Custom rules allow you to control incoming traffic by filtering requests to a zone. You can perform actions like Block or Managed Challenge on incoming requests according to rules you define.
Like other rules evaluated by Cloudflare’s Ruleset Engine, custom rules have the following basic parameters:
- An expression that specifies the criteria you are matching traffic on using the Rules language.
- An action that specifies what to perform when there is a match for the rule.
Custom rules are evaluated in order, and some actions like Block will stop the evaluation of other rules. For more details on actions and their behavior, refer to the actions reference.
To define sets of custom rules that apply to more than one zone, use custom rulesets, which require an Enterprise plan with a paid add-on.
To create custom rules using the Cloudflare dashboard, refer to Create custom rules in the dashboard.
You can also create custom rules using the Rulesets API. Refer to Create custom rules via API for more information.