Extending and Overriding CDN Behavior

Applies To:

HTTP LargeThis platform has been optimized to cache and deliver static content (e.g., HTML, CSS, JavaScript, ISO, multimedia, and software downloads, etc.) over HTTP or HTTPS.

HTTP SmallLegacy. If you are currently serving traffic over this platform, then you may continue to do so. However, we recommend that you serve your traffic over our more robust HTTP Large platform.

ADNThe Application Delivery Network platform has been optimized to deliver dynamic content (e.g., login credentials, account information, etc.) over HTTP or HTTPS. Typically, user-specific and database-driven content are served over this platform.

Rules EngineAllows the customization of how requests are handled by our CDN service. It may be used to override the default response provided by an origin server, CDN settings, and the default edge server behavior.

Rules Engine can be used to override and/or extend the CDN configuration defined in the MCC and the response headers defined by a web server (e.g., Apache or IIS).

Web Server (Customer Origin): A web server can define response headers that will be associated with assets requested through our CDN. Rules Engine can override the values assigned to these response headers.

Additionally, a web server can define a cache policy for the requested content through certain key response headers. Rules Engine can override this cache policy with a custom cache policy for content served through the CDN.
Default CDN Response Headers: If certain key response headers have not been defined by the origin server, then a default response header value may be assigned to the response returned to the user agent and the cached version of the asset. These default response header values can also be overridden by Rules Engine.
MCC: The MCC defines how assets may be accessed through the CDN. Rules Engine may be used to customize the actions that will take place when your content is requested.

For example, a rule may prevent users from a particular country or region from requesting content from a customer origin.

Interaction with Key Features

Rules Engine will not override the configuration defined for the following features:

Token-Based Authentication
Country Filtering

The above features secure content by directory. This configuration takes precedence over instructions provided in a rule.

It is recommended to configure the above features solely within Rules Engine. This type of configuration maximizes flexibility and reduces complexity.

Sample Scenario

This example demonstrates how Rules Engine may be used to extend the behavior of Token-Based Authentication.

It assumes the following CDN configuration:

Feature	Configuration
Token-Based Authentication	Secures the following path: /marketing/secure
Rules Engine	Enables Token-Based Authentication for all files. Bypasses Token-Based Authentication for HTML files.

Based on this configuration, the CDN will secure content as indicated below.

All requests for content stored under the /marketing/secure branch will be secured by Token-Based Authentication.
All requests, with the exception noted below, will be secured by Token-Based Authentication.
Requests for HTML and HTM files that reside outside of the /marketing/secure branch will not be secured by Token-Based Authentication.

In this scenario, valid tokens are still required for assets that support HTML pages (e.g., JS, CSS, images, etc.) that are not secured by Token-Based Authentication.

Edge Server Compression

Edge server compression should only be configured through either Rules Engine's Compress File Types feature or the Compression page.

Attempting to configure edge server compression through both Rules Engine and the Compression page will create an invalid configuration that will not be applied to your account. Furthermore, no additional configuration changes will be applied to your account until this conflict is resolved.