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.
Note
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¶
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.
Application Scenario | Description | Requirement | IPv4 or IPv6 Subnet | ECS |
|---|---|---|---|---|
Private IPv4 communication | Your applications on ECSs need to communicate with other systems (such as databases) through private networks using IPv4 addresses. |
| IPv4 CIDR Block | Private IPv4 address: used for private IPv4 communication. |
Public IPv4 communication | Your applications on ECSs need to communicate with other systems (such as databases) through public IPv4 addresses. |
| IPv4 CIDR Block |
|
Private IPv6 communication | Your applications on ECSs need to communicate with other systems (such as databases) through private IPv6 addresses. |
|
|
|
Public IPv6 communication | An IPv6 network is required for the ECS to access the IPv6 service on the Internet. |
|
|
|
Application Scenario | Description | Subnet | ECS |
|---|---|---|---|
Public communication using IPv6 addresses | Your applications deployed on ECSs need to provide services accessible from the Internet using IPv6 addresses. | IPv4 CIDR block |
|
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.
To disable this function, call the API by referring to Updating Subnet Information.
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.
Adding an IPv6 Firewall Rule
Add a firewall rule with Type set to IPv6 and Source or Destination set to an IPv6 address or IPv6 CIDR block.
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.
Note
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.
Assigning an IPv6 Virtual IP Address
Assign a virtual IPv4 or IPv6 address by referring to Assigning a Virtual IP Address.
Note
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.
Note
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.