At long last Amazon have announced native IPv6 support for EC2 instances in Amazon VPCs. This is great news for those whose IPv6 deployments have been held back by the lack of native IPv6 support in EC2.
The IPv6 service was first released in a limited deployment in the US East (Ohio) Region back in December 2016. It is now available in all regions.
In Amazon VPCs, public IPv6 address bocks are assigned to VPCs in /56 blocks. You can allocated space out of an assigned /56 block to subnets and instances.
Instances are dual stack, that is they can use both native IPv4 and native IPv6. An instance can use IPv6 addresses to communicate with other instances as well as the wider internet.
In contrast with Microsoft Azure, Amazon is not using IPv6 network address translation (NAT). Azure uses a form of Network Prefix Translation (NPTv6) on their load balancers to map between internal and external IPv6 addresses. Azure is also limited in how IPv6 addresses can be used. You cannot assigned IPv6 addresses to existing VMs, whereas in Amazon EC2 you can assign IPv6 addresses to existing instances. In addition, in Azure, you cannot use IPv6 to communicate between VMs. In EC2 you can.
This is an important move forward in the deployment of IPv6. It is to be expected that the few suppliers who continue to provide a legacy-IPv6 only service will move to deploying IPv6 in the near future.