Help Center> Virtual Private Cloud> User Guide (Paris Regions) > VPC and Subnet> IPv4 and IPv6 Dual-Stack Network
Updated on 2024-03-05 GMT+08:00
View PDF

IPv4 and IPv6 Dual-Stack Network

What Is an IPv4/IPv6 Dual-Stack Network?

IPv4 and IPv6 dual-stack allows your resources, such as ECSs, to use both IPv4 and IPv6 addresses for private and public network communications. For example, if ECSs use the IPv4/IPv6 dual-stack network:
  • ECSs can communicate with each other using private IPv4 addresses.
  • ECSs can communicate with the Internet after they are bound with EIPs.
  • ECSs can communicate with each other using IPv6 addresses.
  • ECSs can communicate with the Internet after their IPv6 addresses are added to shared bandwidths.

If you select Enable for IPv6 CIDR Block when creating a subnet, an IPv6 CIDR block will be automatically assigned to the subnet.

Basic operations on IPv4 and IPv6 dual-stack networks are the same as those on IPv4 networks, except some parameters. Check the console pages for details.

Notes and Constraints

  • The IPv4/IPv6 dual-stack function is currently free, but will be billed at a later date (price yet to be determined).
  • Only certain ECS specifications support IPv6 networks and can use IPv4/IPv6 dual-stack networks. You need to select such ECSs in supported regions.
    To check which ECSs support IPv6:
    • On the ECS console: Click Create ECS. On the displayed page, view the ECS specifications.

      If there is the IPv6 parameter with the value of Yes, the ECS specifications support IPv6.

IPv6 Application Scenarios

If your ECS supports IPv6, you can use the IPv4/IPv6 dual-stack network. Table 1 shows the example application scenarios.
Table 1 Application scenarios of IPv4/IPv6 dual stack

Application Scenario

Description

Subnet

ECS

Private communication using IPv6 addresses

Your applications deployed on ECSs need to communicate with other systems (such as databases) through private networks using IPv6 addresses.
  • IPv4 CIDR block
  • IPv6 CIDR block
  • Private IPv4 address: used for private communication
  • IPv6 address: used for private communication.

Public communication using IPv6 addresses

Your applications deployed on ECSs need to provide services accessible from the Internet using IPv6 addresses.
  • IPv4 CIDR block
  • IPv6 CIDR block
  • Private IPv4 address + IPv4 EIP: used for public network communication
  • IPv6 address + shared bandwidth: used for public network communication

Your applications deployed on ECSs need to both provide services accessible from the Internet and analyze the access request data using IPv6 addresses.

Basic Operations

Creating an IPv6 Subnet

Create an IPv6 subnet by following the instructions in Creating a Subnet for the VPC. Select Enable for IPv6 CIDR Block. An IPv6 CIDR block will be automatically assigned to the subnet. IPv6 cannot be disabled after the subnet is created.

Figure 1 Creating an IPv6 subnet

Viewing In-Use IPv6 Addresses

In the subnet list, click the subnet name. On the displayed page, view in-use IPv4 and IPv6 addresses on the IP Addresses tab.

Adding a Security Group Rule (IPv6)

Add a security group rule with Type set to IPv6 and Source or Destination set to an IPv6 address or IPv6 CIDR block.

Figure 2 Adding a security group rule (IPv6)

Adding an IPv6 Network ACL Rule

Add a network ACL rule with Type set to IPv6 and Source or Destination set to an IPv6 address or IPv6 CIDR block.

Figure 3 Adding an IPv6 network ACL rule

Adding an IPv6 EIP or Dual-Stack NIC IPv6 Address to a Shared Bandwidth

Add an IPv6 EIP or a dual-stack NIC IPv6 address to a shared bandwidth by following the instructions provided in Adding EIPs to a Shared Bandwidth.

Figure 4 Adding a dual-stack NIC IPv6 address to a shared bandwidth

Adding a Route (IPv6)

Add a route with Destination and Next Hop set to an IPv4 or IPv6 CIDR block. For details about how to add a route, see Adding a Custom Route. If the destination is an IPv6 CIDR block, the next hop can only be an IP address in the same VPC as the IPv6 CIDR block.

If the destination is an IPv6 CIDR block, the next hop type can only be an ECS, extension NIC, or virtual IP address. The next hop must also have IPv6 addresses.

Figure 5 Add Route

Assigning an IPv6 Virtual IP Address

Assign a virtual IPv4 or IPv6 address by referring to Assigning a Virtual IP Address.

Figure 6 Assigning a Virtual IP Address

Each virtual IPv6 address can only be bound to one dual-stack NIC.

Dynamically Assigning IPv6 Addresses

After an ECS is created successfully, you can view the assigned IPv6 address on the ECS details page. You can also log in to the ECS and run the ifconfig command to view the assigned IPv6 address.

If an IPv6 address fails to be automatically assigned or the selected image does not support the function of automatic IPv6 address assignment, manually obtain the IPv6 address by referring to "Dynamically Assigning IPv6 Addresses" in Elastic Cloud Server User Guide.

If an ECS is created from a public image:

Before enabling dynamic IPv6 address assignment for a Linux public image, check whether IPv6 is supported and then check whether dynamic IPv6 address assignment has been enabled. Currently, all Linux public images support IPv6, and dynamic IPv6 address assignment is enabled for Ubuntu 16 by default. You do not need to configure dynamic IPv6 address assignment for the Ubuntu 16 OS. For other Linux public images, you need to enable this function.

Parent topic: VPC and Subnet