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Concepts

The Cloudflare Web Application Firewall (Cloudflare WAF) checks incoming web requests and filters undesired traffic based on sets of rules called rulesets. The matching engine that powers the WAF rules supports the wirefilter syntax using the Rules language.


​​ Managed Rulesets

The Cloudflare WAF includes several Managed Rulesets, provided by Cloudflare, that you can enable and configure.

When you enable these Managed Rulesets, you get immediate protection from a broad set of security rules that are regularly updated. Each of these rules has a default action that varies according to the severity of the rule.

You can override the default action or disable one or more rules included in Managed Rulesets. To customize the rules behavior you define specific configurations or overrides.

You can define a configuration that affects an entire Managed Ruleset, or configure the action and status of one or more rules in the ruleset. Rules have associated tags that allow you to search for a specific group of rules and configure them in bulk.

​​ Rule execution order

Cloudflare evaluates different types of rules when processing incoming requests. The rule execution order is the following:

  1. Firewall rules
  2. Custom rulesets
  3. Custom rules
  4. Rate limiting rules
  5. WAF Managed Rulesets
  6. Cloudflare Rate Limiting (previous version)

For more information on the Ruleset Engine phases where each WAF feature will execute, refer to WAF phases.