Anti-DDoS:Anti-DDoS Lab

How it works

When a client requests a page, Anti-DDoS Proxy checks whether the page contains resource types covered by the active caching rule. If it does, the page is cached in the protection clusters. Subsequent requests for the same page are served directly from the cache, without reaching the origin server.

Cache freshness vs. cache retention

These two behaviors are independent and easy to confuse:

• Cache freshness (Cache Expires In): How long a cached resource is considered valid before Anti-DDoS Proxy checks the origin again. Configurable per custom rule: 1 hour, 1 day, 10 days, or 30 days.

• Cache retention (inactivity eviction): How long a resource stays in cache on a single host. A resource is evicted after 5 minutes of inactivity, regardless of the Cache Expires In setting. If a client requests the resource after eviction, Anti-DDoS Proxy fetches it from the origin server again.

X-Cache response header

Anti-DDoS Proxy uses the X-Cache HTTP header to indicate cache status:

Prerequisites

Before you begin, ensure that you have:

• A website added to an Anti-DDoS Proxy instance that uses the Enhanced function plan. See Add one or more websites

Enable static page caching

1. Log on to the Anti-DDoS Proxy console.

2. In the top navigation bar, select the region of your instance:

   • Chinese Mainland — for Anti-DDoS Proxy (Chinese Mainland) instances

   • Outside Chinese Mainland — for Anti-DDoS Proxy (Outside Chinese Mainland) instances

3. In the left-side navigation pane, choose Anti-DDoS Lab > Website Acceleration.

4. Select the domain name you want to manage.

5. In the Static Page Caching section, turn on Status, then set the Mode parameter. After you enable a mode, the caching policy applies to all URIs in the domain. To cache only a specific URI, set Mode to No Caching and create a custom caching rule for that URI.

   Important

   Static page caching can only be enabled for domain names associated with an Anti-DDoS Proxy instance that uses the Enhanced function plan.

   Mode	What gets cached
   Standard	Pages that contain static resources (CSS, JavaScript, or TXT files)
   Enhanced	All requested pages
   No Caching	Nothing — use this when you want custom rules to control caching for specific URIs

Create a custom caching rule

Custom caching rules let you apply a specific caching mode and expiry to a single URI path. A custom rule takes priority over the domain-level caching mode and is subject to a limit of five rules.

1. In the Static Page Caching section, click Settings.

2. On the page that appears, click Create Rule in the upper-right corner.

3. In the Create Rule dialog box, configure the following parameters, then click OK.

   Parameter	Description
   Rule name	A name for the rule. Use letters, digits, and underscores only. Maximum length: 128 characters.
   URI	The URI path to cache. Wildcards and request parameters are not supported. For example, /a/ matches all pages under <domain>/a/.
   Mode	The caching behavior for the matched URI: Standard Mode (cache pages with static resources), Strong Mode (cache all pages), or No Caching (bypass cache).
   Cache Expires In	How long cached resources are considered fresh. Default: Use Origin Configurations (honors the origin server's cache headers). Other options: 1Hours, 1Days, 10Days, 30Days. Resources are still evicted after 5 minutes of inactivity, regardless of this setting.

After the rule is created, it appears in the rule list. Use the Edit and Delete actions to manage the rule.

Refresh the cache

To force Anti-DDoS Proxy to fetch a fresh copy from the origin, click Refresh Cache in the rule list.

Use this after updating origin content when you want the cache to reflect the change immediately, without waiting for the resource to expire or be evicted.

Limitations