AWS::WAFv2::RuleGroup RateBasedStatement

A rate-based rule counts incoming requests and rate limits requests when they are coming at too fast a rate. The rule categorizes requests according to your aggregation criteria, collects them into aggregation instances, and counts and rate limits the requests for each instance.

You can specify individual aggregation keys, like IP address or HTTP method. You can also specify aggregation key combinations, like IP address and HTTP method, or HTTP method, query argument, and cookie.

Each unique set of values for the aggregation keys that you specify is a separate aggregation instance, with the value from each key contributing to the aggregation instance definition.

For example, assume the rule evaluates web requests with the following IP address and HTTP method values:

The rule would create different aggregation instances according to your aggregation criteria, for example:

For any n-tuple of aggregation keys, each unique combination of values for the keys defines a separate aggregation instance, which AWS WAF counts and rate-limits individually.

You can optionally nest another statement inside the rate-based statement, to narrow the scope of the rule so that it only counts and rate limits requests that match the nested statement. You can use this nested scope-down statement in conjunction with your aggregation key specifications or you can just count and rate limit all requests that match the scope-down statement, without additional aggregation. When you choose to just manage all requests that match a scope-down statement, the aggregation instance is singular for the rule.

You cannot nest a RateBasedStatement inside another statement, for example inside a NotStatement or OrStatement. You can define a RateBasedStatement inside a web ACL and inside a rule group.

For additional information about the options, see Rate limiting web requests using rate-based rules in the AWS WAF Developer Guide.

If you only aggregate on the individual IP address or forwarded IP address, you can retrieve the list of IP addresses that AWS WAF is currently rate limiting for a rule through the API call GetRateBasedStatementManagedKeys. This option is not available for other aggregation configurations.

AWS WAF tracks and manages web requests separately for each instance of a rate-based rule that you use. For example, if you provide the same rate-based rule settings in two web ACLs, each of the two rule statements represents a separate instance of the rate-based rule and gets its own tracking and management by AWS WAF. If you define a rate-based rule inside a rule group, and then use that rule group in multiple places, each use creates a separate instance of the rate-based rule that gets its own tracking and management by AWS WAF.

Syntax

To declare this entity in your AWS CloudFormation template, use the following syntax:

{
  "AggregateKeyType" : String,
  "CustomKeys" : [ RateBasedStatementCustomKey, ... ],
  "EvaluationWindowSec" : Integer,
  "ForwardedIPConfig" : ForwardedIPConfiguration,
  "Limit" : Integer,
  "ScopeDownStatement" : Statement
}

  AggregateKeyType: String
  CustomKeys: 
    - RateBasedStatementCustomKey
  EvaluationWindowSec: Integer
  ForwardedIPConfig: 
    ForwardedIPConfiguration
  Limit: Integer
  ScopeDownStatement: 
    Statement

Properties

See also

For examples of rate-based statements, see the AWS::WAFv2::WebACL RateBasedStatement property.