network
  • VPN Gateway in Azure
• This foundational knowledge is crucial for configuring the VPN correctly.

Step 2: Prepare for VPN Configuration

• Identify the tasks needed for the VPN setup:
  • Configure the tunnel interface on the Palo Alto firewall.
  • Set up the IKE gateway.
  • Establish the IPSec tunnel.
  • Configure routing for traffic.
• Gather necessary information:
  • Public IP address of the Azure VPN Gateway.
  • Shared secret for authentication.

Step 3: Configure the Tunnel Interface

• Access the Palo Alto firewall management console.
• Navigate to Network > Interfaces.
• Create a new tunnel interface:
  • Select Add.
  • Choose a name (e.g., "tunnel.1").
  • Set the virtual router and security zone (e.g., "VPN").
• Assign the interface an IP address that fits within your network.

Step 4: Set Up the IKE Gateway

• Go to Network > IKE Gateways.
• Click Add to create a new IKE gateway:
  • Name the gateway (e.g., "IKE-Gateway").
  • Set the interface to the tunnel you created.
  • Input the Azure VPN Gateway public IP address.
  • Choose the appropriate IKE version (usually IKEv2).
  • Enter the pre-shared key you gathered earlier.
• Specify the IKE phase 1 settings (encryption, authentication, etc.) according to your security requirements.

Step 5: Establish the IPSec Tunnel

• Navigate to Network > IPSec Tunnels and click Add.
• Configure the tunnel settings:
  • Name the tunnel (e.g., "IPSec-Tunnel").
  • Set the Tunnel Interface to the tunnel you created.
  • Link it to the IKE Gateway you configured.
• Define the IPSec settings:
  • Select encryption and authentication protocols.
  • Specify the local and remote subnets that will communicate through the tunnel.

Step 6: Configure Routing

• Go to Network > Virtual Routers.
• Select the virtual router that contains your tunnel interface.
• Add a route to the Azure subnet:
  • Destination: Azure virtual network address range.
  • Next hop: Tunnel interface.
• Ensure that the route is active.

Step 7: Verify Tunnel Status

• Check the status of the VPN tunnel on the Palo Alto firewall:
  • Navigate to Network > IPSec Tunnels.
  • Ensure the tunnel shows as "up."
• Log in to the Azure portal:
  • Navigate to Virtual Network Gateway.
  • Confirm that the connection status is established.

Conclusion

You have successfully configured a Site-to-Site VPN between a Palo Alto firewall and Microsoft Azure. Key steps included setting up the tunnel interface, IKE gateway, IPSec tunnel, and routing. To ensure ongoing connectivity, regularly monitor the tunnel status and review configurations for updates or changes. Consider exploring additional configurations for enhanced security and performance.