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Last Updated:Jan 29, 2023

Adds the filtering policies for UDP reflection attacks on an Anti-DDoS Pro or Anti-DDoS Premium instance to filter out the source ports of UDP traffic.

Operation Description

You can call this operation to configure filtering policies to filter out UDP traffic from specific ports. This helps defend against UDP reflection attacks.


You can call this operation up to 10 times per second per account. If the number of the calls per second exceeds the limit, throttling is triggered. As a result, your business may be affected. We recommend that you take note of the limit when you call this operation.

Authorization information

The following table is the authorization information corresponding to the API, which can be found in the RAM permission policy statement.Action Used in the element to grant the RAM user or RAM role permission to call this API. The specific instructions are as follows:

  • Operation: the value that you can use in the Action element to specify the operation on a resource.
  • Access level: the access level of each operation. The levels are read, write, and list.
  • Resource type: the type of the resource on which you can authorize the RAM user or the RAM role to perform the operation. Take note of the following items:
    • The required resource types are displayed in bold characters.
    • If the permissions cannot be granted at the resource level, All resources is used in the Resource type column of the operation.
  • Condition keyword: refers to the condition keyword defined by the cloud product itself.
  • Associated operation: other operations that the RAM user or the RAM role must have permissions to perform to complete the operation. To complete the operation, the RAM user or the RAM role must have the permissions to perform the associated operations.
Operateaccess levelResource typeconditional keywordAssociation operation
  • DdosCoo

Request parameters


The ID of the instance.

NoteYou can call the DescribeInstanceIds operation to query the IDs of all instances.

The configuration of the filtering policy for UDP reflection attacks.

The value is a string that consists of a JSON struct. The JSON struct contains the following fields:

  • UdpSports: the source ports of the UDP traffic that you want to block. This field is required and must be of the ARRAY type. Example: [17,19].

    We recommend that you block the following source ports of UDP traffic:

    • UDP 17: QOTD reflection attacks
    • UDP 19: CharGEN reflection attacks
    • UDP 69: TFTP reflection attacks
    • UDP 111: Portmap reflection attacks
    • UDP 123: NTP reflection attacks
    • UDP 137: NetBIOS reflection attacks
    • UDP 161: SNMPv2 reflection attacks
    • UDP 389: CLDAP reflection attacks
    • UDP 1194: OpenVPN reflection attacks
    • UDP 1900: SSDP reflection attacks
    • UDP 3389: RDP reflection attacks
    • UDP 11211: memcached reflection attacks

The region ID of the instance. Valid values:

  • cn-hangzhou: Chinese mainland, which indicates Anti-DDoS Pro instances. This is the default value.
  • ap-southeast-1: outside the Chinese mainland, which indicates Anti-DDoS Premium instances.

All Alibaba Cloud API operations must include common request parameters. For more information about common request parameters, see Common parameters.

For more information about sample requests, see the "Examples" section of this topic.

Response parameters


The ID of the request.



Normal return example


  "RequestId": "9EC62E89-BD30-4FCD-9CB8-FA53865FF0D7"

Error codes

For a list of error codes, visit the API error center.