Enable IPv6 communication for an ECS instance - Elastic Compute Service

To use IPv6 for private and public communication in a Virtual Private Cloud (VPC), you must create an ECS instance that has an IPv6 address. The instance must be located in a VPC and vSwitch for which IPv6 is enabled. This topic describes how an ECS instance communicates using an IPv6 address and how to assign and configure an IPv6 address for an ECS instance.

Note

IPv4 has a limited number of network addresses. Network engineers often spend a great deal of time and effort resolving issues such as address conflicts in IPv4 environments. In contrast, IPv6 provides a vast address space. This resolves the address shortage problem and removes barriers for devices that connect to the Internet.

Limits

Regions that support IPv6 Gateway

Note

IPv6 Gateway is a gateway for IPv6 traffic in a VPC. By default, an assigned IPv6 address can be used only for private communication. To enable public communication, you must enable IPv6 Internet bandwidth for the IPv6 address on the IPv6 Gateway. For more information, see IPv6 Gateway.

Area	Regions
Asia Pacific - China	China (Qingdao), China (Beijing), China (Zhangjiakou), China (Hohhot), China (Ulanqab), China (Hangzhou), China (Shanghai), China (Fuzhou - Local Region), China (Shenzhen), China (Heyuan), China (Guangzhou), China (Chengdu), and China (Hong Kong)
Asia Pacific - Others	Philippines (Manila), Singapore, Japan (Tokyo), South Korea (Seoul), Indonesia (Jakarta), Malaysia (Kuala Lumpur), and Thailand (Bangkok)
Europe & Americas	US (Virginia), US (Silicon Valley), Germany (Frankfurt), UK (London), and Mexico
Middle East	SAU (Riyadh - Partner Region) Important

ECS instance families that do not support IPv6

The ic5 intensive-computing instance family
The se1 memory-optimized instance family
The d1 big data instance family
The i2g and i1 local SSD-equipped instance families
The hfc5 (high-frequency compute-optimized) and hfg5 (high-frequency general-purpose) instance families
The ebmg5 (general-purpose) and ebmr5s (memory-optimized network-enhanced) ECS Bare Metal Instance families
The xn4, n4, mn4, and e4 previous-generation shared instance families
The scch5 high-frequency Super Computing Cluster instance family
The gn5 GPU-accelerated computed optimized instance family
The n1, n2, and e3 shared instance families
The sn2 and sn1 general-purpose instance families

Limits on the number of IPv6 addresses that can be assigned to an ECS instance

The number of IPv6 addresses that you can assign to a single ECS instance depends on the number of Elastic Network Interfaces (ENIs) that can be attached to the instance and the number of IPv6 addresses that can be assigned to each ENI:

The number of IPv6 addresses that can be assigned to a single ENI depends on the instance type. For more information, see the Number of IPv6 addresses per ENI column in Instance families.
The number of ENIs that can be attached to a single instance depends on the instance type. For more information, see the Elastic Network Interface column in Instance families.

Procedure

Note

You can use one-click deployment to quickly complete the following operations.

Step 1: Enable IPv6 for a VPC and a vSwitch

First, ensure that IPv6 is enabled for the VPC and vSwitch in which the ECS instance resides. For more information, see Enable IPv6 for a VPC and Enable IPv6 for a vSwitch.

Step 2: Assign an IPv6 address

You can assign an IPv6 address to an ECS instance to allow the instance to communicate with other instances or external networks using IPv6.

Assign an IPv6 address to an existing instance

Go to ECS console - Instances.
In the top navigation bar, select the region and resource group of the resource that you want to manage.
Locate the target ECS instance and click its instance ID to open the instance details page. In the All Actions section, choose Network And Security Group > Manage IPv6 Address.
In the Manage Secondary Private IP Addresses dialog box, click Increase in the IPv6 section.
If you do not need to specify an IPv6 address, you can leave the IPv6 address field empty. The system automatically assigns an address.
Click Confirm.

Assign an IPv6 address when you create an instance

When you create an instance, note the following configurations. For information about other configurations, see Create an instance using the custom launch tab:

Network and Zone: Select a VPC and a vSwitch that have IPv6 enabled.
Instance: Click View more specification parameters, filter for instance types that support IPv6-supported, and then select an instance type.
Network and Security Groups: Click Elastic ENI | IPv6(Optional) and select Assign IPv6 Address Free of Charge.

After the address is assigned, you can view the IP address details in the ECS console. For more information, see IP addresses.

Step 3: Configure the IPv6 address

Configure the IPv6 address on the network interface card (NIC) of the ECS instance so that the operating system can recognize and use the IPv6 address.

Some images support automatic configuration and recognition of IPv6 addresses. Follow these steps to check whether the operating system of your ECS instance has recognized the IPv6 address.
Linux instances
1. Remotely connect to the Linux instance.
  For more information, see Connect to a Linux instance using Workbench.
2. Run the ip -6 addr show or ifconfig command.
  1. If a global unicast address and a link-local address are returned as shown in the following figure, the IPv6 address is recognized. You do not need to configure the IPv6 address. Otherwise, proceed with the configuration steps.
Windows instances
1. Remotely connect to the Windows instance.
  For more information, see Connect to a Windows instance using Workbench.
2. Open the command line interface and run the ipconfig command.
  1. If a global unicast address and a link-local address are returned as shown in the following figure, the IPv6 address is recognized. You do not need to configure the IPv6 address. Otherwise, proceed with the configuration steps.
Configure the IPv6 address.
Important
To automatically configure an IPv6 address, you must install Cloud Assistant. If your instance does not support Cloud Assistant or you do not want to install it, you must manually configure the IPv6 address.
(Recommended) Automatically configure the IPv6 address
Prerequisites
1. The Cloud Assistant Agent is installed on the instance. If it is not installed, see Install the Cloud Assistant Agent.
2. This method applies only to the following operating systems: Alibaba Cloud Linux 2/3, CentOS 6/7/8, Red Hat 6/7, Anolis OS, Fedora, Ubuntu 14/16/18/20, Debian 8/9/10/11, SUSE 11/12/15, OpenSUSE 15/42, and FreeBSD 11.
Important
This configuration process uses Cloud Assistant. The NIC or network service may be automatically restarted, which causes a temporary network interruption. Proceed with caution.
Procedure
1. Remotely connect to the Linux instance.
  For more information, see Connect to a Linux instance using Workbench.
2. Run the following command to configure the IPv6 address.
  Note
  By default, when you run the following command, the system checks whether the ecs-utils-ipv6 plugin is installed and whether the installed version is the latest. If the plugin is not installed or the version is outdated, the system automatically downloads and installs the latest version.
```
sudo acs-plugin-manager --exec --plugin=ecs-utils-ipv6
```
Manual configuration (Linux)
1. Remotely connect to the Linux instance.
  For more information, see Connect to a Linux instance using Workbench.
2. Run the ip addr | grep inet6 or ifconfig | grep inet6 command to check whether the IPv6 service is enabled on the instance.
  1. If no information related to inet6 is returned, the IPv6 service is disabled. You must enable the IPv6 service.
    How do I enable the IPv6 service?
    Alibaba Cloud Linux 2/3
    Run the following command to modify the /etc/sysctl.conf configuration file.
    vi /etc/sysctl.conf
    Press the I key to enter edit mode. Find the following parameters and change their values from 1 to 0.
    net.ipv6.conf.all.disable_ipv6 = 1 net.ipv6.conf.default.disable_ipv6 = 1 net.ipv6.conf.lo.disable_ipv6 = 1
    To enable IPv6 for a specific network interface, modify the related parameter as shown in the following example.
    net.ipv6.conf.eth0.disable_ipv6 = 0
    After you make the changes, press the Esc key to exit edit mode. Then, enter :wq and press the Enter key to save the file and exit.
    Run the following command to check whether the /etc/sysctl.conf configuration information is different from the /etc/sysctl.conf information in initramfs.
    diff -u /etc/sysctl.conf <(lsinitrd -f /etc/sysctl.conf)
    Note
    Alibaba Cloud Linux 2 is configured with the initial RAM file system (initramfs). If the /etc/sysctl.conf file in initramfs is different from the IPv6 configuration file /etc/sysctl.conf, the system may load a conflicting configuration upon restart.
    If the two configuration files are different, run the following command to regenerate initramfs.
    sudo dracut -v -f
    Restart the ECS instance for the configuration to take effect. For more information, see Restart an instance.
    Run the ip addr | grep inet6 or ifconfig | grep inet6 command to verify that IPv6 is enabled.
    If information related to inet6 is returned, the IPv6 service is enabled.
    CentOS 6/7
    To modify the /etc/modprobe.d/disable_ipv6.conf configuration file, run the following command.
    vi /etc/modprobe.d/disable_ipv6.conf
    Press the I key to enter edit mode and change options ipv6 disable=1 to options ipv6 disable=0.
    After you make the changes, press the Esc key to exit edit mode. Then, enter :wq and press the Enter key to save the file and exit.
    Run the following command to modify the /etc/sysconfig/network configuration file.
    vi /etc/sysconfig/network
    Press the I key to enter edit mode and change NETWORKING_IPV6=no to NETWORKING_IPV6=yes.
    After you make the changes, press the Esc key to exit edit mode. Then, enter :wq and press the Enter key to save the file and exit.
    (Optional) Run the following commands in sequence to reload the IPv6 module.
    Note
    If your operating system is CentOS 6, you must perform this step. Otherwise, you can skip this step.
    modprobe ipv6 -r modprobe ipv6 lsmod | grep ipv6
    If the following information is returned, the IPv6 module is loaded.
    ipv6 xxxxx 8
    Note
    The value in the third column of the returned information must not be 0. Otherwise, you must reconfigure the IPv6 service.
    Run the following command to modify the /etc/sysctl.conf configuration file.
    vi /etc/sysctl.conf
    Press the I key to enter edit mode. Find the following parameters and change their values from 1 to 0.
    net.ipv6.conf.all.disable_ipv6 = 1 net.ipv6.conf.default.disable_ipv6 = 1 net.ipv6.conf.lo.disable_ipv6 = 1
    After you make the changes, press the Esc key to exit edit mode. Then, enter :wq and press the Enter key to save the file and exit.
    Run the following command for the configuration to take effect.
    sudo sysctl -p
    Debian 8/9
    Run the following command to modify the /etc/default/grub configuration file.
    vi /etc/default/grub
    Press the I key to enter edit mode and delete ipv6.disable=1.
    After you make the changes, press the Esc key to exit edit mode. Then, enter :wq and press the Enter key to save the file and exit.
    Run the following command to modify the /boot/grub/grub.cfg configuration file.
    vi /boot/grub/grub.cfg
    Press the I key to enter edit mode and delete ipv6.disable=1.
    After you make the changes, press the Esc key to exit edit mode. Then, enter :wq and press the Enter key to save the file and exit.
    Restart the Linux instance. For more information, see Restart an instance.
    Run the following command to modify the /etc/sysctl.conf configuration file.
    vi /etc/sysctl.conf
    Press the I key to enter edit mode. Find the following parameters and change their values from 1 to 0.
    net.ipv6.conf.all.disable_ipv6 = 0 net.ipv6.conf.default.disable_ipv6 = 0 net.ipv6.conf.lo.disable_ipv6 = 0
    After you make the changes, press the Esc key to exit edit mode. Then, enter :wq and press the Enter key to save the file and exit.
    Run the following command for the configuration to take effect.
    sudo sysctl -p
    Ubuntu 14/16 and OpenSUSE 42
    Run the following command to modify the vi /etc/sysctl.conf configuration file.
    vi /etc/sysctl.conf
    Press the I key to enter edit mode. Find the following parameters and change their values from 1 to 0.
    net.ipv6.conf.all.disable_ipv6 = 0 net.ipv6.conf.default.disable_ipv6 = 0 net.ipv6.conf.lo.disable_ipv6 = 0
    After you make the changes, press the Esc key to exit edit mode. Then, enter :wq and press the Enter key to save the file and exit.
    Run the following command for the configuration to take effect.
    sysctl -p
    FreeBSD 11
    Run the following command to modify the /etc/rc.conf configuration file.
    vi /etc/rc.conf
    Press the I key to enter edit mode and add the ipv6_activate_all_interfaces="YES" line.
    After you make the changes, press the Esc key to exit edit mode. Then, enter :wq and press the Enter key to save the file and exit.
    Run the following command to restart the network for the configuration to take effect.
    /etc/netstart restart
    SUSE 11/12
    Run the following command to modify the /etc/modprobe.d/50-ipv6.conf configuration file.
    vi /etc/modprobe.d/50-ipv6.conf
    Press the I key to enter edit mode and delete the install ipv6 /bin/true line.
    After you make the changes, press the Esc key to exit edit mode. Then, enter :wq and press the Enter key to save the file and exit.
    Run the following command to modify the vi /etc/sysctl.conf configuration file.
    vi /etc/sysctl.conf
    Press the I key to enter edit mode. Find the following parameters and change their values from 1 to 0.
    net.ipv6.conf.all.disable_ipv6 = 0 net.ipv6.conf.default.disable_ipv6 = 0 net.ipv6.conf.lo.disable_ipv6 = 0
    After you make the changes, press the Esc key to exit edit mode. Then, enter :wq and press the Enter key to save the file and exit.
    Run the following command for the configuration to take effect.
    sysctl -p
  2. If information related to inet6 is returned, the IPv6 service is enabled. You must configure the IPv6 address.
3. Configure the IPv6 address.
  Alibaba Cloud Linux 2/3, CentOS 6/7, and Red Hat 6/7
  Run the following command to modify the NIC configuration file.
  vi /etc/sysconfig/network-scripts/ifcfg-eth0
  Replace eth0 with the actual NIC name. After you make the changes, save the file and exit.
  Press the I key to enter edit mode and add the following configuration lines to the file.
  DHCPV6C=yes IPV6INIT=yes
  After you make the changes, press the Esc key to exit edit mode. Then, enter :wq and press the Enter key to save the file and exit.
  Restart the ECS instance for the configuration to take effect. For more information, see Restart an instance.
  CentOS 8
  Check whether the NIC configuration file contains the IPV6INIT=yes and DHCPV6C=yes lines. If the file does not contain these lines, you must manually add them before you proceed to the next step.
  vi /etc/sysconfig/network-scripts/ifcfg-eth0
  Replace eth0 with the actual NIC identifier. After you make the changes, save the file and exit.
  Disable the cloud-init feature that modifies the NIC configuration file in the /etc/sysconfig/network-scripts/ directory.
  Note
  An assigned IPv6 address is automatically configured. However, the configuration may be lost after a restart. To prevent this issue, you must disable the cloud-init feature that modifies the NIC configuration file.
  Run vi /etc/cloud/cloud.cfg to open the NIC configuration file.
  vi /etc/cloud/cloud.cfg
  Add the following information before the Example datasource config section:
  network: config: disabled
  After you make the changes, save the file and exit.
  Restart the ECS instance for the configuration to take effect. For more information, see Restart an instance.
  Debian 8/9/10/11 and Ubuntu 16
  Run vi /etc/network/interfaces to open the NIC configuration file and add the following lines to the file:
  iface eth0 inet6 dhcp
  Replace eth0 with the actual NIC name. After you make the changes, save the file and exit.
  Restart the ECS instance for the configuration to take effect. For more information, see Restart an instance.
  Ubuntu 18/20
  Disable the cloud-init feature that modifies the NIC configuration file in the /etc/sysconfig/network-scripts/ directory.
  Note
  An assigned IPv6 address is automatically configured. However, the configuration may be lost after a restart. To prevent this issue, you must disable the cloud-init feature that modifies the NIC configuration file.
  Run vi /etc/cloud/cloud.cfg to open the NIC configuration file.
  vi /etc/cloud/cloud.cfg
  Add the following information before the Example datasource config section:
  network: config: disabled
  After you make the changes, save the file and exit.
  Restart the ECS instance for the configuration to take effect. For more information, see Restart an instance.
  Ubuntu 14
  Run vi /etc/network/interfaces to open the NIC configuration file and add the following lines to the file:
  iface eth0 inet6 dhcp
  Replace eth0 with the actual NIC name. After you make the changes, save the file and exit.
  Restart the ECS instance for the configuration to take effect. For more information, see Restart an instance.
  FreeBSD 11
  Run the vi /etc/rc.conf command to open the NIC configuration file and add the following lines to the file:
  ipv6_enable="YES" ipv6_ifconfig_vtnet0="<IPv6 address> <Subnet prefix length>"
  Replace vtnet0 with the actual NIC name. After you make the changes, save the file and exit.
  Add the following lines to the file. After you make the changes, save the file and exit.
  ip6addrctl_enable="YES" ipv6_activate_all_interfaces="YES" ipv6_network_interfaces="auto"
  After the modification, the configuration file is similar to the following example:
  hostname="Aliyun" sshd_enable="YES" dumpdev="NO" ipv6_enable="YES" ip6addrctl_enable="YES" ip6addrctl_policy="ipv4_prefer" ipv6_activate_all_interfaces="YES" ipv6_network_interfaces="auto" ifconfig_lo0="inet 127.0.0.1 netmask 255.0.0.0" ifconfig_vtnet0="inet 192.168.XX.XX netmask 255.255.255.0" ipv6_ifconfig_vtnet0="2001:XXXX:4:4:4:4:4:4 prefixlen 64" defaultrouter="192.168.XX.XX" hostname="freebsd"
  Restart the ECS instance for the configuration to take effect. For more information, see Restart an instance.
  Anolis OS 7.9/8.4, CentOS Stream, and Fedora
  Check whether the NIC configuration file contains the IPV6INIT=yes and DHCPV6C=yes lines. If the file does not contain these lines, you must manually add them.
  vi /etc/sysconfig/network-scripts/ifcfg-eth0
  Replace eth0 with the actual NIC name. After you make the changes, save the file and exit.
  Restart the ECS instance for the configuration to take effect. For more information, see Restart an instance.
Manual configuration (Windows)
1. Remotely connect to the Windows instance.
  For more information, see Connect to a Windows instance using Workbench.
2. Open the command line interface and run the ipconfig command to check whether the IPv6 service is enabled on the instance.
  1. If no information related to inet6 is returned, the IPv6 service is disabled. You must enable the IPv6 service.
    How do I enable the IPv6 service?
    Choose Control Panel > Network and Sharing Center > Network Connections.
    Click the current network connection name to open the status dialog box. Then, click Properties.
    Select Internet Protocol Version 6 (TCP/IPv6).
    For Windows Server 2008/2012/2016/2019/2022, perform the following steps:
    If the IPv6 protocol checkbox is not selected, select it and click OK.
    For Windows Server 2003, perform the following steps:
    The steps vary based on whether the IPv6 protocol exists.
    If the IPv6 protocol exists:
    Select Internet Protocol Version 6 (TCP/IPv6) and click OK.
    If the IPv6 protocol does not exist:
    On the Local Area Connection Properties page, click Install. On the Network Component Type page, select Protocol > Add.
    On the Select Network Protocol page, select Microsoft TCP/IP Version 6 > OK to complete the installation.
    Select Internet Protocol Version 6 (TCP/IPv6) and click OK.
  2. If information related to inet6 is returned, the IPv6 service is enabled. You must configure the IPv6 address.
3. Configure the IPv6 address.
  1. On the instance details page, retrieve the generated IPv6 address.
  2. Configure the IPv6 address.
    For Windows Server 2008/2012/2016, perform the following steps:
    Go to Control Panel > Network.
    Click the current network connection. In the status dialog box, click Properties.
    Select IPv6 Protocol > Properties.
    Select Use the Following IPv6 Address, enter the IPv6 address, subnet prefix length, and IPv6 gateway, and then click OK.
    (Optional) To attach multiple IPv6 addresses, on the Internet Protocol Version 6 (TCP/IP) Properties page, click Advanced and then click Add to perform a batch operation. When you are finished, click OK.
    For Windows Server 2003, perform the following steps:
    Go to Control Panel > Network Connections to find the current network connection name. For example, the name may be Local Area Connection 2.
    On the Windows desktop, press the Win+R key combination to open the Run dialog box. Enter cmd and click OK to open the command line interface.
    Add the IPv6 address.
    To add a single IPv6 address, run the following command:
    netsh interface ipv6 add address "Local Area Connection 2" <IPv6 address>
    To add multiple IPv6 addresses, run the following commands:
    netsh interface ipv6 add address "Local Area Connection 2" <IPv6 address 1> netsh interface ipv6 add address "Local Area Connection 2" <IPv6 address 2>
    Run the following command to add a default route.
    netsh interface ipv6 add route ::/0 "Local Area Connection 2" <IPv6 gateway>
(Conditional) If your ECS instance runs a Linux operating system, perform this step. Otherwise, you can skip this step.
Run the following command to check whether the multi-NIC configuration tool is installed on the instance.
```
ls /sbin/eni-ifscan
```
If the information shown in the following figure is returned, it indicates that the multi-NIC configuration tool is pre-installed on the instance. You must modify the eni-function file of the tool.
Note
If a Linux instance has the multi-NIC configuration tool pre-installed, the IPv6 NIC cannot be automatically recognized because the tool does not support IPv6 by default. Therefore, the instance cannot obtain an IPv6 address after a restart.
How to modify the eni-function file
1. Run the following command to modify the eni-function file.
  vim /etc/eni_utils/eni-function
2. Press the I key to enter edit mode. Change IPV6INIT=no to IPV6INIT=yes, and add the DHCPV6C=yes line. Then, save the file and exit.
Verification: If the command output of ifconfig or ipconfig is the same as the result in Step 1, the configuration is successful.

At this point, the ECS instance can communicate over the private IPv6 network. You can test the private network connectivity as described in the following section.

Test private network connectivity

Note

To test IPv6 network connectivity, ensure that both the server and the client support and are configured with IPv6. For example, for two ECS instances to access each other, both ECS01 and ECS02 must be configured with IPv6.

On instance ECS01, run the ping6 <ECS02 private IPv6 address> command to ping the IPv6 address of instance ECS02 and test the private network connectivity.

If you receive reply messages, the connection is established. The test shows that private IPv6 communication from instance ECS01 to instance ECS02 is working as expected.

On instance ECS02, run the ping6 command to ping the IPv6 address of instance ECS01 and test the private network connectivity.

If you receive reply messages, the connection is established. The test shows that private IPv6 communication from instance ECS02 to instance ECS01 is working as expected.

Step 4: Enable IPv6 Internet bandwidth

By default, the IPv6 address of an ECS instance can be used only for private communication. If you want to use the IPv6 address to access the Internet or be accessed from the Internet, you must enable IPv6 Internet bandwidth by following these steps.

Log on to the VPC console.
In the navigation pane, choose Access to Internet > IPv6 Gateway.
In the top navigation bar, select the region where the IPv6 gateway is deployed.
On the IPv6 Gateway page, find the IPv6 gateway for the instance's VPC, and then click the IPv6 gateway ID.
On the details page of the IPv6 gateway, click the IPv6 Internet Bandwidth tab, find the IPv6 address for which you want to enable Internet bandwidth, and then click Activate Internet Bandwidth in the Actions column.

On the IPv6 Internet Bandwidth (PostPay) page, specify the parameters described in the following table, click Buy Now, and then complete the payment.

Parameter	Description
Traffic	Select a metering method for the Internet bandwidth. Valid values: Pay-By-Bandwidth and Pay-By-Data-Transfer. For more information, see Billing.
Bandwidth	Specify a maximum value for the Internet bandwidth.
Billing cycle	Select a billing cycle for the Internet bandwidth. Valid values: By Day and By Hour. If you set Traffic to Pay-By-Bandwidth, you can select only By Day. If you set Traffic to Pay-By-Data-Transfer, you can select only By Hour.

After you enable IPv6 Internet bandwidth, you can test the public network connectivity of the IPv6 address.

Note

To test IPv6 network connectivity, ensure that both the server and the client support and are configured with IPv6.

ping -6 aliyun.com

If the information shown in the following figure is returned, the network connection is normal. ping -6

Note

In this example, the aliyun.com website supports IPv6. After your ECS instance is configured, you can access aliyun.com using IPv6.

Other operations

Add IPv6 security group rules

IPv4 and IPv6 traffic are independent. If the current security group rules do not meet your business needs, you can configure separate IPv6 security group rules for your ECS instance to enhance network security.

How to add IPv6 security group rules

Go to ECS console - Security Groups.
In the top navigation bar, select the region and resource group of the resource that you want to manage.
Find the target security group and click Manage Rules in the Operation column.
On the security group details page, in the Rules section, select Inbound or Outbound.
Add a security group rule. For more information, see Add a security group rule.
Note
You can set Source to an IPv6 address range, such as 2001:db8:1234:1a00::***. For more information, see Security group rules.

Delete an assigned IPv6 address

If your ECS instance no longer requires an IPv6 address, you can delete it. After the IPv6 address is deleted, you can still use the IPv4 address. This topic describes how to delete an IPv6 address in the ECS console.

Important

Make sure that the instance is in the Running or Stopped state.

Procedure

Go to ECS console - Elastic Network Interfaces.
In the top navigation bar, select the region and resource group of the resource that you want to manage.
On the ENIs page, find the ENI that is attached to the target instance and has an assigned IPv6 address. In the Operation column, click Manage ENI IP Addresses.
In the Manage ENI IP Addresses dialog box, click the icon to the right of the target IPv6 address.
Click Confirm.

References

If an IPv6 address does not require Internet access, you can delete its IPv6 Internet bandwidth. For more information, see Delete IPv6 Internet bandwidth.
You can manage IPv6 traffic in a Virtual Private Cloud (VPC) by adding and managing IPv6 routes in the route table. For more information, see Create and manage IPv6 routes.

Elastic Compute Service:Enable IPv6 communication for an ECS instance

Limits

Regions that support IPv6 Gateway

ECS instance families that do not support IPv6

Limits on the number of IPv6 addresses that can be assigned to an ECS instance

Procedure

Step 1: Enable IPv6 for a VPC and a vSwitch

Step 2: Assign an IPv6 address

Assign an IPv6 address to an existing instance

Assign an IPv6 address when you create an instance

Step 3: Configure the IPv6 address

Linux instances

Windows instances

(Recommended) Automatically configure the IPv6 address

Prerequisites

Procedure

Manual configuration (Linux)

Alibaba Cloud Linux 2/3

CentOS 6/7

Debian 8/9

Ubuntu 14/16 and OpenSUSE 42

FreeBSD 11

SUSE 11/12

Alibaba Cloud Linux 2/3, CentOS 6/7, and Red Hat 6/7

CentOS 8

Debian 8/9/10/11 and Ubuntu 16

Ubuntu 18/20

Ubuntu 14

FreeBSD 11

Anolis OS 7.9/8.4, CentOS Stream, and Fedora

Manual configuration (Windows)

Step 4: Enable IPv6 Internet bandwidth

Other operations

Add IPv6 security group rules

Delete an assigned IPv6 address

Procedure

References