:Configure rate limiting

Enable rate limiting

1. Log on to the Alibaba Cloud CDN console.

2. In the left-side navigation pane, click Domain Names.

3. On the Domain Names page, find the domain name that you want to manage and click Manage in the Actions column.

4. In the left-side navigation pane of the domain name, click Security Settings.

5. Click the Rate Limiting tab.

6. Turn on Rate Limiting.

7. In the Rate Limiting dialog box, turn on Parameter Check and configure the Limiting Mode parameter.

   

   Parameter	Description
   Parameter Check	After you enable parameter check, URIs that include all parameters are matched with rate limiting rules. This feature checks only URIs. Match criteria that are configured in custom rate limiting rules do not apply to this feature. Note Parameter Check takes effect only when you set the Limiting Mode parameter to Custom.
   Limiting Mode	You can select one of the following modes: Normal The default rate limiting mode. If network traffic in your website is within the expected range, select this mode to prevent false positives. Emergency If your website responds slowly and exceptions are detected in network traffic, CPU utilization, memory usage, or other performance metrics, select this mode. Custom If you want to create custom rate limiting rules based on your business requirements, select this mode. This mode detects requests that are frequently sent from IP addresses and mitigates HTTP flood attacks on POPs. For more information about how to create custom rate limiting rules, see Add a custom rate limiting rule.

8. Click OK.

Add a custom rate limiting rule

1. Click Add Rule on the right side of Custom Rules.

2. Follow the on-screen instructions to add a custom rate limiting rule. The following table describes the parameters.

   

   Parameter	Description
   Rule Name	The name must be 4 to 30 characters in length and can contain letters and digits. The names of rules that are configured for the same domain name must be unique.
   URI	The URI that you want to protect. Example: /register. If the URI contains parameters, for example, /user?action=login, you must enable the parameter check feature.
   Matching Mode	Rate limiting rules apply match rules in the following order: exact match, prefix match, and fuzzy match. You can adjust the priorities of the match rules in a rate limiting rule. Match rules are listed and executed based on their priorities. Exact Match In this mode, requests are counted only if the request URIs exactly match the specified URI. Prefix Match In this mode, requests are counted only if the request URIs start with the specified URI. For example, if the specified URI is set to /register, requests that start with /register.html are counted. Fuzzy Match In this mode, requests are counted only if the request URIs match the specified regular expression. You can use periods (.) and asterisks (*) as wildcard characters. A period (.) specifies that the rate limiting rule compares each individual character. An asterisk (*) specifies that the rate limiting rule considers the request a match if any character matches the specified regular expression.
   Monitored Object	Valid values: Source IP Header Domain URL Parameter
   Interval	The period of time during which requests are counted. This parameter takes effect only if you specify a monitored object. Valid values: 10 to 600. Unit: seconds.
   Match Criteria	Click Add Criteria and configure the Type, Parameter, Logical Operator, and Value parameters. Note The number of requests that match the specified criteria on each POP is counted. Triggering the rate limiting rule may take a long period of time. You can send more requests to the POPs to trigger the rule.
   Action	The action that you want to perform after a request matches the specified rule. You can select Block or Bot Detection. Block If this action is triggered, the HTTP 403 status code is returned to the request. Bot Detection If this action is triggered, the HTTP 200 status code is returned to the request and the request is redirected for verification. The request can access the requested resources only if it passes the verification. For example, if an IP address initiates more than five requests within 20 seconds, bot detection is triggered. All requests from the IP address within the following 10 minutes are verified. Requests from this IP address can access resources only if the requests pass human-machine identification.
   TTL	The period of time during which IP addresses remain blocked. The period of time must be at least 60 seconds.

3. Click OK.

Examples

Related API operations

DescribeDomainCcActivityLog: queries the log entries of rate limiting.