Enabling IPv4/IPv6 Dual Stack

Scenarios

IPv4/IPv6 dual stack allows your BMSs to use both IPv4 and IPv6 addresses for private and public network communications. This section describes how to enable IPv4/IPv6 dual stack.

Notes

• Currently, you can only enable IPv6 when creating a BMS, rather than when adding a NIC. After IPv6 is enabled, it cannot be disabled.
• After IPv6 is enabled, IPv6 CIDR blocks will be automatically assigned to subnets. You are not allowed to specify a custom IPv6 CIDR block.
• After IPv4/IPv6 dual stack is enabled, a BMS has an IPv4 and an IPv6 address, and cannot use the IPv6 address alone.

Procedure

1. Enable IPv6 for a VPC subnet.
   1. On the management console, choose Network > Virtual Private Cloud from the service list.

      The VPC console is displayed.

   2. Locate the target VPC and click the number of subnets.

      The Subnets page is displayed.

   3. Locate the target subnet and click Enable IPv6.
   4. In the Enable IPv6 dialog box, click Yes.
      

      IPv6 cannot be disabled.

2. Create a BMS and enable IPv4/IPv6 dual stack.
   • Image

     Select an image that supports IPv6. A public image that supports IPv6 has a tag after the image's OS version. For a private or shared image, you need to find out whether it supports IPv6.

   • VPC

     Select the VPC subnet for which IPv6 has been enabled.

     Figure 1 Network configuration
     
   • NIC

     After you select a subnet with IPv6 enabled, the Self-assigned IPv6 address option will be available when you configure a NIC.

     

     • If you select a private or shared image that does not support IPv6, Self-assigned IPv6 address will not take effect. That is, no IPv6 address can be found in the BMS OS even if Self-assigned IPv6 address is selected. Therefore, you are advised to select a public image that supports IPv6.
     • CentOS 7.3 public images do not support IPv6 address assignment to extension NICs. Therefore, you are advised to use other images.
3. After the BMS is created, log in to BMS and view the IPv6 address assigned to it.

   For example, run the ip addr command on a Linux BMS to query the IPv6 address.

   Figure 2 Example command