Help Center/ Virtual Private Cloud/ API Reference/ VPC APIs (V3)/ VPC/ Adding a Secondary CIDR Block to a VPC

Updated on 2025-10-30 GMT+08:00

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Adding a Secondary CIDR Block to a VPC

Function

The IPv4 CIDR block you specify when you create a VPC is the primary one. The primary CIDR block cannot be changed after the VPC is created. If IP addresses in the primary CIDR block are insufficient, you can call this API to add a secondary CIDR block to a VPC.

Calling Method

For details, see Calling APIs.

URI

PUT /v3/{project_id}/vpc/vpcs/{vpc_id}/add-extend-cidr

**Table 1** Path Parameters
Parameter	Mandatory	Type	Description
project_id	Yes	String	Definition: ID of the project that a VPC belongs to. For details about how to obtain a project ID, see Obtaining a Project ID. Range: None
vpc_id	Yes	String	Definition: VPC ID, which uniquely identifies the VPC. Range: None

Request Parameters

**Table 2** Request body parameters
Parameter	Mandatory	Type	Description
dry_run	No	Boolean	Definition: Whether to only send the check request. Constraints: None Range: true: Only the check request will be sent and no secondary CIDR block will not be added. Check items include mandatory parameters, request format, and constraints. If the check fails, an error will be returned. If the check succeeds, response code 202 will be returned. false: A request will be sent and a secondary CIDR block will be added. Default Value: false
vpc	Yes	AddExtendCidrOption object	Definition: Request body for adding a secondary CIDR block. Constraints: None Range: None Default Value: None

**Table 3** AddExtendCidrOption
Parameter	Mandatory	Type	Description
extend_cidrs	Yes	Array of strings	Definition: Secondary CIDR blocks of a VPC. Constraints: Only IPv4 CIDR blocks are supported. Range: The following CIDR blocks are not supported: 10.0.0.0/8: The IP address range is 10.0.0.0-10.255.255.255. 172.16.0.0/12: The IP address range is 172.16.0.0-172.31.255.255. 192.168.0.0/16: The IP address range is 192.168.0.0-192.168.255.255. 172.31.0.0/16: The IP address range is 172.31.0.0-172.31.255.255. 100.64.0.0/10: The IP address range is 100.64.0.0-100.127.255.255. 214.0.0.0/7: The IP address range is 214.0.0.0-215.255.255.255. 198.18.0.0/15: The IP address range is 198.18.0.0-198.19.255.255. 169.254.0.0/16: The IP address range is 169.254.0.0-169.254.255.255. 0.0.0.0/8: The IP address range is 0.0.0.0-0.255.255.255. 127.0.0.0/8: The IP address range is 127.0.0.0-127.255.255.255. 240.0.0.0/4: The IP address range is 240.0.0.0-255.255.255.255. Default Value: None

Response Parameters

Status code: 200

**Table 4** Response body parameters
Parameter	Type	Description
request_id	String	Definition: Request ID. Range: None
vpc	Vpc object	Definition: Response body for adding a secondary CIDR block. Range: None

**Table 5** Vpc
Parameter	Type	Description
id	String	Definition: VPC ID. After a VPC is created, a VPC ID is generated, which uniquely identifies the VPC. Range: The value is in UUID format with hyphens (-).
name	String	Definition: VPC name. Range: The value can contain 0 to 64 characters. It can include letters, digits, underscores (_), hyphens (-), and periods (.).
description	String	Definition: Description of a VPC. Range: The value can contain no more than 255 characters and cannot contain angle brackets (< or >).
cidr	String	Definition: Available subnets in a VPC. Range: 10.0.0.0/8–24: The IP address ranges from 10.0.0.0 to 10.255.255.255, and the netmask ranges from 8 to 24. 172.16.0.0/12–24: The IP address ranges from 172.16.0.0 to 172.31.255.255, and the netmask ranges from 12 to 24. 192.168.0.0/16–24: The IP address ranges from 192.168.0.0 to 192.168.255.255, and the netmask ranges from 16 to 24. If cidr is not specified, the default value is "".
extend_cidrs	Array of strings	Definition: Secondary CIDR blocks of a VPC. Range: The following CIDR blocks are not supported: 10.0.0.0/8: The IP address range is 10.0.0.0-10.255.255.255. 172.16.0.0/12: The IP address range is 172.16.0.0-172.31.255.255. 192.168.0.0/16: The IP address range is 192.168.0.0-192.168.255.255. 172.31.0.0/16: The IP address range is 172.31.0.0-172.31.255.255. 100.64.0.0/10: The IP address range is 100.64.0.0-100.127.255.255. 214.0.0.0/7: The IP address range is 214.0.0.0-215.255.255.255. 198.18.0.0/15: The IP address range is 198.18.0.0-198.19.255.255. 169.254.0.0/16: The IP address range is 169.254.0.0-169.254.255.255. 0.0.0.0/8: The IP address range is 0.0.0.0-0.255.255.255. 127.0.0.0/8: The IP address range is 127.0.0.0-127.255.255.255. 240.0.0.0/4: The IP address range is 240.0.0.0-255.255.255.255.
status	String	Definition: VPC status. Range: PENDING: The VPC is being created. ACTIVE: The VPC is created.
project_id	String	Definition: ID of the project that a VPC belongs to. Range: None
enterprise_project_id	String	Definition: ID of the enterprise project that a VPC belongs to. Range: The value is 0 or a string that contains a maximum of 36 characters in UUID format with hyphens (-). 0 indicates the default enterprise project.
created_at	String	Definition: Time when a VPC was created. Range: UTC time in the format of yyyy-MM-ddTHH:mm:ssZ
updated_at	String	Definition: Time when a VPC was updated. Range: UTC time in the format of yyyy-MM-ddTHH:mm:ssZ
cloud_resources	Array of CloudResource objects	Definition: Type and number of resources associated with a VPC. For example, subnets and route tables. Range: None
tags	Array of ResponseTag objects	Definition: Tags of a VPC, including tag keys and tag values, which can be used to classify and identify resources. For details, see the tag objects. Range: None

**Table 6** CloudResource
Parameter	Type	Description
resource_type	String	Definition: Resource type. Range: None
resource_count	Integer	Definition: Number of resources. Range: None

**Table 7** ResponseTag
Parameter	Type	Description
key	String	Definition: Tag key. Range: A tag key can contain a maximum of 128 Unicode characters and cannot be left blank. Each tag key of a resource must be unique. The value can contain: Letters Digits Special characters: underscores (_), periods (.), colons (:), plus signs (+), hyphens (-), and equal signs (=) Chinese characters
value	String	Definition: Tag value. Range: Each value can contain a maximum of 255 Unicode characters and can be left blank. The value can contain: Letters Digits Special characters: underscores (_), periods (.), colons (:), plus signs (+), hyphens (-), and equal signs (=) Chinese characters

Status code: 202

**Table 8** Response body parameters
Parameter	Type	Description
request_id	String	Definition: Request ID. Range: None
error_msg	String	Definition: Error message. Range: None
error_code	String	Definition: Error code. Range: None

Example Requests

Add the secondary CIDR block 23.8.0.0/16 to the VPC whose ID is 0552091e-b83a-49dd-88a7-4a5c86fd9ec3.

PUT https://{Endpoint}/v3/{project_id}/vpc/vpcs/0552091e-b83a-49dd-88a7-4a5c86fd9ec3/add-extend-cidr

{
  "vpc" : {
    "extend_cidrs" : [ "23.8.0.0/16" ]
  }
}

Example Responses

Status code: 200

Normal response to the PUT operation. For more status codes, see Status Code.

{
  "request_id" : "84eb4f775d66dd916db121768ec55626",
  "vpc" : {
    "id" : "0552091e-b83a-49dd-88a7-4a5c86fd9ec3",
    "name" : "vpc1",
    "description" : "test1",
    "cidr" : "192.168.0.0/16",
    "extend_cidrs" : [ "23.8.0.0/16" ],
    "enterprise_project_id" : "0",
    "tags" : [ {
      "key" : "key",
      "value" : "value"
    } ],
    "cloud_resources" : [ {
      "resource_type" : "routetable",
      "resource_count" : 1
    } ],
    "status" : "ACTIVE",
    "project_id" : "060576782980d5762f9ec014dd2f1148",
    "created_at" : "2018-03-23T09:26:08",
    "updated_at" : "2018-08-24T08:49:53"
  }
}

Status code: 202

Normal response to the specified preflight request of API V3. For more status codes, see Status Code.

{
  "error_msg" : "Request validation has been passed with dry run...",
  "error_code" : "SYS.0202",
  "request_id" : "cfd81aea3f59eac7128dba4b36d516c8"
}

Status Codes

Status Code	Description
200	Normal response to the PUT operation. For more status codes, see Status Code.
202	Normal response to the specified preflight request of API V3. For more status codes, see Status Code.