Azure Firewall rule limits and calculations

Overview

High Iptables rules count in Azure firewall could lead to performance issues. It is advised to keep the lines in iptables for Azure Firewall below 20K.

azure-docs/includes/firewall-limits.md at main · MicrosoftDocs/azure-docs · GitHub

• 20,000 unique source/destinations in network rules
• Unique source/destinations in network = sum of (unique source addresses * unique destination addresses for each rule)
• An IP group counts as one address, regardless of how many IP addresses it contains.
• You can track the Firewall Policy network rule count in the policy analytics under the Insights tab. As a proxy, you can also monitor your Firewall Latency Probe metrics to ensure it stays within 20 ms even during peak hours.
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