This topic describes the limits that Alibaba Cloud CDN imposes on domain names. Before you add a domain name to Alibaba Cloud CDN, make sure that the domain name meets the requirements. This helps you prevent losses that can be caused by violations.

Item Limit
Accelerated domain name
  • Format

    A domain name must be in lowercase letters, such as example.com. Domain names that contain Chinese characters or uppercase letters are invalid.

  • Length

    A domain name cannot exceed 67 characters in length.

  • Internet Content Provider (ICP) filing

    If the accelerated region of a domain name is set to Global or Mainland China Only, you must apply for an ICP number for the domain name. We recommend that you use Alibaba Cloud ICP Filing System to apply for ICP numbers.

  • Wildcard domain name

    Alibaba Cloud CDN supports wildcard domain names. For more information about limits on wildcard domain names, see Can I add wildcard domain names to Alibaba Cloud CDN?.

  • Domain name reclaiming

    If your domain name remains disabled for 120 days, Alibaba Cloud CDN automatically deletes configuration records that are related to the domain name. This rule also applies to domain names that fail ownership verification. If you want to continue using the domain name, you can log on to the Alibaba Cloud CDN console to add the domain name to Alibaba Cloud CDN again.

  • Domain name disabling

    For more information, see Rules for disabling accelerated domain names.

Origin server
  • The address of an origin server cannot exceed 67 characters in length.
  • You can set at most 20 origin server addresses for each accelerated domain name.
Service quota
  • Accelerated domain name

    Each Alibaba Cloud account can add at most 50 domain names to Alibaba Cloud CDN. If the average daily peak bandwidth value exceeds 50 Mbit/s and your workloads are under protection, you can submit a ticket to add more domain names to Alibaba Cloud CDN.

  • Cache refresh
    • URL refresh: 2,000 URLs per day for each Alibaba Cloud account.
    • Directory refresh: 100 directories per day for each Alibaba Cloud account.

    If your workloads within your Alibaba Cloud account require a daily bandwidth limit greater than 200 Mbit/s, you can submit a ticket to increase the quota. Alibaba Cloud will review your application and then increase the quota properly.

  • File prefetch

    You can prefetch files by using only URLs. Each Alibaba Cloud account can submit at most 500 URLs per day.

    If your workloads within your Alibaba Cloud account require a daily bandwidth limit greater than 500 Mbit/s, you can submit a ticket to increase the quota. Alibaba Cloud will review your application and then increase the quota properly.

Content moderation

Alibaba Cloud reviews the content of all accelerated domain names. Domain names that cannot be accelerated by Alibaba Cloud CDN include but are not limited to:

  • Websites whose content is inaccessible or does not provide valid information
  • Servers that host pirated games
  • Websites that provide multiplayer games and card games
  • Websites that provide downloads of pirated software
  • Websites that run peer-to-peer (P2P) lending
  • Lottery websites
  • Websites of unlicensed hospitals and pharmaceuticals
  • Websites that contain pornography, drugs, and gambling content
Note
  • If the preceding content is detected from your accelerated domain name, you must bear the possible risks that may arise. Alibaba Cloud CDN regularly reviews the content of accelerated domain names. If illicit content is detected from a domain name, Alibaba Cloud CDN immediately disables or blocks the domain name. If the violation is severe, Alibaba Cloud CDN may even permanently block all domain names that belong to the Alibaba Cloud account.
  • If you add a wildcard domain name, for example, *.example.com, to Alibaba Cloud CDN and a specific domain name, for example, a.example.com, that matches the wildcard domain name contains illicit content, Alibaba Cloud CDN disables the wildcard domain name (*.example.com).
  • If a domain name fails the review, you can check the reason for rejection on the Domain Names page in the Alibaba Cloud CDN console. Then, you can modify the content based on the rejection details and submit the domain name for review again.
Back-to-origin routing
  • The length of an HTTP request header cannot exceed 300 bytes.
  • Timeout period

    By default, the timeout period for back-to-origin requests that are transmitted over TCP is 10 seconds. The timeout period for back-to-origin requests that are transmitted over HTTP is 30 seconds.

  • Response header

    If an origin server does not respond to Content-Type, Alibaba Cloud CDN automatically adds Content-Type:application/octet-stream.

  • Automatic conversion from HEAD to GET for back-to-origin requests

    By default, HEAD requests are sent to edge nodes before the requests are redirected to origin servers. In this case, HTTP HEAD requests are converted to GET requests. If you want these requests to remain in HEAD, you can navigate to the Custom Request Header tab in the Alibaba Cloud CDN console, and configure custom HTTP headers for back-to-origin requests. The following table describes the parameters of custom HTTP headers. For more information, see Configure an HTTP header for back-to-origin requests.

    Parameter Custom header
    Custom Parameters Ali-Swift-Fwd-Head
    Value on
Bandwidth throttling Based on the Alibaba Cloud International Website Product Terms of Service, if the billing method of your domain name is pay-by-data-transfer or pay-by-bandwidth and the peak bandwidth value within one minute reaches 10 Gbit/s, Alibaba Cloud enables bandwidth throttling for the domain name. Bandwidth throttling protects your domain name from attacks and prevents unexpected high bills. If you want to disable bandwidth throttling, you can contact Alibaba Cloud customer service or submit a ticket.
File
  • File cache
    • If the request to a file that is larger than 100 MB is a cache miss, and the origin server returns a no-cache response header, Alibaba Cloud CDN closes the connection after the amount of data transmitted from the origin server reaches 100 MB.
    • If the origin server returns a response header whose Cache-Control directive allows the response to be cached, edge nodes can cache files that are up to 500 GB in size.
  • File upload

    You can upload files to origin servers through Alibaba Cloud CDN. Each file can be up to 300 MB in size.

EdgeScript By default, you can configure only one script for each domain name. If you want to configure more scripts, submit a ticket.
Stress testing
If you want to run stress tests on a domain name that is accelerated by Alibaba Cloud CDN, you must submit a ticket at least three days in advance. Otherwise, you may experience the following issues:
  • Stress tests on bandwidth may cause bandwidth usage spikes and increase bandwidth costs.
  • Stress tests on the number of queries per second (QPS) may trigger HTTP flood protection rules of Alibaba Cloud CDN and sandbox the domain name.
Length of URLs and request headers
  • HTTP2.0

    In a request, the total length of the URL and request headers cannot exceed 16 KB. Otherwise, an HTTP 414 status code is returned.

  • HTTP1.1

    In a request, the length of the URL cannot exceed 64 KB. Otherwise, an HTTP 414 status code is returned. The total length of the URL and request headers cannot exceed 256 KB. Otherwise, an HTTP 400 status code is returned.

Request method Alibaba Cloud CDN supports the GET, PUT, POST, and HEAD request methods.
Note
  • If you want to support DELETE and PATCH requests, use Dynamic Route for CDN (DCDN) and enable acceleration for dynamic content delivery.
  • Only POST and PUT requests can carry a request body.
  • By default, Alibaba Cloud CDN converts HEAD requests to GET requests before they are redirected to the origin server. If you want to redirect HEAD requests to the origin server, you can add a custom request header on the Custom Request Header tab in the Alibaba Cloud CDN console. The following table describes how to add a custom request header. For more information, see Configure an HTTP header for back-to-origin requests.
Parameter Custom header
Custom Parameters Ali-Swift-Fwd-Head
Value on
Feature configuration You can add at most 50 configuration records, including the following features: Custom Request Header, Custom Response Headers, URI Rewrite, Parameter Rewrite, and Cache Expiration.
Intelligent and Brotli compression Only files that are not smaller than 1 KB are compressed.