IPv6 CIDR Block

Description

When creating a subnet, you can customize IPv4 CIDR blocks but not IPv6 CIDR blocks. If you enable IPv6, the system assigns an IPv6 CIDR block with a 64-bit mask to the subnet, for example, 2407:c080:802:1b32::/64. Once enabled, IPv6 cannot be disabled later.

IPv4/IPv6 dual stack network allows your resources, such as ECSs, to use both IPv4 and IPv6 addresses for private and public network communications. Figure 1 shows an IPv4/IPv6 dual stack network.

Figure 1 The architecture of an IPv4/IPv6 dual-stack network

• ECSs can communicate with each other using private IPv4 addresses through an internal network.
• ECSs can communicate with the Internet after they are bound with EIPs.
• ECSs can communicate with each other using IPv6 addresses through an internal network.
• ECSs can communicate with the Internet after their IPv6 addresses are added to shared bandwidths.

Only ECSs with certain flavors support IPv6 networks. You need to select such ECSs in supported regions. You can view the flavors of ECSs on the ECS console.

On the ECS console, click Buy ECS. On the displayed page, view the ECS flavors. If the value of IPv6 is Yes, the ECSs with this flavor support IPv6.

FAQ