About Cloudflare Firewall Rules

Cloudflare Firewall Rules is a flexible and intuitive framework for filtering HTTP requests. It gives you fine-grained control over which requests reach your applications, proactively inspecting incoming site traffic and automatically responding to threats.

In a firewall rule you define an expression that tells Cloudflare what to look for in a request, and specify the appropriate action to take when those conditions are met. Expressions can reference IP lists - groups of IP addresses that you can reference collectively by name.

To write firewall rule expressions, use the Rules language, a powerful expression language inspired in the Wireshark Display Filter language.