Considerations for managing body inspection in Amazon WAF - Amazon WAF, Amazon Firewall Manager, Amazon Shield Advanced, and Amazon Shield network security director
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You can now use the updated experience to access Amazon WAF functionality anywhere in the console. For more details, see Working with the updated console experience.

Considerations for managing body inspection in Amazon WAF

The body inspection size limit is the maximum request body size that Amazon WAF can inspect. When a web request body is larger than the limit, the underlying host service only forwards the contents that are within the limit to Amazon WAF for inspection.

  • For Application Load Balancer and Amazon AppSync, the limit is fixed at 8 KB (8,192 bytes).

  • For CloudFront, API Gateway, Amazon Cognito, App Runner, and Verified Access, the default limit is 16 KB (16,384 bytes), and you can increase the limit for any of the resource types by increments of 16 KB, up to 64 KB. The setting options are 16 KB, 32 KB, 48 KB, and 64 KB.

Important

Amazon WAF does not support request body inspection rules for gRPC traffic. If you enabled these rules on the protection pack (web ACL) for a CloudFront distribution or Application Load Balancer, any request that uses gRPC will ignore the request body inspection rules. All other Amazon WAF rules will still apply. For more information, see Enable Amazon WAF for distributions in the Amazon CloudFront Developer Guide.

Oversize body handling

If your web traffic includes bodies that are larger than the limit, your configured oversize handling will apply. For information about the options for oversize handling, see Oversize web request components in Amazon WAF.

Pricing considerations for increasing the limit setting

Amazon WAF charges a base rate for inspecting traffic that's within the default limit for the resource type.

For CloudFront, API Gateway, Amazon Cognito, App Runner, and Verified Access resources, if you increase the limit setting, the traffic that Amazon WAF can inspect includes body sizes up to your new limit. You're charged extra only for the inspection of requests that have body sizes larger than the default 16 KB. For more information about pricing, see Amazon WAF Pricing.

Options for modifying the body inspection size limit

You can configure the body inspection size limit for CloudFront, API Gateway, Amazon Cognito, App Runner, or Verified Access resources.

When you create or edit a protection pack (web ACL), you can modify the body inspection size limits in the resource association configuration. For the API, see the protection pack (web ACL)'s association configuration at AssociationConfig. For the console, see the configuration on the page where you specify the protection pack (web ACL)'s associated resources. For guidance on the console configuration, see Viewing web traffic metrics in Amazon WAF.