CDN in AEM as a Cloud Service cdn

AEM as Cloud Service is shipped with a built-in CDN. Its main purpose is to reduce latency by delivering cacheable content from the CDN nodes at the edge, near the browser. It is fully managed and configured for optimal performance of AEM applications.

The AEM-managed CDN satisfies most customer’s performance and security requirements. For the publish tier, customers can optionally point to it from their own CDN, which they must manage. This scenario is allowed on a case-by-case basis, based on meeting certain pre-requisites including, but not limited to, the customer having a legacy integration with their CDN vendor that is difficult to abandon.

AEM-managed CDN aem-managed-cdn

Follow the sections below to use Cloud Manager self-service UI to prepare for content delivery by using AEM’s out-of-the-box CDN:

Restricting traffic

By default, for an AEM-managed CDN setup, all public traffic can make its way to the publish service, for both production and non-production (development and stage) environments. You can limit traffic to the publish service for a given environment (for example, limiting staging by a range of IP addresses) by way of the Cloud Manager user interface.

See Managing IP Allow Lists to learn more.

Only requests from the allowed IPs are served by AEM’s managed CDN. If you point your own CDN to the AEM-managed CDN, then make sure the IPs of your CDN are included in the allowlist.

Configuring Traffic at the CDN cdn-configuring-cloud

Rules to configure CDN traffic and filters can be declared in a configuration file and deployed to the CDN, by using the Cloud Manager’s Configuration Pipeline. For more details, see Configuring Traffic at the CDN and Traffic Filter rules including WAF rules.

Configuring CDN Error Pages cdn-error-pages

A CDN error page can be configured to override the default, unbranded page that is served to the browser in the rare event that AEM cannot be reached. For more details, see Configuring CDN error pages.

Customer CDN points to AEM-managed CDN point-to-point-CDN

If a customer must use its existing CDN, they may manage it and point it to the AEM-managed CDN, providing the following are satisfied:

  • Customer must have an existing CDN that would be onerous to replace.
  • Customer must manage it.
  • Customer must be able to configure the CDN to work with AEM as a Cloud Service - see the configuration instructions presented below.
  • Customer must have engineering CDN experts that are on call in case-related issues arise.
  • Customer must perform and successfully pass a load test before going to production.

Configuration instructions:

  1. Point your CDN to the Adobe CDN’s ingress as its origin domain. For example, publish-p<PROGRAM_ID>-e<ENV-ID>

  2. Set SNI to the Adobe CDN’s ingress.

  3. Set the Host header to the origin domain. For example: Host:publish-p<PROGRAM_ID>-e<ENV-ID>

  4. Set the X-Forwarded-Host header with the domain name so AEM can determine the host header. For example:

  5. Set X-AEM-Edge-Key. The value should come from Adobe.

    • Needed so that the Adobe CDN can validate the source of the requests and pass the X-Forwarded-* headers to the AEM application. For example,X-Forwarded-For is used to determine the client IP. So, it becomes the responsibility of the trusted caller (that is, the customer-managed CDN) to ensure the correctness of the X-Forwarded-* headers (see the note below).
    • Optionally, access to Adobe CDN’s ingress can be blocked when an X-AEM-Edge-Key is not present. Inform Adobe if you need direct access to Adobe CDN’s ingress (to be blocked).

See the Sample CDN vendor configurations section for configuration examples from leading CDN vendors.

Before accepting live traffic, you should validate with Adobe’s customer support that the end-to-end traffic routing is functioning correctly.

After obtaining the X-AEM-Edge-Key, you can test that the request is routed correctly as follows.

In Linux®:

curl https://publish-p<PROGRAM_ID>-e<ENV-ID> -H "X-Forwarded-Host:" -H "X-AEM-Edge-Key: <PROVIDED_EDGE_KEY>"

In Windows:

curl https://publish-p<PROGRAM_ID>-e<ENV-ID> --header "X-Forwarded-Host:" --header "X-AEM-Edge-Key: <PROVIDED_EDGE_KEY>"
When using your own CDN, you do not need to install domains and certificates in Cloud Manager. The routing in the Adobe CDN is done by using the default domain publish-p<PROGRAM_ID>-e<ENV-ID> which should be sent in the request Host header. Overwriting the request Host header with a custom domain name can cause the request to be incorrectly routed by the Adobe CDN.
Customers that manage their own CDN should ensure the integrity of the headers that are sent through to AEM’s CDN. For instance, it is recommended that customers clear all X-Forwarded-* headers and set them to known and controlled values. For example, X-Forwarded-For should contain the client’s IP address, while X-Forwarded-Host should contain the site’s host.
Sandbox program environments do not support a customer-provided CDN.

The extra hop between the customer CDN and the AEM CDN is only needed if there is a cache miss. By using the cache optimization strategies described in this article, the addition of a customer CDN should only introduce negligible latency.

This customer CDN configuration is supported for the publish tier, but not in front of the author tier.

Sample CDN vendor configurations sample-configurations

Presented below are several configuration examples from several leading CDN vendors.


Akamai1 Akamai2

Amazon CloudFront

CloudFront1 CloudFront2


Cloudflare1 Cloudflare2

Geolocation Headers geo-headers

The AEM-managed CDN adds headers to each request with:

  • country code: x-aem-client-country
  • continent code: x-aem-client-continent
If there is a customer-managed CDN, these headers reflect the location of the customers CDN proxy server rather than the actual client. Therefore, for customer-managed CDN, geolocation headers should be managed by the customers CDN.

The values for the country codes are the Alpha-2 codes described here.

The values for the continent codes are:

  • AF Africa
  • AN Antarctica
  • AS Asia
  • EU Europe
  • NA North America
  • OC Oceania
  • SA South America

This information may be useful for use cases such as redirecting to a different url based on the origin (country) of the request. Use the Vary header for caching responses that depend on geo information. For example, redirects to a specific country landing page should always contain Vary: x-aem-client-country. If needed, you can use Cache-Control: private to prevent caching. See also Caching.