What are wildcard domains?

Wildcard domains refer to the Content Delivery Network (CDN) domains that contain wildcards. You can use wildcard domains to accelerate the content delivery for all corresponding second-level domains. For example, you can add .test.com as a CDN domain. If you map *.test.com to a CNAME domain in CDN, all second-level domains of .test.com such as a.test.com support the acceleration of content delivery. However, CDN cannot accelerate the delivery of content for third-level domains such as b.a.test.com of the wildcard domain *.test.com.

Scenarios supported by wildcard domains

Alibaba Cloud CDN supports wildcard domains. You can use wildcard domains in the following scenarios:

Rules for adding wildcard domains

To add a wildcard domain, follow these rules:
  • Each CDN domain name must be less than 100 bytes in length.
  • A maximum of three levels of wildcard domain names are supported. A third-level wildcard domain contains three dots, for example, *.b.c.com.
  • Similar to common domains, network traffic generated by all second-level domains of a wildcard domain is billed. Network traffic generated by wildcard domains is recorded in resource monitoring. The system provides billing data for all second-level domains of a wildcard domain under the same CDN domain.


A log file is provided for a single wildcard domain at specified intervals. The log file contains acceleration information for all second-level domains of the wildcard domain.

If you refresh or preload content on a cache node, URLs and directories of wildcard domains are not supported. Instead, only URLs and directories of accurate domains can be refreshed or preloaded.