IPv4 addresses are widely used in various business scenarios, but the limited nature of IPv4 addresses may complicate business development. IPv6 addresses are more plentiful and compatible with more device types than IPv4 addresses. Elastic Compute Service (ECS) supports both IPv4 and IPv6 addresses.

Comparison between IPv4 and IPv6

Address length32 bits (4 bytes)128 bits (16 bytes)
Number of addresses2^322^128
Address formatxxx.xxx.xxx.xxx

Where xxx is an integral value that can range from 0 to 255. Each x is an integer, and leading zeros can be omitted.



Where each x is a hexadecimal number, and leading zeros can be omitted. You can use a double colon (::) once in an IPv6 address to represent a series of zeros.

Example: CDCD:0000:0000:0000:8475:1111:3900:2020=CDCD::8475:1111:3900:2020

Address Resolution Protocol (ARP)Broadcasts an ARP Request frame to resolve an IP address to a link-layer address.Multicasts a Neighbor Solicitation (NS) message to resolve an IP address to a link layer address.
SecurityImplements a security mechanism based on applications and cannot provide security protection at the IP layer.Supports packet fragmentation to ensure data confidentiality and integrity and provides security protection at the IP layer.
LAN connectionConnects to LANs by using network interfaces.Can work with Ethernet adapters and is supported over virtual Ethernet networks between logical partitions.
Address Type
  • Unicast address
  • Multicast address
  • Broadcast address
  • Unicast address
  • Multicast address
  • Anycast address


  • Only ECS instances of the virtual private cloud (VPC) type support IPv6 addresses.
  • Instance type: For more information about whether an instance supports IPv6, see Overview of instance families.
  • Number of IPv6 addresses: You can configure one or more IPv6 addresses for each ECS instance. The number is determined by the instance type. For more information, see Overview of instance families.
  • IPv6 addresses can be used for communication within a VPC. If you want to allow traffic to or from the IPv6 address over the Internet, you must enable public bandwidth for the IPv6 address. For more information, see Step 3: Enable IPv6 public bandwidth.