Azure Firewall Policy Overview - MSDN Documentation

Azure Firewall Policy: A Centralized Approach to Network Security

Azure Firewall Policy is a centralized management experience that simplifies firewall rule configuration and management across your Azure environment. It allows you to manage firewall rules in a more granular and organized way, promoting consistency and reducing the risk of misconfigurations.

Key Concepts of Azure Firewall Policy

Azure Firewall Policy is built around several core components:

Firewall Policy: The primary object that holds all your security rules and network settings for one or more Azure Firewall instances. This provides a centralized management plane.
Rule Collections: Policies are composed of rule collections, which logically group similar types of rules. This improves readability and manageability.
Rule Types: Azure Firewall supports three primary types of rules:
- Network Rules: Control outbound and inbound traffic based on IP addresses, ports, and protocols.
- Application Rules: Control outbound and inbound traffic for specific FQDNs (Fully Qualified Domain Names) and application protocols (like HTTP/S).
- DNAT Rules: Used for inbound traffic, allowing you to translate network address and port to a specific internal IP address and port.
Threat Intelligence: Policies can be configured to leverage Azure Firewall's built-in threat intelligence feeds to automatically block malicious IP addresses and URLs.
NAT Settings: Configure Network Address Translation (NAT) for both inbound and outbound traffic.

Benefits of Using Firewall Policy

Adopting Azure Firewall Policy offers several significant advantages:

Centralized Management: Manage security policies for multiple firewalls from a single location, ideal for organizations with complex network architectures.
Consistency: Ensure uniform security configurations across your VNets and subscriptions, reducing security gaps.
Simplified Rule Authoring: The structured approach with rule collections makes it easier to create, update, and audit firewall rules.
Scalability: Easily scale your security posture as your infrastructure grows without a proportional increase in management overhead.
Integration: Seamlessly integrates with other Azure security services, such as Azure Security Center and Azure Sentinel.

Note: Azure Firewall Policy is the recommended approach for managing Azure Firewall rules. While Azure Firewall Classic rules are still supported, migrating to Firewall Policy is advised for new deployments and for simplifying management of existing ones.

Policy Inheritance and Hierarchy

Firewall Policies can be associated with Hub virtual networks, Spoke virtual networks, or directly with Azure Firewall instances. Policy settings can be inherited, allowing for a layered security approach. For instance, a policy associated with a Hub VNet can be inherited by connected Spoke VNets, providing a baseline security posture.

Rule Processing Order

Understanding the order in which rules are processed is crucial for effective firewall management:

Network Rule Collection Group: Network rules within a collection group are processed first.
Application Rule Collection Group: Next, application rules are evaluated.
DNAT Rule Collection Group: Finally, DNAT rules are processed for inbound traffic.

Within each rule collection group, rules are processed based on their priority, with lower numbers indicating higher priority. The first rule that matches the traffic is applied, and processing stops.

Tip: Always test your firewall rules in a non-production environment before deploying them to production to avoid unintended network disruptions.

Conclusion

Azure Firewall Policy provides a robust and centralized mechanism for defining and managing network security rules. By leveraging its structured approach, organizations can enhance their security posture, improve operational efficiency, and ensure consistent security across their Azure deployments. Explore the related articles to dive deeper into specific aspects of Azure Firewall Policy management.