> For the complete documentation index, see [llms.txt](https://docs.console.zenlayer.com/api-reference/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.console.zenlayer.com/api-reference/compute/zec/vpc-network/modifysubnetstacktype.md).
# ModifySubnetStackType
## 1. API Description
This API (ModifySubnetStackType) is used to modify the IP stack type of the specified subnet (IPv4, IPv4\_IPv6, or IPv6). When switching to dual-stack or IPv6-only, you must provide the IPv6 type and the corresponding CIDR block configuration.
{% hint style="info" %}
**Note**
* Switching `IPv4` to `IPv4_IPv6` (enabling IPv6): you must specify `ipv6Type` (public `Public` / private `Private`); after the change, an IPv6 address block is assigned to the subnet.
* Switching `IPv4_IPv6` to `IPv4` (disabling IPv6): supported for both public and private IPv6 subnets; before proceeding, all NICs in the subnet must have their IPv6 addresses removed via `UnassignNetworkInterfaceIpv6`.
{% endhint %}
## 2. Input Parameters
The following request parameter list only provides API request parameters.
| Parameter Name | Required | Type | Description |
| --------------- | -------- | ------------------------------------------------------------------------------ | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| subnetId | Yes | String | Subnet ID. |
| stackType | Yes | [SubnetStackType](/api-reference/compute/zec/datastructure.md#subnetstacktype) | IP stack type of the subnet.
IPv4\_IPv6: enable IPv6 — public or private is determined by ipv6Type.
IPv4: disable IPv6 — supported for both public and private IPv6 subnets; before proceeding, all NICs in the subnet must have their IPv6 addresses removed via UnassignNetworkInterfaceIpv6.
|
| ipv6Type | No | [IPv6Type](/api-reference/compute/zec/datastructure.md#ipv6type) | IPv6 type. Required when stackType is IPv4\_IPv6.
Public: public IPv6; Private: private IPv6.
|
| ipv6CidrBlockId | No | String | ID of the public IPv6 CIDR block.
This field can only be specified when ipv6Type is Public.
If not specified, it will be allocated from the system's default IP pool.
|
| ipv6MaskLength | No | Integer | The size of the IPv6 CIDR prefix assigned to the instance.
This parameter must be used together with the ipv6CidrBlockId parameter.
The default value is 96 if not explicitly provided.
The minimum value must be greater than or equal to the prefix of the specified ipv6CidrBlockId, and the maximum value cannot exceed 96.
Value range: \[-, 96]
|
## 3. Output Parameters
| Parameter Name | Type | Description |
| -------------- | ------ | --------------------------------------------------------------------------------------------------------------------- |
| requestId | String | The unique request ID, which is returned for each request.
RequestId is required for locating a problem.
|
| ipv6CidrBlock | String | IPv6 CIDR block of subnet. |
## 4. Code Example
{% tabs %}
{% tab title="Example" %}
**1. Switch the subnet stack type from IPv4 to IPv4\_IPv6 with private IPv6.**
```json
POST /api/v2/zec HTTP/1.1
Host: console.zenlayer.com
Content-Type: application/json
X-ZC-Action: ModifySubnetStackType
Request:
{
"subnetId": "",
"stackType": "IPv4_IPv6",
"ipv6Type": "Private"
}
Response:
{
"requestId": "T05992D0C-7E8B-4047-B0C0-780F2CD549D3",
"response": {
"requestId": "T05992D0C-7E8B-4047-B0C0-780F2CD549D3",
"ipv6CidrBlock": "f0xxxx:xx:xxx::/64"
}
}
```
**2. Disable subnet IPv6: IPv4\_IPv6 → IPv4.**
```json
POST /api/v2/zec HTTP/1.1
Host: console.zenlayer.com
Content-Type: application/json
X-ZC-Action: ModifySubnetStackType
Request:
{
"subnetId": "",
"stackType": "IPv4"
}
Response:
{
"requestId": "T05992D0C-7E8B-4047-B0C0-780F2CD549D3",
"response": {
"requestId": "T05992D0C-7E8B-4047-B0C0-780F2CD549D3"
}
}
```
{% endtab %}
{% endtabs %}
## 5. Developer Resources
Zenlayer Cloud API 2.0 integrates [SDKs](/api-reference/api-introduction/toolkit/api-sdk.md)，to make it easier for you to call APIs. More programming languages will be supported.
## 6. Error Codes
The following only lists the error codes related to the API business logic. For other error codes, see [Common Error Codes](/api-reference/api-introduction/instruction/commonerrorcode.md).
| HTTP Status Code | Error Code | Description |
| ---------------- | -------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------- |
| 400 | INVALID\_CIDR\_BLOCK\_STATUS | The CIDR block state is invalid. |
| 404 | INVALID\_CIDR\_IPV6\_NOT\_FOUND | IPv6 CIDR block does not exist |
| 400 | INVALID\_CIDR\_REGION\_MISMATCH | The subnet region does not match the IPv6 CIDR block region. |
| 400 | INVALID\_MASK\_LENGTH | The IPv6 address mask length must be greater than or equal to the subnet IPv6 prefix length. |
| 400 | INVALID\_SUBNET\_HAS\_IPV6\_ALLOCATED | The subnet still has network interfaces with IPv6 allocated. Please call UnassignNetworkInterfaceIpv6 on all of them first. |
| 404 | INVALID\_SUBNET\_NOT\_FOUND | Subnet does not exist. |
| 404 | INVALID\_VPC\_NOT\_FOUND | The global VPC does not exist. |
| 404 | INVALID\_ZONE\_NOT\_FOUND | Region does not exist. |
| 400 | OPERATION\_DENIED\_NO\_AVAILABLE\_CIDR | No available CIDR block. |
| 400 | OPERATION\_DENIED\_REGION\_NOT\_SUPPORT\_PUB\_IPV6 | Public IPv6 is not supported in the specified region. |
| 400 | OPERATION\_DENIED\_SUBNET\_TYPE\_NOT\_SUPPORT | Operations on subnets with such IP stack type is not supported. |
| 400 | OPERATION\_DENIED\_VPC\_NOT\_SUPPORT\_PRI\_IPV6 | Private IPv6 is not supported for the specified global VPC. |